Knorr-bremse Kb4ta User manual

KB4TA and KB4TA D

24 Volt Multi-channel Trailer ABS

Automatic anti-lock conguration to 2S/2M and 4S/2M

Several diagnostic options available

Retrotable to existing trailers

KB4TA

With integrated anti-compounding

Product Manual

System and Installation

Instructions for KB4TA

and KB4TA D

Y026787 (EN - Rev. 006)

September 2016

Y026787: 006: EN: Released: Fri Nov 11 11:18:50 CET 2016:

Revision Details

Rev. 000 July 2016 New document.

Rev. 001 September 2016 Changes made to suit the Brazilian market.

Y026787: 006: EN: Released: Fri Nov 11 11:18:50 CET 2016:

Knorr-Bremse Group

Doc. No. Y250903 (EN - Rev. 000)

July 2016

Knorr-Bremse Systeme für Nutzfahrzeuge GmbH .Moosacher Straße 80 .80809 Munich .Germany .Tel:+49 89 3547-0 .Fax: +49 89 3547-2767 .www.knorr-bremse.com .www.knorr-bremseCVS.com

Commercial Vehicle Systems

Introduction and Disclaimer

Introduction

This Product Manual is designed to provide an overview of the functions and features of the KB4TA and KB4TA D

brake systems available from Knorr-Bremse. It is made up of individual documents, each covering a major module

or feature of the system. These documents carry two forms of reference number:

• A Document Number, Y******

• A Product Data Number, PD-***-***.

References within a document to other documents does not necessarily imply that those other documents are

contained in this manual but generally they can be found on our website as described below.

Whilst every effort has been made to ensure the accuracy of the data in this manual, we reserve the right to amend

or change this information without notice. The latest versions of individual documents and this manual can be found

on our website: www.Knorr-BremseCVS.com in the Documentation Download section by entering either of the two

forms of reference number in the search ﬁeld. The documents can be downloaded free of charge.

Should you ﬁnd any errors or omissions or have any comments regarding manual layout, please send the details to

your local Knorr-Bremse representative.

The information contained in this manual is intended for the exclusive use of trained persons within the commercial

vehicle industry, and must not be passed on to any third party.

The information is subject to alteration without notice and therefore may not be the latest release. Please check our

website www.knorr-bremseCVS.com for the latest update or contact your local Knorr-Bremse representative.

The information does not purport to be all-inclusive and no responsibility is assumed as a result of its use. We cannot

accept any liability nor offer any guarantee regarding data accuracy, completeness or timeliness. The information

does not represent any guarantee or ensured characteristics of the Products or Systems described.

No liability can be accepted based on the information, its use, recommendations or advice provided. In no event may

we be held liable for any damage or loss except in the case of wilful intent or gross negligence on our part, or if any

mandatory legal provisions apply.

Note: If service work is carried out on a vehicle based on information taken from this document, it is the responsibility

of the workshop to ensure the vehicle is fully tested and in full functional order before the vehicle is returned into

service. Knorr-Bremse accepts no liability for problems caused as a result of appropriate tests not being carried

out.

This disclaimer is an English translation of a German text, which should be referred to for all legal purposes.

Any legal disputes arising from the use of this information shall be subject to German law.

Disclaimer

Y026787: 006: EN: Released: Fri Nov 11 11:18:50 CET 2016:

Knorr-Bremse Group

Knorr-Bremse Systeme für Nutzfahrzeuge GmbH .Moosacher Straße 80 .80809 Munich .Germany .Tel:+49 89 3547-0 .Fax: +49 89 3547-2767 .www.knorr-bremse.com .www.knorr-bremseCVS.com

Doc. No. Y250903 (EN - Rev. 000)

July 2016

Glossary of Abbreviations

ABS Anti-lock Braking System

AUXIO Auxiliary Input/Output

CAN Controller Area Network

ECE Economic Commission for Europe (United

Nations)

ECU Electronic Control Unit

EU European Union (formerly EEC -European

Economic Community)

GND Ground

IAM Independent Aftermarket

IGN Ignition (vehicle power supply)

ISS Integrated Speed Switch

MV Modulator Valve

OE Original Equipment

OEM Original Equipment Manufacturer

RtR Reset-to-Ride Height

TT CAN Tractor Trailer CAN (ISO11992 24 v)

USB Universal Serial Bus

WSS Wheel Speed Sensor

Y026787: 006: EN: Released: Fri Nov 11 11:18:50 CET 2016:

Knorr-Bremse Group

Doc. No. Y250903 (EN - Rev. 000)

July 2016

Knorr-Bremse Systeme für Nutzfahrzeuge GmbH .Moosacher Straße 80 .80809 Munich .Germany .Tel:+49 89 3547-0 .Fax: +49 89 3547-2767 .www.knorr-bremse.com .www.knorr-bremseCVS.com

Commercial Vehicle Systems

Safety and Environmental Guidelines

Note: The safety advice listed below is applicable to general service and diagnostic work on braking systems. Also

observe any recommendations from the axle or vehicle manufacturer concerning towing, jacking-up and securing

the vehicle.

CAUTION: KNORR-BREMSE IS NOT LIABLE FOR ANY INJURIES OR DAMAGES CAUSED BY IMPROPER USE

OF SPECIFIED SERVICE KITS AND/OR SERVICE TOOLS. FURTHERMORE, MISUSE OF TOOLS OR INCORRECT

INSTALLATION OR APPLICATION OF SERVICE KITS MAY RESULT IN DAMAGE OR POTENTIALLY UNSAFE

VEHICLE OPERATIONS. IN THIS CASE, KNORR-BREMSE DOES NOT HAVE ANY WARRANTY OBLIGATIONS.

Before and during working on or around compressed air systems and devices, the following precautions

should be observed:

1 Always wear safety glasses when working with air pressure.

2 Never exceed the vehicle manufacturer’s recommended air pressures.

3 Never look into air jets or direct them at anyone.

4 Never connect or disconnect a hose or line containing pressure; it may whip as air escapes.

5 When removing or servicing a product, ensure all pressure related to the speciﬁc system it is contained in has

been depleted to 0 bar. Be aware that if the vehicle is equipped with an air dryer system, it can also contain air

pressure along with its purge reservoir, if ﬁtted, even after pressure has been drained from the other reservoirs.

6 If it is necessary to drain the air pressure from reservoirs, etc., keep away from brake actuator push rods and

levers since they may move as system pressure drops. On vehicles ﬁtted with air suspension, it is advised when

undertaking such work, to support the chassis from sudden lowering and therefore prevent any possibility of

being trapped between the chassis and axle or ground.

7 Park the vehicle on a level surface, apply the parking brakes, and always chock the wheels as depleting vehicle

air system pressure may cause the vehicle to roll.

8 When working under or around the vehicle, and particularly when working in the engine compartment, the

engine should be shut off and the ignition key removed. Where circumstances require that the engine be running,

EXTREME CAUTION should be taken to prevent personal injury resulting from contact with moving, rotating,

leaking, heated or electrically charged components. Additionally, it is advisable to place a clear sign on or near

the steering wheel advising that there is work in progress on the vehicle.

9 When working on vehicles equipped with air suspension, to guard against injury due to unexpected downward

movement of the chassis caused by sudden pressure loss in the suspension system, ensure that the vehicle

chassis is mechanically supported with a ‘prop’ between the chassis and the axle or between the chassis and

the ground.

10 Examine all pipework for signs of kinks, dents, abrasion, drying out or overheating. Be aware that kinks in

pipework may result in air pressure being trapped in the pipework and associated equipment. Replacement

hardware, tubing, hose, ﬁttings, etc. must be of equivalent size, type and strength as original equipment and

be designed speciﬁcally for such applications and systems. Check the attachment of all pipework; it should be

installed so that it cannot abrade or be subjected to excessive heat.

11 Components with stripped threads or damaged/corroded parts must be replaced completely. Do not attempt

repairs requiring machining or welding unless speciﬁcally stated and approved by the vehicle or component

manufacturer.

12 Never attempt to install, remove, disassemble or assemble a device until you have read and thoroughly

understood the recommended procedures. Some units contain powerful springs and injury can result if not

properly dismantled and reassembled. Use only the correct tools and observe all precautions pertaining to use

of those tools.

Y026787: 006: EN: Released: Fri Nov 11 11:18:50 CET 2016:

Knorr-Bremse Group

Knorr-Bremse Systeme für Nutzfahrzeuge GmbH .Moosacher Straße 80 .80809 Munich .Germany .Tel:+49 89 3547-0 .Fax: +49 89 3547-2767 .www.knorr-bremse.com .www.knorr-bremseCVS.com

Doc. No. Y250903 (EN - Rev. 000)

July 2016

Revision Details

Rev. 000 July 2016 New document

Safety and Environmental Guidelines

13 Before removing any device note its position and the connections of all pipework so that the replacement/

serviced device can be properly installed. Ensure that adequate support or assistance is provided for the removal/

installation of heavy items.

14 Only use genuine replacement parts, components and kits as supplied by Knorr-Bremse or the vehicle

manufacturer. Only use the recommended tools as speciﬁed in related Knorr-Bremse instructions.

15 The serviced or replaced product must be checked for correct function and effectiveness.

16 If products have been dismantled, serviced or replaced, whose performance could affect braking performance

or system behaviour, this should be checked on a roller dynamometer. Bear in mind that a lower performance

may be experienced during the bedding-in phase if new brake pads/linings and/or brake discs/drums have been

ﬁtted.

17 The use of impact screwdrivers or impact wrenches in conjunction with Knorr-Bremse service tools for air disc

brakes is not permitted. The service tools are not designed for such use. It is likely that the tools or the vehicle

will be damaged and there is a serious risk of injury – see Caution on previous page.

18 Do not use compressed air to clean the disc brake. Avoid air contamination of brake dust.

19 Prior to returning the vehicle to service, make certain that all components and the complete brake systems are

leak free and restored to their proper operating condition.

Welding

To avoid damage to electronic components when carrying out electrical welding, the following precautions should

be observed:

1 In all cases, before starting any electrical welding, remove all connections from any electronic control units or

modules, noting their position and the order in which they are removed.

2 When re-inserting the electrical connectors (in reverse order) it is essential that they are ﬁtted to their correct

assigned position - if necessary this must be checked by PC Diagnostics.

Disposal of Waste Equipment by Business Users in the European Union

This symbol on the product, packaging or in user instructions, indicates that this product must not

be disposed of with other general waste. Instead, it is your responsibility to dispose of the waste

electrical and electronic parts of this product by handing them over to a company or organisation

authorised for the recycling of waste electrical and electronic equipment. For more information about

arrangements for waste equipment disposal please contact your Knorr-Bremse distributor or local

Knorr-Bremse representative.

See Y075876 for latest revision.

Y026787: 006: EN: Released: Fri Nov 11 11:18:50 CET 2016:

Knorr-Bremse Group

Doc. No. Y251073 (EN - Rev. 000)

July 2016

Knorr-Bremse Systeme für Nutzfahrzeuge GmbH .Moosacher Straße 80 .80809 Munich .Germany .Tel:+49 89 3547-0 .Fax: +49 89 3547-2767 .www.knorr-bremse.com .www.knorr-bremseCVS.com

Contents

Commercial Vehicle Systems

Title Doc. No. PD No.

KB4TA System Overview Y250904 PD-203-400

KB4TA D System Overview Y250905 PD-203-500

KB4TA ABS Module Y250906 PD-203-430

KB4TA D ABS ECU Y250907 PD-203-530

KB4TA/KB4TA D System Components Y250908 PD-203-360

KB4TA/KB4TA D Cables Y250909 PD-203-380

KB4TA/KB4TA D System Diagnostics Y250910 PD-203-390

KB4TA System Diagrams Y250911 PD-203-480

KB4TA D System Diagrams Y250913 PD-203-580

Y026787: 006: EN: Released: Fri Nov 11 11:18:50 CET 2016:

Knorr-Bremse Group

Doc. No. Y251073 (EN - Rev. 000)

July 2016

Knorr-Bremse Systeme für Nutzfahrzeuge GmbH .Moosacher Straße 80 .80809 Munich .Germany .Tel:+49 89 3547-0 .Fax: +49 89 3547-2767 .www.knorr-bremse.com .www.knorr-bremseCVS.com

Contents

Product Manual

Revision Details

Rev. 000 July 2016 New document.

Y026787: 006: EN: Released: Fri Nov 11 11:18:50 CET 2016:

1Knorr-Bremse Group

PD-203-400

The information contained herein is subject to alteration without notice and therefore may not be the latest release. Please check our website www.knorr-bremseCVS.com for the latest update or contact your local Knorr-Bremse representative.

The ﬁgurative mark “K” and the trademarks KNORR and KNORR-BREMSE are registered in the name of Knorr-Bremse AG. Additional terms and conditions apply; please refer to our website knorr-bremseCVS.com for full Disclaimer.

Note: If service work is carried out on a vehicle based on information provided herein, it is the responsibility of the workshop to ensure the vehicle is fully tested and in full

functional order before the vehicle is returned into service. Knorr-Bremse accepts no liability for problems caused as a result of appropriate tests not being carried out.

Knorr-Bremse Systeme für Nutzfahrzeuge GmbH .Moosacher Straße 80 .80809 Munich .Germany .Tel:+49 89 3547-0 .Fax: +49 89 3547-2767 .www.knorr-bremse.com .www.knorr-bremseCVS.com

DATA

Product

Commercial Vehicle Systems

KB4TA System Overview

Doc. No. Y250904 (EN - Rev. 000)

July 2016

The Knorr-Bremse KB4TA module ES1305 (see

PD-203-430, Document No. Y250908) is an integrated

ABS electronic control unit and dual modulator valve for

air braked trailers with mechanical or air suspension.

KB4TA is designed to work in trailer systems powered

via ISO 7638 but the addition of ISO 1185 stop lamp

powering is included as standard as a safety feature so,

in the event that there is no ISO 7638 powering, the ABS

function is maintained.

Note: Stop lamp powering should only be considered

as a backup in the event of failure of the ISO 7638

connection.

The KB4TA module is designed for all normal system

variants from 2S/2M up to 4S/3M. The conﬁguration

as supplied is 2S/2M, but with the integrated

auto-conﬁguration the module detects additional sensors and adjusts upward to 4S/2M automatically.

Other conﬁgurations and additional functions can be quickly and effectively achieved using PC Software

ECUtalk®. For 4S/3M applications an additional external (third) ABS modulator is necessary (see

PD 203-360, Document No. Y250908).

The KB4TA brake system is capable of working with drum brake or disc brakes and the systems shown below are

only typical. For more systems see PD-203-480, Document No. Y250911.

Function

KB4TA System diagram (2S/2M) for semi-trailer with air suspension and disc brakes

Legend:

1 Coupling Head with Filter -

“Supply”

2 Coupling Head with Filter -

“Control”

3 ABS Connector ISO 7638

4 Park / Shunt Valve with

Emergency Function and integral

Charging Valve

5 Air Reservoir

6 Drain Valve

7 Load Sensing Valve

8 ABS Module with 6 delivery

ports

9 Brake Chamber

10 Spring Brake

11 Sensing Ring and Wheel Speed

Sensor

12 Air Spring Bellow

13 Levelling Valve

14 Test Connector

15 Electrical Connector “Lighting”

acc. to ISO 1185

sys_dia_001

Y026787: 006: EN: Released: Fri Nov 11 11:18:50 CET 2016:

Knorr-Bremse Group

PD-203-400

Doc. No. Y250904 (EN - Rev. 000)

July 2016

Note: If service work is carried out on a vehicle based on information provided herein, it is the responsibility of the workshop to ensure the vehicle is fully tested and in full

functional order before the vehicle is returned into service. Knorr-Bremse accepts no liability for problems caused as a result of appropriate tests not being carried out.

Knorr-Bremse Systeme für Nutzfahrzeuge GmbH .Moosacher Straße 80 .80809 Munich .Germany .Tel:+49 89 3547-0 .Fax: +49 89 3547-2767 .www.knorr-bremse.com .www.knorr-bremseCVS.com

KB4TA System Overview

Product Data

KB4TA System diagram (2S/2M) for semi-trailer with mechanical suspension and drum brakes

SERVICE

PARKING 12

SERVICE

PARKING 12

SERVICE

PARKING 12

SERVICE

PARKING 12

sys_dia_002

Legend:

1 Coupling Head with Filter -

“Supply”

2 Coupling Head with Filter -

“Control”

3 ABS Connector ISO 7638

4 Park / Shunt Valve with

Emergency Function

5 Air Reservoir

6 Drain Valve

7 Load Sensing Valve

8 ABS Module with 6 delivery

ports

9 Brake Chamber

10 Spring Brake

11 Sensing Ring and Wheel Speed

Sensor

14 Test Connector

15 Electrical Connector “Lighting”

acc. to ISO 1185

Power up Sequence

At power up, the KB4TA module performs a series of self-checks that can assist a technician to determine the ABS

system status and conﬁguration.

Trailer ABS Warning Lamp

At power up (when no faults are detected) the trailer ABS warning lamp in the towing vehicle will turn on for

approximately 2 seconds as a bulb check and then turn off. If a fault has been detected the bulb will remain on. The

same warning lamp sequence is produced by the trailer mounted headboard warning lamp (when installed)

Modulator ‘Chuff Test’ at Power up

At power up, the KB4TA module activates a modulator ‘chuff test’. This electrical and pneumatic ABS modulator test

can help the technician identify problems with modulator installations and/or wiring.

With brake pressure applied, a properly installed modulator will generate ﬁve rapid audible ‘chuffs’ of air pressure on

the left internal modulator followed by ﬁve ‘chuffs’ on the right modulator. There will then be ﬁve further ‘chuffs’ on

the additional axle modulator if ﬁtted .

If the modulator is wired incorrectly, the modulator will only produce one ‘chuff’, or no ‘chuffs’ at all. If a fault is

detected during the modulator ‘chuff test’, compare the wiring and piping to the electrical system schematic and

make any necessary alterations.

System Description

Y026787: 006: EN: Released: Fri Nov 11 11:18:50 CET 2016:

3Knorr-Bremse Group

PD-203-400

Doc. No. Y250904 (EN - Rev. 000)

July 2016

Note: If service work is carried out on a vehicle based on information provided herein, it is the responsibility of the workshop to ensure the vehicle is fully tested and in full

functional order before the vehicle is returned into service. Knorr-Bremse accepts no liability for problems caused as a result of appropriate tests not being carried out.

Knorr-Bremse Systeme für Nutzfahrzeuge GmbH .Moosacher Straße 80 .80809 Munich .Germany .Tel:+49 89 3547-0 .Fax: +49 89 3547-2767 .www.knorr-bremse.com .www.knorr-bremseCVS.com

KB4TA System Overview

Commercial Vehicle Systems

Operation

KB4TA provides basic service braking in addition to the ABS function.

ABS Operation

The KB4TA moduleis used to prevent the wheels of a trailer locking whilst braking. The friction between the tyre and

the road is created by relative movement between their two surfaces, i.e. difference in surface speeds of road and

tyre and is referred to as ‚slip‘. It is well known that a wheel operating on a wet surface has reduced friction (adhesion)

and hence can transmit reduced braking effort to the road.

The KB4TA module constantly monitors the rotational speed of all sensed wheels on the trailer by using the wheel

speed sensor outputs. It then calculates an average of these wheel speeds (Reference Speed) and constantly

compares it with the speed of each wheel.

During braking, if one or more wheels is on a slippery surface and is unable to support the level of braking that it

is being asked to contribute, the wheel speed will drop relative to the Reference Speed, i.e. there will be ‘slip’, and

deceleration of that wheel will increase. The KB4TA module will normally detect this during the application of the

brake and, before the wheel becomes locked, send an electrical signal to the appropriate modulator to reduce the

pressure in the service brake actuator(s) on that wheel or group of wheels. Once the wheel starts to accelerate

and the slip is reduced, the KB4TA module will send an electrical signal to the modulator to gradually increase the

pressure until either the wheel again starts decelerating or the requested level of braking is reached. It is therefore

possible to maximise the utilisation of the available adhesion to improve stopping distance whilst maintaining stability.

Normal Braking

During normal braking, the KB4TA module system operates as two standard relay valves in parallel. If the ECU

does not detect excessive wheel slip, ABS control will remain inactive while the vehicle is braked according to driver

demand.

Odometer Function

Odometer

The KB4TA module has an odometer function to provide a means of storing the accumulated mileage of the trailer.

The mileage is computed by utilizing information calculated from the wheel speed sensors. This feature will accurately

store mileage information up to 1,000,000 km. The accuracy of readings higher than this cannot be guaranteed. The

mileage can be displayed using PC diagnostics ECUtalk®or through blink codes.

Trip Counter

The KB4TA module provides a counter to record the trip mileage. The feature is accessed through PC diagnostics

ECUtalk®.

Service Interval

The KB4TA module provides a feature that can be used to indicate a service interval for the trailer. The service interval

can be accessed via PC diagnostics ECUtalk®. If conﬁgured, the KB4TA module can ﬂash the warning lamp when

the vehicle is at standstill and the ABS is ﬁrst powered to indicate when the service interval has been exceeded.

Conﬁguration of the KB4TA Module.

Y026787: 006: EN: Released: Fri Nov 11 11:18:50 CET 2016:

Knorr-Bremse Group

PD-203-400

Doc. No. Y250904 (EN - Rev. 000)

July 2016

Note: If service work is carried out on a vehicle based on information provided herein, it is the responsibility of the workshop to ensure the vehicle is fully tested and in full

functional order before the vehicle is returned into service. Knorr-Bremse accepts no liability for problems caused as a result of appropriate tests not being carried out.

Knorr-Bremse Systeme für Nutzfahrzeuge GmbH .Moosacher Straße 80 .80809 Munich .Germany .Tel:+49 89 3547-0 .Fax: +49 89 3547-2767 .www.knorr-bremse.com .www.knorr-bremseCVS.com

KB4TA System Overview

Product Data

Conﬁguration of the KB4TA Module

ABS Auto Conﬁguration

When manufactured the KB4TA module has a default ABS conﬁguration of 2S/2M. If the ABS conﬁguration has not

been manually set using the diagnostic tool ECUtalk®then, at power up, if the KB4TA detects additional sensors

it will perform an auto-conﬁguration. An auto-conﬁguration only adjusts upward (e.g. from 2S/2M to 4S/2M). A

conﬁguration will not be accepted if a wheel speed signal is generated at the time of conﬁguration.

A 4S/3M conﬁguration cannot be realised automatically, this requires manual conﬁguration with the diagnostic tool

ECUtalk®.

ABS manual Conﬁguration

Depending upon the required ABS conﬁguration it may be necessary to use the diagnostic tool ECUtalk®to manually

conﬁgure the KB4TA module, i.e. 4S/3M ABS conﬁguration.

Once manually conﬁgured, the KB4TA module will no longer auto-conﬁgure, unless the “Reset ABS Conﬁguration”

option is used in the diagnostic tool ECUtalk®.

Auxiliary Conﬁguration

The KB4TA module supports the conﬁguration of auxiliary functions on AUXIO1 and AUXIO2 using the diagnostic

tool ECUtalk®. However, the associated pins can only be conﬁgured as AUXIO if they are not already conﬁgured as

4S/3M and stop lamp power respectively.

Part number K004246 (ES1305) will only allow the AUXIO to be conﬁgured as headboard warning light, 24V (Power

Supply) or OFF.

Part number K004236 (ES1305) will allow the AUXIO to be conﬁgured as headboard warning light, 24V (Power

Supply), RtR, ISS, ABS Active or OFF.

Both part numbers additionally support conﬁguration of the AUXIO as Pad Wear inputs.

Non Standard Tyre Sizes

The KB4TA module allows for tyre rolling radius and sensing ring tooth count parameters to be set for each axle

using a diagnostic tool ECUtalk®. This setting is necessary for the module to accurately calculate the vehicle speed

and determine the odometer mileage. Wheels of the same axle must be set to the same rolling radius and sensing

ring tooth count. In most cases, these parameters are set by the trailer OEM and do not need to be adjusted. In the

case of a service replacement unit, always check that these parameters are set to match the vehicle. Refer to the

manufacturer’s tyre speciﬁcation for correct values. Sensing ring tooth count is defaulted to 100 teeth, but can be

adjusted between 60 and 120 teeth.

Y026787: 006: EN: Released: Fri Nov 11 11:18:50 CET 2016:

5Knorr-Bremse Group

PD-203-400

Doc. No. Y250904 (EN - Rev. 000)

July 2016

Note: If service work is carried out on a vehicle based on information provided herein, it is the responsibility of the workshop to ensure the vehicle is fully tested and in full

functional order before the vehicle is returned into service. Knorr-Bremse accepts no liability for problems caused as a result of appropriate tests not being carried out.

Knorr-Bremse Systeme für Nutzfahrzeuge GmbH .Moosacher Straße 80 .80809 Munich .Germany .Tel:+49 89 3547-0 .Fax: +49 89 3547-2767 .www.knorr-bremse.com .www.knorr-bremseCVS.com

KB4TA System Overview

Commercial Vehicle Systems

Error Detection

The KB4TA module contains self-testing diagnostic circuitry that monitors the ABS components and wiring. When

the module senses an erroneous system condition, it activates the trailer ABS warning lamp in the towing vehicle

(and headboard if installed), disables all or part of the ABS functions and stores the error in memory as a Diagnostic

Trouble Code (DTC).

For some trouble codes, the KB4TA module will automatically reset and clear the “active” DTC once the error has

been corrected. When an “active” DTC is cleared automatically, the error remains stored in memory as an „inactive“

DTC and can be viewed using blink code diagnostics or ECUtalk®. However repeated occurrences of certain errors

will result in the DTC being “latched” which means the error remains “active” even if the condition is only intermittent.

Once the code is latched, a manual reset will be necessary. After the problem is resolved, trouble codes can be

deleted using the diagnostic tool ECUtalk®.

ABS Shutdown

Depending on the detected error and the ABS conﬁguration the ECU will either partially or totally disable the ABS

function as follows:

• 2S/2M conﬁgurations: total shut down.

• 4S/2M conﬁgurations: Reduce to 2S/2M

• 4S/3M conﬁgurations: Reduce to 2S/2M.

The above shutdown modes are dependent on the type and location of the detected error. For more information see

ABS Electronics Information Document Y023867. In all cases a warning signal will be transmitted to illuminate the

trailer ABS warning lamp which will remain “ON” as long as the ignition is in the “RUN” position. In cases where the

ABS is completely disabled, the vehicle reverts to normal braking (without ABS intervention).

ABS faults should be rectiﬁed at the earliest opportunity.

ECU Errors

If an ECU related problem is detected the ABS function is disabled while normal brake control remains available.

Low and High Voltage Operation

Should the supply voltage to the ECU be outside the deﬁned voltage range (18 to 32V) the ABS function is disabled

while normal brake control remains available.

For further information on diagnostics see PD-203-390, Document No. Y250910.

Y026787: 006: EN: Released: Fri Nov 11 11:18:50 CET 2016:

Knorr-Bremse Group

PD-203-400

Doc. No. Y250904 (EN - Rev. 000)

July 2016

Note: If service work is carried out on a vehicle based on information provided herein, it is the responsibility of the workshop to ensure the vehicle is fully tested and in full

functional order before the vehicle is returned into service. Knorr-Bremse accepts no liability for problems caused as a result of appropriate tests not being carried out.

Knorr-Bremse Systeme für Nutzfahrzeuge GmbH .Moosacher Straße 80 .80809 Munich .Germany .Tel:+49 89 3547-0 .Fax: +49 89 3547-2767 .www.knorr-bremse.com .www.knorr-bremseCVS.com

KB4TA System Overview

Product Data

Revision Details

Rev. 000 July 2016 New document.

Other Documentation

• KB4TA Trailer anti-lock braking system test report (RDW-20160001)

• KB4TA ABS Information document (Y023866)

• KB4TA Electronics Information document (Y023867)

• Installation Instructions “Wiring/Harness, Modular System” (Y011788)

Y026787: 006: EN: Released: Fri Nov 11 11:18:50 CET 2016:

1Knorr-Bremse Group

PD-203-500

Note: If service work is carried out on a vehicle based on information provided herein, it is the responsibility of the workshop to ensure the vehicle is fully tested and in full

functional order before the vehicle is returned into service. Knorr-Bremse accepts no liability for problems caused as a result of appropriate tests not being carried out.

Knorr-Bremse Systeme für Nutzfahrzeuge GmbH .Moosacher Straße 80 .80809 Munich .Germany .Tel:+49 89 3547-0 .Fax: +49 89 3547-2767 .www.knorr-bremse.com .www.knorr-bremseCVS.com

DATA

Product

Commercial Vehicle Systems

KB4TA D System Overview

Doc. No. Y250905 (EN - Rev. 000)

July 2016

The Basic Knorr-Bremse KB4TA D brake system

comprises a KB4TA D ECU ES1220 (see PD-203-530,

Document No. Y250907) plus two ABS Modulator

Valves (see PD-203-360, Document No. Y250908) and

is designed for air braked trailers with mechanical or air

suspension.

KB4TA D is designed to work in trailer systems powered

via ISO 7638 but the addition of ISO 1185 stop lamp

powering is included as standard as a safety feature so,

in the event that there is no ISO 7638 powering, the ABS

function is maintained.

Note: Stop lamp powering should only be considered

as a backup in the event of failure of the ISO 7638

connection.

The KB4TA D ECU is designed for all normal

system variants from 2S/2M up to 4S/3M. The conﬁguration as supplied is 2S/2M, but with the integrated

auto-conﬁguration the ECU detects additional sensors and adjusts upward to 4S/2M automatically.

Other conﬁgurations and additional functions can be quickly and effectively achieved using PC Software

ECUtalk®. For 4S/3M applications an additional external (third) ABS modulator is necessary (see

PD 203-360, Document No. Y250908).

The KB4TA D brake system is capable of working with drum brake or disc brakes and the systems shown below are

only typical. For more systems see PD-203-580, Document No. Y250913.

Function

KB4TA D System diagram (2S/2M) for semi-trailer with air suspension and disc brakes

(ECU mounted above centre of bogie)

Legend:

1 Coupling Head with Filter -

“Supply”

2 Coupling Head with Filter -

“Control”

3 ABS Connector ISO 7638

4 Park / Shunt Valve with

Emergency Function and

integral Charging Valve

5 Air Reservoir

6 Drain Valve

7 Load Sensing Valve

8a ABS ECU

8b ABS Relay Modulator Valve

9 Brake Chamber

10 Spring Brake

11 Sensing Ring and Wheel Speed

Sensor

12 Air Spring Bellow

13 Levelling Valve

14 Test Connector

15 Electrical Connector “Lighting”

acc. to ISO 1185

kb4tad_sys_001

Y026787: 006: EN: Released: Fri Nov 11 11:18:50 CET 2016:

Knorr-Bremse Group

PD-203-500

Doc. No. Y250905 (EN - Rev. 000)

July 2016

Note: If service work is carried out on a vehicle based on information provided herein, it is the responsibility of the workshop to ensure the vehicle is fully tested and in full

functional order before the vehicle is returned into service. Knorr-Bremse accepts no liability for problems caused as a result of appropriate tests not being carried out.

Knorr-Bremse Systeme für Nutzfahrzeuge GmbH .Moosacher Straße 80 .80809 Munich .Germany .Tel:+49 89 3547-0 .Fax: +49 89 3547-2767 .www.knorr-bremse.com .www.knorr-bremseCVS.com

KB4TA D System Overview

Product Data

Legend:

1 Coupling Head with Filter -

“Supply”

2 Coupling Head with Filter -

“Control”

3 ABS-Connector ISO 7638

4 Park-/Shunt Valve with

EmergencyFunction

5 Air Reservoir

6 Drain Valve

7 Load Sensing Valve

8a ABS ECU

8b ABS Relay Modulator Valve

9 Brake Chamber

10 Spring Brake

11 Sensing Ring and Wheel Speed

Sensor

14 Test Connector

15 Electrical Connector “Lighting”

acc. to ISO 1185

KB4TA D System diagram (2S/2M) for semi-trailer with mechanical suspension and drum brakes

(ECU mounted at front of trailer)

SERVICE

PARKING 12

SERVICE

PARKING 12

SERVICE

PARKING 12

SERVICE

PARKING 12

kb4tad_sys__002

414

910

Power up Sequence

At power up, the KB4TA D ECU performs a series of self-checks that can assist a technician to determine the ABS

system status and conﬁguration.

Trailer ABS Warning Lamp

At power up (when no faults are detected) the trailer ABS warning lamp in the towing vehicle will turn on for

approximately 2 seconds as a bulb check and then turn off. If a fault has been detected the bulb will remain on. The

same warning lamp sequence is produced by the trailer mounted headboard warning lamp (when installed)

Modulator ‘Chuff Test’ at Power up

At power up, the KB4TA D ECU activates a modulator ‘chuff test’. This electrical and pneumatic ABS modulator test

can help the technician identify problems with modulator installations and/or wiring.

With brake pressure applied, a properly installed modulator will generate ﬁve rapid audible ‘chuffs’ of air pressure on

the left internal modulator followed by ﬁve ‘chuffs’ on the right modulator. There will then be ﬁve further ‘chuffs’ on

the additional axle modulator if ﬁtted .

If the ECU is wired incorrectly, the modulator will only produce one ‘chuff’, or no ‘chuffs’ at all. If a fault is detected

during the modulator ‘chuff test’, compare the wiring and piping to the electrical system schematic and make any

necessary alterations.

System Description

Y026787: 006: EN: Released: Fri Nov 11 11:18:50 CET 2016:

3Knorr-Bremse Group

PD-203-500

Doc. No. Y250905 (EN - Rev. 000)

July 2016

Note: If service work is carried out on a vehicle based on information provided herein, it is the responsibility of the workshop to ensure the vehicle is fully tested and in full

functional order before the vehicle is returned into service. Knorr-Bremse accepts no liability for problems caused as a result of appropriate tests not being carried out.

Knorr-Bremse Systeme für Nutzfahrzeuge GmbH .Moosacher Straße 80 .80809 Munich .Germany .Tel:+49 89 3547-0 .Fax: +49 89 3547-2767 .www.knorr-bremse.com .www.knorr-bremseCVS.com

KB4TA D System Overview

Commercial Vehicle Systems

Operation

KB4TA D provides basic service braking in addition to the ABS function.

ABS Operation

The KB4TA D ECU is used to prevent the wheels of a trailer locking whilst braking. The friction between the tyre and

the road is created by relative movement between their two surfaces, i.e. difference in surface speeds of road and

tyre and is referred to as ‚slip‘. It is well known that a wheel operating on a wet surface has reduced friction (adhesion)

and hence can transmit reduced braking effort to the road.

The KB4TA D ECU constantly monitors the rotational speed of all sensed wheels on the trailer by using the wheel

speed sensor outputs. It then calculates an average of these wheel speeds (Reference Speed) and constantly

compares it with the speed of each wheel.

During braking, if one or more wheels is on a slippery surface and is unable to support the level of braking that it

is being asked to contribute, the wheel speed will drop relative to the Reference Speed, i.e. there will be ‘slip’, and

deceleration of that wheel will increase. The KB4TA D ECU will normally detect this during the application of the

brake and, before the wheel becomes locked, send an electrical signal to the appropriate modulator to reduce the

pressure in the service brake actuator(s) on that wheel or group of wheels. Once the wheel starts to accelerate and

the slip is reduced, the KB4TA D ECU will send an electrical signal to the modulator to gradually increase the pressure

until either the wheel again starts decelerating or the requested level of braking is reached. It is therefore possible to

maximise the utilisation of the available adhesion to improve stopping distance whilst maintaining stability.

Normal Braking

During normal braking, the KB4TA D ECU system operates as two standard relay valves in parallel. If the ECU

does not detect excessive wheel slip, ABS control will remain inactive while the vehicle is braked according to driver

demand.

Odometer Function

Odometer

The KB4TA D ECU has an odometer function to provide a means of storing the accumulated mileage of the trailer.

The mileage is computed by utilizing information calculated from the wheel speed sensors. This feature will accurately

store mileage information up to 1,000,000 km. The accuracy of readings higher than this cannot be guaranteed. The

mileage can be displayed using PC diagnostics ECUtalk®or through blink codes.

Trip Counter

The KB4TA D ECU provides a counter to record the trip mileage. The feature is accessed through PC diagnostics

ECUtalk®.

Service Interval

The KB4TA D ECU provides a feature that can be used to indicate a service interval for the trailer. The service interval

can be accessed via PC diagnostics ECUtalk®. If conﬁgured, the KB4TA D ECU can ﬂash the warning lamp when

the vehicle is at standstill and the ABS is ﬁrst powered to indicate when the service interval has been exceeded.

Conﬁguration of the KB4TA D ECU

Y026787: 006: EN: Released: Fri Nov 11 11:18:50 CET 2016:

Knorr-Bremse Group

PD-203-500

Doc. No. Y250905 (EN - Rev. 000)

July 2016

Note: If service work is carried out on a vehicle based on information provided herein, it is the responsibility of the workshop to ensure the vehicle is fully tested and in full

functional order before the vehicle is returned into service. Knorr-Bremse accepts no liability for problems caused as a result of appropriate tests not being carried out.

Knorr-Bremse Systeme für Nutzfahrzeuge GmbH .Moosacher Straße 80 .80809 Munich .Germany .Tel:+49 89 3547-0 .Fax: +49 89 3547-2767 .www.knorr-bremse.com .www.knorr-bremseCVS.com

KB4TA D System Overview

Product Data

Conﬁguration of the KB4TA D ECU

ABS Auto Conﬁguration

When manufactured the KB4TA D ECU has a default ABS conﬁguration of 2S/2M. If the ABS conﬁguration has not

been manually set using the diagnostic tool ECUtalk®then, at power up, if the KB4TA D detects additional sensors

it will perform an auto-conﬁguration. An auto-conﬁguration only adjusts upward (e.g. from 2S/2M to 4S/2M). A

conﬁguration will not be accepted if a wheel speed signal is generated at the time of conﬁguration.

A 4S/3M conﬁguration cannot be realised automatically, this requires manual conﬁguration with the diagnostic tool

ECUtalk®.

ABS manual Conﬁguration

Depending upon the required ABS conﬁguration it may be necessary to use the diagnostic tool ECUtalk®to manually

conﬁgure the KB4TA D ECU, i.e. 4S/3M ABS conﬁguration.

Once manually conﬁgured, the KB4TA D ECU will no longer auto-conﬁgure, unless the “Reset ABS Conﬁguration”

option is used in the diagnostic tool ECUtalk®.

Auxiliary Conﬁguration

The KB4TA D ECU supports the conﬁguration of auxiliary functions on AUXIO1 and AUXIO2 using the diagnostic

tool ECUtalk®. However, the associated pins can only be conﬁgured as AUXIO if they are not already conﬁgured as

4S/3M and stop lamp power respectively.

Non Standard Tyre Sizes

The KB4TA D ECU allows for tyre rolling radius and sensing ring tooth count parameters to be set for each axle

using a diagnostic tool ECUtalk®. This setting is necessary for the ECU to accurately calculate the vehicle speed

and determine the odometer mileage. Wheels of the same axle must be set to the same rolling radius and sensing

ring tooth count. In most cases, these parameters are set by the trailer OEM and do not need to be adjusted. In the

case of a service replacement unit, always check that these parameters are set to match the vehicle. Refer to the

manufacturer’s tyre speciﬁcation for correct values. Sensing ring tooth count is defaulted to 100 teeth, but can be

adjusted between 60 and 120 teeth.

Y026787: 006: EN: Released: Fri Nov 11 11:18:50 CET 2016:

5Knorr-Bremse Group

PD-203-500

Doc. No. Y250905 (EN - Rev. 000)

July 2016

Note: If service work is carried out on a vehicle based on information provided herein, it is the responsibility of the workshop to ensure the vehicle is fully tested and in full

functional order before the vehicle is returned into service. Knorr-Bremse accepts no liability for problems caused as a result of appropriate tests not being carried out.

Knorr-Bremse Systeme für Nutzfahrzeuge GmbH .Moosacher Straße 80 .80809 Munich .Germany .Tel:+49 89 3547-0 .Fax: +49 89 3547-2767 .www.knorr-bremse.com .www.knorr-bremseCVS.com

KB4TA D System Overview

Commercial Vehicle Systems

Error Detection

The KB4TA D ECU contains self-testing diagnostic circuitry that monitors the ABS components and wiring. When

the ECU senses an erroneous system condition, it activates the trailer ABS warning lamp in the towing vehicle (and

headboard if installed), disables all or part of the ABS functions and stores the error in memory as a Diagnostic

Trouble Code (DTC).

For some trouble codes, the KB4TA D ECU will automatically reset and clear the “active” DTC once the error has

been corrected. When an “active” DTC is cleared automatically, the error remains stored in memory as an „inactive“

DTC and can be viewed using blink code diagnostics or ECUtalk®. However repeated occurrences of certain errors

will result in the DTC being “latched” which means the error remains “active” even if the condition is only intermittent.

Once the code is latched, a manual reset will be necessary. After the problem is resolved, trouble codes can be

deleted using the diagnostic tool ECUtalk®.

ABS Shutdown

Depending on the detected error and the ABS conﬁguration the ECU will either partially or totally disable the ABS

function as follows:

• 2S/2M conﬁgurations: total shut down.

• 4S/2M conﬁgurations: Reduce to 2S/2M

• 4S/3M conﬁgurations: Reduce to 2S/2M.

The above shutdown modes are dependent on the type and location of the detected error. For more information see

ABS Electronics Information Document Y023867. In all cases a warning signal will be transmitted to illuminate the

trailer ABS warning lamp which will remain “ON” as long as the ignition is in the “RUN” position. In cases where the

ABS is completely disabled, the vehicle reverts to normal braking (without ABS intervention).

ABS faults should be rectiﬁed at the earliest opportunity.

ECU Errors

If an ECU related problem is detected the ABS function is disabled while normal brake control remains available.

Low and High Voltage Operation

Should the supply voltage to the ECU be outside the deﬁned voltage range (18 to 32V) the ABS function is disabled

while normal brake control remains available.

For further information on diagnostics see PD-203-390, Document No. Y250910.

Y026787: 006: EN: Released: Fri Nov 11 11:18:50 CET 2016:

Knorr-Bremse Group

PD-203-500

Doc. No. Y250905 (EN - Rev. 000)

July 2016

Note: If service work is carried out on a vehicle based on information provided herein, it is the responsibility of the workshop to ensure the vehicle is fully tested and in full

functional order before the vehicle is returned into service. Knorr-Bremse accepts no liability for problems caused as a result of appropriate tests not being carried out.

Knorr-Bremse Systeme für Nutzfahrzeuge GmbH .Moosacher Straße 80 .80809 Munich .Germany .Tel:+49 89 3547-0 .Fax: +49 89 3547-2767 .www.knorr-bremse.com .www.knorr-bremseCVS.com

KB4TA D System Overview

Product Data

Revision Details

Rev. 000 July 2016 New document.