BENDIX EC-14 ANTILOCK CONTROLLER User manual

1
®
SD-13-4784
Bendix®EC-14™AntiLock Controller Assembly
FIGURE 1 - EC-14™ANTILOCK CONTROLLER ASSEMBLY
DESCRIPTION
GENERAL
Bendix trailer antilock systems utilizing the EC-14™
electroniccontrollerassemblyprovideaxle braking control
for buses, trucks, and truck trailers. By controlling "wheel
lock-up"duringaggressivebraking,thetrailer retains ahigh
degreeof stabilityandsteerabilitywhilebraking, andvehicle
stoppingdistancemaybereduced.
Inordertoprovideaxlecontrolantilock,theEC-14™controller
is used in combination with the following components:
•Fourindividualwheel speed sensors.
•Onecombination modulator-relayvalve.
•Onestand alonemodulatorvalve.
•Antilockconditionlamp(dashmounted).
PHYSICAL
TheEC-14™controllerelectronics,whichregulatethefunction
ofthe antilock system,arecontained in adiecast aluminum
housing and are environmentally protected by silicone
encapsulation. Themetal housing, coupledwiththedesign
ofthedigitalelectronics,isintended toprovide ahighdegree
ofprotectionfrom radio andelectromagneticinterference.
A diagnostics display window with 9 light emitting diodes
(LEDs) and a magnetically actuated Reset switch is
incorporated in the housing for troubleshooting and
diagnosticpurposes.
Twoelectrical connectors arecurrentlyused on theEC-14™
controller, one for connection to the antilock system
components (30 pin, Packard Electric, 150 series "Metri-
pack”) and one for connection to a combination
modulator-relayvalve (4pin,Molex).
MOUNTING
TheEC-14™controllerisspecificallydesignedtobemounted
to a modulator-relay valve assembly, such as the Bendix®
M-12™modulator (reference SD-13-4772). When the
EC-14™controlleris mounted on amodulatorassemblythe
30 PIN WIRE
HARNESS CONNECTOR
DIAGNOSTICS
WINDOW
MOUNTING HOLES (4)

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FIGURE 2 - MC-14™ANTILOCK BRAKE SYSTEM

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M-12™
MODULATOR
ASSEMBLY
resulting assembly receives a different designation. For
example, when the EC-14™antilock controller is mounted
on the M-12™modulator the resulting assembly is known
asaMC-14™modulatorcontroller(seeFigure3).
EC-14™CONTROLLER INFORMATION
INPUTS AND COMMAND OUTPUTS
GENERAL
The EC-14™controller receives information from several
components in the antilock system and, based on these
inputs, issues commands or delivers information. Some
portions of the EC-14™controller both receive and deliver
commandsandinformation.
INPUTS
Wheel Speed Information is provided to the EC-14™
controllerviaawiringharnessfrom individualspeed sensors
located in the trailer wheels or axle housing. Working in
conjunction with an exciter or tone ring, the speed sensors
provideinformationtotheEC-14™controllerintheformofan
ACsignalwhichvariesinvoltageandfrequencyasthespeed
ofthewheelincreasesordecreases.
The EC-14™controller is designed to receive wheel speed
information, from various wheel speed sensor models, at
the rate of 100 pulses per wheel revolution. The EC-14™
controllerisable tosimultaneouslyreceive,and individually
interpret, speed signals from four wheel speed sensors (2
axles).
Vehicle Power is supplied to the EC-14™controller from
thefrom the ignitionswitchthrough a fuseorcircuit breaker.
Theelectrical groundforthe EC-14™controlleristhevehicle
chassis.
A Stop Light Switch connection to the EC-14™controller
isprovidedandserves to“signal”theEC-14™controllerof all
brakeapplications.Althoughthestoplightswitchconnection
enhancestheEC-14™antilockcontrollerperformance,aloss
of the stop light switch “signal” will not prevent antilock
operation.
OUTPUTS
Modulators, like the Bendix®M-12™and M-21™or M-22™,
are the means by which the EC-14™antilock controller is
able to modify driver applied air pressure to the service
brakes. The EC-14™controller is able to simultaneously
andindependentlycontrol two modulator assemblies.
FIGURE 3 - MC-14™MODULATOR CONTROLLER ASSEMBLY
EC-14™CONTROLLER
DIAGNOSTIC
WINDOW
MODULATOR
EXHAUST
WIRE HARNESS
CONNECTOR
SERVICE
PORT
SOLENOID
EXHAUST
SUPPLY (2)
DELIVERY PORTS (4)

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FIGURE 4 - WS-20™WHEEL SPEED SENSORS & CONNECTORS
PACKARD 2 PIN
CONNECTOR
DEUTSCH 2 PIN
CONNECTOR
90° WS-20™WHEEL
SPEED SENSOR
STRAIGHT WS-20™
WHEEL SPEED SENSOR
BRAKE DRUM
SPEED SENSOR
MOUNTING
BLOCK
100 TOOTH SPEED
SENSOR EXCITER
RING
WS-20™WHEEL
SPEED SENSOR
(90 DEG.)
HUB ASSEMBLY
FIGURE 4A - WS-20™WHEEL SPEED SENSOR INSTALLATION

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FIGURE 5 - M-21™& M-22™MODULATORS
The EC-14™controller is designed to be mounted directly
on a modulator relay valve assembly like the M-12™
modulator.Thetwoseparatecomponents(EC-14™controller
and M-12™modulator) become a single assembly. The
M-12™modulator is a combination valve consisting of a
standard relay valve and solenoid assembly. The M-12™
modulatorreplacesthestandard relay valve used to speed
up the application and release of the vehicle’s rear axle
brakes. An internal, four pin, wiring harness connects the
EC-14™controllertotheM-12™modulatorsolenoidassembly.
ForadditionalinformationandserviceproceduresseeBendix
ServiceData SheetSD-13-4772.
In addition to the M-12™modulator, the EC-14™controller
alsocontrolsasingle,externalmodulatorliketheM-21™or
M-22™. Connected to the EC-14™controller via a wire
harness, the M-21™or M-22™modulator is essentially a
high capacity, on/off air valve that incorporates a pair of
electrical solenoids for control. The solenoids provide the
electric-air link between the antilock controller electronics
and the air brake system. Unlike the M-12™, the M-21™or
M-22™modulatoris notcombinedwith aservicerelay valve.
ForadditionalinformationandserviceproceduresseeBendix
ServiceData SheetSD-13-4793.
A Dash Light and its electrical relay is connected to, and
controlledby,theEC-14™controllerandserves as ameans
ofadvising the driverofthe condition oftheantilock system.
Aconnection to the Engine or Transmission Retarder is
providedon the EC-14™controller whichallowstheEC-14™
controllerto temporarily“disable”theretarder duringcertain
modesofoperation. While theEC-14™controlleris capable
ofthisfunction,andconnectionsareprovided,itisnotalways
used. Use of the retarder disable function is not essential
buthighlyrecommendedforvehiclesequippedwitharetarder.
The Data Link function enables the EC-14™controller to
“report” its operating condition to a specialized, external
computerin response tocertaincommandsit receives.The
EC-14™controllerdata linkconfigurationconforms toS.A.E.
standardJ1708andtheprotocol,or coded language used,
conforms to S.A.E. standard J1537. There are two
connections to the EC-14™controller devoted to the data
link.WhiletheEC-14™controlleris capable of this function,
andconnectionsareprovided,it is not always used. Use of
thedatalinkisnotessentialfor the EC-14™controller to be
functional.
OPERATION
OPERATIONAL PHILOSOPHY
TheBendix®EC-14™controllerprovidesaxlebrakingcontrol
by using four speed sensors and two modulators. By
monitoring the rate of deceleration during braking, and
subsequently adjusting the brake application pressure to
eachaxle, theEC-14™controlleris abletoprovide improved
brakingwhilemaintainingvehicle stability.
3 PIN WIRE
HARNESS
CONNECTOR
MOUNTING
HOLE
EXHAUST
SUPPLY
PORT
MOUNTING
HOLE
3 PIN WIRE
HARNESS
CONNECTOR
DELIVERY
PORT
EXHAUST
SUPPLY
PORT
M-22™MODULATOR M-21™MODULATOR

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Rear Axle Brakes - The vehicle’s rear axle brakes are
controlled by the MC-14™modulator controller (EC-14™
controllerandM-12™modulator).Likethe standard service
relayvalveitreplaces,theM-12™modulatordelivers brake
application pressure to the service chambers on the rear
axle equally. Two speed sensors on the rear axle “report”
changes in acceleration and deceleration to the EC-14™
controller. If required, the EC-14™controller adjusts the
applicationpressureto the rear axle servicebrakes,viathe
M-12™modulator,basedonthewheelbehavior“reported”
toitbythe speed sensors. In thecaseofvehiclesequipped
with tandem rear axles (6x2, 6x4), the speed sensors are
installed on the axle that is most likely to lose traction first.
TheMC-14™modulator controllercontrolsallservicebrakes
onthe tandemequally.
TheEC-14™controller utilizesa “SelectSmart”brakecontrol
philosophy for the rear axle brakes. This means that the
EC-14™controllerwillinitiallyadjust application pressure to
allrearaxleservicechambersbasedonthespeedinformation
from the first wheel to approach a locked condition. The
initialpressure adjustment willattempttoprevent allwheels
ontheaxle(s)fromlocking.Ifasubstantialbrakingdifference
is detected between the two wheels on the axle equipped
withthespeedsensors,theEC-14™controller will override
the first air pressure adjustment and allow one wheel to
lock. Both wheels including the locked wheel will continue
to be monitored for speed and braking difference changes
thatwouldrequirepressure adjustments.
Steering Axle Brakes - The steering axle brakes are
controlledby theEC-14™controllerand theM-21™orM-22™
modulator.Althoughconnectedtothe EC-14™controllervia
a wire harness, the M-21™or M-22™modulator is not an
integralpartof the MC-14™modulator controller assembly.
Brake application air passes through the M-21™or M-22™
modulator on its way to the front axle service chambers
fromthe footvalve.
Two speed sensors on the front axle “report” changes in
accelerationanddecelerationtothe EC-14™controller.
The EC-14™controller uses a “Select Low” brake control
philosophyfor thefrontaxle brakes.Itwill attempttoprevent
wheel lock by adjusting application pressure to both front
axleservice chambersbasedonthespeed informationfrom
thefirst wheeltoapproach alockedcondition. TheM-21™or
M-22™modulator provides the EC-14™controller with the
means of adjusting front axle service application pressure
whenrequired.
NON-ANTILOCK BRAKE APPLICATION
During normal braking, the brake valve simultaneously
deliversair tothecontrolport oftheM-12™modulator onthe
rear axle(s) as well as to and through the M-21™or M-22™
modulatoron the frontaxle.The M-12™modulatorfunctions
thesameasstandardservicerelayvalveandapplies air to
therearaxleservicebrakes.Becausethe M-21™or M-22™
modulator does not have a relay valve function, service air
passesthroughitto a quick release valveandfromthereto
thefrontaxleservicechambers.The servicebrakes arethus
applied.
Ifthespeed sensors donotdetectan impending wheellock
up, the EC-14™controller does not initiate any corrective
actionandthevehiclecomestoastopinanormalfashion.
ANTILOCK CONTROLLED BRAKE
APPLICATION - SYSTEM FULLY OPERATIONAL
Ifaservicebrakeapplicationis madeand thespeedsensors
detect an impending wheel lockup on an axle, the EC-14™
controller will immediately begin modification of the brake
application using the antilock modulator(s) at the affected
axle(s).
Solenoid valves contained in the modulator are energized
anddeenergizedbytheEC-14™controllerinordertomodify
thebrakeapplication.Whenasolenoidcoilis energized its
shuttlemoves,anddependinguponthefunctionofthespecific
solenoid, it either opens or closes, thereby causing the
exhaustorre-applicationofairpressuretothebrakechamber.
The solenoids in either the M-12™or M-21™modulator are
controlled independently by the EC-14™controller. By
opening and closing the solenoid valves in the appropriate
modulator,theEC-14™controller is actuallysimulatingwhat
thedriverdoeswhen he “pumps the brakes”.
It must be remembered however that unlike the driver, the
EC-14™controller is able to “pump” brakes on either the
frontorrearaxle(s),orboth,independentlyandwithfargreater
speedandaccuracy.
ANTILOCK SYSTEM OPERATION -
COMPONENT FAULT STRATEGY
The Bendix®EC-14™controller handles equipment faults
usingaconservativefail-safephilosophy.Anysingleelectrical
problem with a component devoted to antilock braking,
resultsinsimultaneous illuminationoftheantilock condition
lampon thedashand atroubleshootingLED ontheEC-14™
controller. Depending upon the type of problem and its
position of occurrence the EC-14™controller can continue
antilockfunctionat a lower performance level, disableallof
the antilock on the vehicle or only a portion. When antilock
is disabled, the brakes on the affected axle(s) revert to
standardairbraking.
Complete antilock system shut down will occur if:
•Electrical power is below or above the 10 to 17 volt
operatingrange.
•A controller fault is detected.
•Twoormorefaults,regardless of where, are detected.

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•AnM-12™modulator malfunction on the rear axle(s).
•Onlyfrontaxle antilock willbedisabledif a problemwith
the M-21™or M-22™modulator is detected.
Aprobleminasinglespeedsensorwillnotresultindisabling
of the antilock system. If a speed sensor malfunction is
detected by the EC-14™controller, the remaining speed
sensorontheaxlewillbeusedtocontinueantilockoperation
ontheaxlebutataslightlydegradedlevelofperformance.
Withthe failed componentapproachdescribed, theantilock
system will attempt to provide the vehicle with the best
possible braking and stability even after a problem has
occurred. It should be remembered that the driver will be
advisedofanydegradedantilockoperationviathedashlamp
and that standard air braking will still be available on those
brakeswheretheantilockhasbeendisabled.
ANTILOCK WIRING
GENERAL NOTES
The wires that carry information and power into and out of
the EC-14™controller are grouped and terminate at a
connectorwhichplugsinto theEC-14™controller.Thewiring
harnessesandconnectors are weather proofandthewires
that enter the connector are sealed to the connector. The
wire gauge used in the wire harnesses is specific to the
taskperformed.
Whendiagnosing wiring intheantilock system thefollowing
generalrulesapplyandshouldbefollowedwhereapplicable:
1. Itis generally advisabletoreplacea wire harnessrather
than repair individual wires in the harness. If a splice
repair must be made, it is important that the splice be
properlysolderedwitharosinflux(notacidbased)and
thesplicemadewaterproof.
2. Donotpiercewireinsulationwhencheckingforcontinuity.
Checkforpower,groundorcontinuity by disconnecting
theconnectorandtestingtheindividualpinsor sockets
intheconnector(s).
3. Always check the vehicle handbook for wire and
connectoridentification. Individual wireidentificationwill
differdependingupon thetypeofconnectors in use,the
vehiclemanufacturer,andthesystemfeaturesinuse.
4. Whiletheretarder disable andseriallinkconnections (3
total)arepresentonallEC-14™controllerstheyarenot
alwaysused.
PREVENTATIVE MAINTENANCE
GENERAL
Important: Review the warranty policy before performing
anyintrusivemaintenanceprocedures.Anextendedwarranty
maybevoided if intrusivemaintenanceisperformed during
thisperiod.
Becauseno twovehicles operateunderidenticalconditions,
maintenanceandmaintenanceintervalswillvary.Experience
is a valuable guide in determining the best maintenance
intervalforany oneparticularoperation.
Visuallycheck for physicaldamagesuchas brokenairlines
and broken or missing parts.
Perform the tests and inspections presented at the
prescribedintervals. IftheEC-14™controller failstofunction
asdescribed,itshouldberepairedorreplacedwithagenuine
Bendixunit, available at any authorized partsoutlet.
Every3 monthsor 25,000 miles,or 900operating hours:
1. Check all wiring and connectors to ensure they are
secureandfree fromvisibledamage.
2. AlthoughtheEC-14™controllerincorporatesaselfcheck
diagnostics, the LED display should be inspected to
ensurethatthey are functional. With the tractor ignition
onandabrakeapplicationheldapplied,holdamagnet
(800 gauss; capable of picking up 3 ounces) on the
Diagnostic Window Reset Switch and note all of the
LEDs illuminate. If one or more of the LEDs do not
illuminate andtheantilock condition lamp onthetrailer
indicates the system is functioning properly, the non-
illuminatedLED(s) should benotedfor future reference.
Although the diagnostic capabilities will be limited, the
system will continue to function as designed.
3. Road test the trailer by making an antilock stop from a
vehicle speed of 20 miles per hour. When an antilock
stop is made, the modulator solenoids pulsate and an
audible burst of air can be heard. The wheels should
not enter a prolonged "lock" condition.
WARNING! PLEASE READ AND FOLLOW
THESE INSTRUCTIONS TO AVOID
PERSONAL INJURYOR DEATH:
When working on or around a vehicle, the following
general precautions should be observed at all times.
1. Park the vehicle on a level surface, apply the
parking brakes, and always block the wheels.
Always wear safety glasses.
2. Stop the engine and remove ignition key when
working under or around the vehicle. When
working in the engine compartment, the engine
should be shut off and the ignition key should be
removed. Where circumstances require that the
enginebe in operation,EXTREME CAUTIONshould
be used to prevent personal injury resulting from
contact with moving, rotating, leaking, heated or
electrically charged components.
3. Do not attempt to install, remove, disassemble or
assemble a component until you have read and
thoroughly understand the recommended
procedures. Useonly the propertools and observe
all precautions pertaining to use of those tools.

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FIGURE 6 - MC-14™ANTILOCK WIRING SCHEMATIC

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4. If the work is being performed on the vehicle’s air
brake system, or any auxiliary pressurized air
systems,make certainto drainthe air pressurefrom
all reservoirs before beginning ANY work on the
vehicle. If the vehicle is equipped with an AD-IS™
air dryer system or a dryer reservoir module, be
sure to drain the purge reservoir.
5. Following the vehicle manufacturer’s
recommendedprocedures, deactivatethe electrical
system in a manner that safely removes all
electrical power from the vehicle.
6. Never exceed manufacturer’s recommended
pressures.
7. Never connect or disconnect a hose or line
containing pressure; it may whip. Never remove a
component or plug unless you are certain all
system pressure has been depleted.
8. Use only genuine Bendix®replacement parts,
components and kits. 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.
9. Components with stripped threads or damaged
parts should be replaced rather than repaired. Do
not attempt repairs requiring machining or welding
unless specifically stated and approved by the
vehicle and component manufacturer.
10. Prior to returning the vehicle to service, make
certain all components and systems are restored
to their proper operating condition.
REMOVING EC-14™CONTROLLER ASSEMBLY
LocatetheEC-14™controlleronthetrailer and determine if
it is mounted on a modulator (e.g. M-12™modulator) or is
remotemountedto atrailerframemember using abracket.
Use the appropriate removal procedurebelow.
Removing the EC-14™Controller and M-12™Modulator:
1. Identify and remove all air lines connected to the
M-12™modulator.
2. Disconnect the electrical connector from the EC-14™
controller.
3. Note and mark the mounting position of the MC-14™
modulator-controllerassembly on the vehicle. Loosen,
remove and save the nuts on the mounting hardware
that attaches the MC-14™modulator controller bracket
tothe vehicle.RemovetheMC-14™modulatorcontroller
assemblyfromthevehicle.
4. Remove as much contamination as possible from the
exterior of the assembly making sure to keep the
contaminationawayfromtheopenports.
5. Note and mark the position of the EC-14™controller
relativetothe M-12™modulator. Remove andretainthe
four hex cap screws that secure the EC-14™controller
totheM-12™modulator. Carefully separatethe EC-14™
controllerfromtheM-12™modulatorenoughtoexpose
the wire harness that connects both units electrically.
Disconnect the wire harness by separating the four pin
connectorat theEC-14™controller.Peelthegasketfrom
theEC-14™controller or M-12™modulatorandretain for
reuse. Note: Use a new gasket if damaged during
removalorifanewgasketisimmediatelyavailable.
INSTALLING THE EC-14™CONTROLLER
ASSEMBLY
1. After noting the positioning marks made prior to
disassembly, reconnect the M-12™modulator wire
harness to the EC-14™controller, position the gasket
on the EC-14™controller then secure the EC-14™
controller to the M-12™modulator using the four cap
screws. Torque the cap screws to 50-80 Ibs. in.
2. Mount the assembled MC-14™modulator controller on
the vehicle and orient it in the position marked prior to
removal.
3. Reconnect all air lines.
4. Reconnect the electrical connector to the EC-14™
controller.
5. Test the MC-14™modulator controller for operationand
airleakagepriortoplacingthevehicleinservice.
6. Perform the “Initial Start up Procedure” in the
Troubleshooting section to assure proper antilock
systemoperation.
DIAGNOSINGAND LOCATINGASYSTEM
PROBLEM
GENERAL
The EC-14™controller contains self test and diagnostic
circuitry that continuously checks for proper operation of
FIGURE 7 - MC-14™MODULATOR CONTROLLER
EC-14™
CONTROLLER
GASKET
MOUNTING
BRACKET
M-12™
MODULATOR

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theentire antilock systemincludingwiring continuity.Adash
lamp,controlled bytheEC-14™controller, advisesthedriver
oftheconditionofthe entire antilock system. The condition
ofspecific antilock componentsisprovided to themechanic
byaseriesoflabeled,lightemittingdiodes(LED’s) displayed
through a “window” in the EC-14™controller housing. No
special tools or equipment are needed to read or interpret
theEC-14™controllerdiagnosticswindow.It shouldbenoted
that the diagnostics display is separate from the antilock
conditionlamponthedash. With this separation, the driver
is aware of any problems that occur, but is not concerned
within-depthdiagnostic information.
Aspecial featureoftheEC-14™controllerdiagnostic system
is its failure latching. Intermittent problems, particularly in
the wheel speed sensing area can be difficult to diagnose.
Whenthecontrollersensesanerroneouscondition,whether
inthe controllerelectronics,the modulatororspeed sensing
areas,itstorestheconditioninnon-volatilememory,disables
the antilock function if necessary, illuminates the dash
mounted antilock condition lamp and the appropriate
diagnosticLEDson the EC-14™controller.The malfunction
condition is truly stored and is not cleared by loss of power
totheEC-14™controller.TheLEDswillre-lightwhen power
is restored and remain illuminated until the problem is
corrected.Aftertheactualproblemiscorrected,maintenance
personnel can clear or reset the EC-14™controller
diagnostics by passing a small magnet over the RESET
pointin the diagnostics window.
DIAGNOSTIC LEDS
There are nine LEDs plus a magnetically actuated reset
switchinthe EC-14™controller diagnostic window.Thefirst
five LEDs locate a problem to a specific area of the trailer
while the last four indicate the problem component or its
wiring.The LEDsarecomputercontrolledand areeitherON
orOFF depending upontheirmonitor function. (Note: Right
andleft, frontandreararedeterminedfromthedriver's seat.
Leftfront is therefore the corner closest to the driver.)
LED o FRONT RedLED
LED o MID Red LED (SEE NOTE)
LED o REAR RedLED
LED o RIGHT RedLED
LED oLEFT RedLED
LED o MOD RedLED
LED o SENS RedLED
LED o ECU RedLED
LED oVOLT GreenLED
¦ ¦ ¦ RESET No LED
Note: TheMIDLED shown in thechartaboveisnot used
inthediagnosticprocessfortheEC-14™controller
however,itwill lightwhena magnetisplacedonthe
RESET switch in the diagnostic window.
"FRONT" LED
ThisRed LEDilluminatesand latcheson inorder toindicate
thelocationof a problemcomponentorits wiring. It willlight
in conjunction with either the RIGHT or LEFT LED and the
SENS LED when indicating a speed sensor problem. The
FRONTLED willalsolightin conjunctionwiththe MODLED
to indicate that the front modulator (M-21™or M-22™) or its
wiringhasmalfunctioned.
"MID" LED
This red LED is not used in troubleshooting the EC-14™
controller and should light only when a magnet is held on
the RESET switch.
"REAR" LED
ThisredLED illuminates and latches on inordertoindicate
thelocationof a problemcomponentorits wiring. It willlight
in conjunction with either the RIGHT or LEFT LED and the
SENS LED when indicating a speed sensor problem. The
REAR LED will also light in conjunction with the MOD LED
toindicatethattherearmodulator(M-12™)oritswiringhas
malfunctioned.
FIGURE 8 - EC-14™CONTROLLER DIAGNOSTIC WINDOW

11
"RIGHT" LED
ThisredLED illuminates and latches on inordertoindicate
the location of a problem component or its wiring. It will
light in conjunction with either the FRONT or REAR LED
and SENS LED. This LED should not light when a MOD
LED is on.
"LEFT" LED
ThisredLED illuminates and latches on inordertoindicate
the location of a problem component or its wiring. It will
light in conjunction with either the FRONT or REAR LED
and SENS LED. This LED should not light when a MOD
LED is on.
"MOD" LED
This red LED illuminates and latches on to indicate a
permanent or intermittent open or short circuit in the
solenoids of one of the two modulators or the wiring
connectingthemtothesystem. TheMODLEDwillilluminate
inconjunctionwitheither the FRONT or REAR LED.
"SENS" LED
This red LED illuminates and latches on to indicate
permanentor intermittentproblem. Thefaultsindicatedare;
openor shortedwheelspeedsensor,openor shortedwheel
speedsensorwiring,wheelspeedsignalnotpresentordoes
notconformtodesign criteria. TheSENS LEDwillilluminate
in conjunction with either the FRONT or REAR and either
theRIGHTor LEFT LED.
"ECU" LED
Thisred LED, whenilluminated,indicates thatthecontroller
itself has failed. It is latched on for all EC-14™controller
faults except low voltage. For voltages less than 9 vdc, the
LED illuminates to indicate the controller is inoperative,
howeverwhen thevoltageagain exceeds9vdc theLEDwill
go out by itself.
"VOLT" LED
This green LED illuminates and remains on during vehicle
operation to indicate that vehicle power is reaching the
controller.Ifvehiclepowerisoutofrangeforproperoperation
(below10vdcorabove17vdc)thisLEDwillflashuntilpower
is brought into range. This LED may also flash indicating
thata“marginal” low voltageconditionexistedat the timeof
anantilockevent.
"RESET"
Beneath the RESET area of the window display is a
magnetically sensitive switch that is used to reset the
diagnostic system. The device will respond to a magnet
whichhasstrength sufficient to liftathree(3) ounce weight.
Holdingamagnet againsttheRESETwill cause allLEDsto
light during the time the magnet is against it.
TROUBLESHOOTING
GENERAL
While the EC-14™controller diagnostic display locates a
specificproblem area,itis stillnecessarytoconfirmwhether
the problem resides in the component itself or the wiring.
Basically the troubleshooting procedure that follows is
devoted to narrowing the problem to either the wiring or a
specific antilock component. It should be noted that all
troubleshootingbegins byobservingthe antilockstatus
lamp on the dash while performing the "Initial Start-
up Procedure" and following the directions contained in
theprocedure.
IMPORTANT - TROUBLESHOOTING TIPS
1. Record all findings and the action taken during the
troubleshooting process. The record sheet should be
filedin thetrailermaintenance folderforfuture reference
andcomparison.
2. No voltage or resistance tests are performed into
the EC-14™controller. All voltageand resistancetests
are performed by beginning at the wire harness half of
the connector and moving away from the EC-14™
controller toward an antilock system component
(modulator,wheelspeedsensor,etc.).

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TROUBLESHOOTING
INITIAL START-UP PROCEDURE
Dash lamp does not blink, comes on
and remains illuminated?
Is dash lamp illuminated?
Turn ignition ON and observe dash
antilock condition lamp.
Note: If brakes are applied when
ignition is turned on, a short
exhaust of air will be heard at front
and rear modulators.
Go to Section I
“Dash Lamp Testing”
YES
YES
NO
Dash lamp remains on?
NO
Go to Section III
“Inspection for
illuminated LEDs”
YES
NO
The system is functioning normally.
Make notes of the parts replaced or repaired
and steps taken.
AMBERSTATUSLAMP
BLINKSONCE,
THENGOESOUT:
SYSTEM- OK
AMBERDASHLAMPOFF:
SYSTEM- OK
Dash lamp comes on, flashes and stays on.
Increase vehicle speed to above 10 mph for at
least 30 seconds and observe the dash lamp.
Go to Section II
“Inspection for Illuminated
LEDs”
STARTHERE

13
Is voltage correct?
Is dash lamp illuminated?
Disconnect 30 pin wire harness
connector from EC-14™controller
and observe the dash lamp.
NO
YES
NO
YES
Repeat the “Initial Start-up
Procedure”
EC-14™Controller
Wire Harness
Connector
1A&2A
GROUND
With ignition on, measure voltage between
lamp relay (Pin 3F) and ground (Pins 1A, 2A).
Voltage should be same as battery voltage.
Replace the EC-14™
controller
Go to Section II
“Inspection for Illuminated
LEDs”
Check wiring harness and relay for shorts to
ground. Reconnect and check/replace the
following:
1. Dash light bulb.
2. Relay power wire.
3. Relay.
After replacing each component test
the dash lamp.
TROUBLESHOOTING
SECTION I
DASH LAMP TESTING
3F
DASHLAMP
RELAY
STARTHERE

14
Check closely: is green
LED illuminated?
Inspect EC-14™controller and record
presence of illuminated LEDs
Is green LED Flashing?
YES
YES(ON)
Are any red LED’s
illuminated?
YES
NO
NO(OFF)
Are any red LED’s
illuminated?
Go to Section IV
“Inspection for
Illuminated LEDs”
NO
Record the condition of
all red LEDs
Go to Section IX
“Testing for False Failure
Indication - Caused by Dash
Lamp Relay”
NO
Go to Section V
“Testing for Power
to the EC-14™
controller”
CHECK
“VOLT”LED
YES
Go to Section V
“Testing for Power
to the EC-14™
controller”
TROUBLESHOOTING
SECTION II
INSPECTION FOR ILLUMINATED LEDs
Replace EC-14™controller.
Repeat the “Initial Start-up
Procedure.”
ON?
FLASHING?
STARTHERE

15
Check closely: Is green
LED Illuminated?
Inspect EC-14™controller and record
presence of illuminated LEDs
Is green LED flashing?
YES Are any red LEDs
illuminated?
YES
NO
NO(OFF)
Go to Section V
“Testing for Power
to the EC-14™
controller”
Are any red LEDs
illuminated?
Go to Section IV
“Inspection for
Illuminated LEDs”
Record the condition of
all red LEDs
Go to Section X
“Testing For False Failure
Indication - Caused by Wheel
Speed Components”
NO
Go to Section V
“Testing for Power
to the EC-14™
controller”
CHECK
“VOLT”LED
Check
red LEDs
TROUBLESHOOTING
SECTION III
INSPECTION FOR ILLUMINATED LEDs
Replace EC-14™controller.
Repeat the “Initial Start-up
Procedure.”
ON?
FLASHING?
YES(ON)
ARE
ANY
ILLUMINATED?
YESNO
STARTHERE

16
Go to Section V
“Testing for Power
to the EC-14™
controller”
If any other red LEDs are
illuminated, replace the EC-14™
controller and repeat the “Initial
Start-up Procedure”
Is red “MOD” LED
illuminated?
Is this LED illuminated?
NO(OFF)
Is red “SENS” LED
illuminated? YES
Note red “ECU” LED in
EC-14™controller
diagnostics window
Is the red “RIGHT” or
“LEFT” LED illuminated?
See Note 1 below
Is the red “RIGHT” or
“LEFT” LED illuminated?
SEE NOTE 1
SEE NOTE 1
TESTING
“MOD”LED
SEE NOTE 1
SEE NOTE 1
TESTING
“SENS”LED
CHECK
“ECU”LED
NO
Is the red “FRONT” or
“REAR” LED illuminated?
See Note 1 below
Is the red “FRONT” or
“REAR” LED illuminated?
See Note 1 below
NO
YES
“REAR” LED
“FRONT” LED
Go to Section VII
“Testing the Rear
Modulator”
ON? ON?
ON?
YES
TROUBLESHOOTING
SECTION IV
INSPECTION FOR ILLUMINATED LEDs
NO
NO
YES(ON)
YES
YES
Go to Section VI
“Testing the Front
Modulator”
Replace EC-14™
controller.
Repeat the “Initial
Start-up Procedure.”
Replace EC-14™
controller.
Repeat the “Initial
Start-up Procedure.”
NO
Replace the EC-14™
controller and repeat the
“Initial Start-up
Procedure”
NO
YES
Note the three
illuminated LEDs and
go to Section VIII
“Testing the Wheel
Speed Sensor”
1. Ifboth oftheseLEDsareilluminated,replacetheEC-14™controller.
NOTE
STARTHERE

17
Is voltage same as battery
voltage? Must be between
11 and 17 volts.
Turn ignition off, disconnect wire
harness connector from EC-14™
controller
YES
1A&2A
GROUND
TROUBLESHOOTING
SECTION V
TESTING FOR POWER TO THE EC-14™CONTROLLER
EC-14™Controller Wire
Harness Connector
1K, 2K
POWER
YES
Turn ignition off, reconnect wire harness to
EC-14™controller, turn ignition on
Turn ignition on and measure voltage between
power and ground pins on wire harness
connector:
1Ato1K.
1Ato2K.
2Ato 1 K.
2Ato 2 K.
Reconnect connector to EC-14™
controller. Check the vehicle wiring
for continuity. Refer to the vehicle
service manual and check the
battery voltage. Repair or replace
as necessary and repeat the “Initial
Start-up Procedure.”
NO
Perform a magnetic reset by passing a magnet
over the “RESET” in EC-14™controller
diagnostic window then remove magnet
Replace the EC-14™
controller. Repeat the
“Initial Start-up Procedure.”
Is green “VOLT” LED still flashing or red
“ECU” LED still on?
NO Repeat the “Initial Start-up
Procedure.”
STARTHERE

18
TROUBLESHOOTING
SECTION VI A
TESTING FOR THE FRONT MODULATOR
EC-14™Controller Wire
Harness Connector
Probe connector with volt/ohm meter and not that proper
resistance values are obtained for modulator being tested.
Resistance values here for Bendix®M-21™modulator.
Hold to Source (2G to 1G): .................... Read 3.5 to 5 Ohms
Exhaust to Source (2F to 1G): ............... Read 3.5 to 5 Ohms
Exhaust to Hold (2F to 2G): ................... Read 7 to 10 Ohms
Source to Power (1G to 1K, 2K): ...........No Continuity
Source to Ground (1G to 1A, 2A): .......... No Continuity
Hold to Power (2G to 1K, 2K): ............... No Continuity
Hold to Ground (2G to 1A, 2A): .............. No Continuity
Exhaust to Power (2F to 1K, 2K):...........No Continuity
Exhaust to Ground (2F to 1A, 2A): ......... No Continuity
NO
Go to Section VI Band
continue testing
Are resistance values correct?
1A&2A
GROUND
2F
EXHAUST
2G
HOLD
1K, 2K
POWER
1G
SOURCE
Inspect connector and reconnect to EC-14™
controller. Turn ignition on and pass magnet
over “RESET” on EC-14™controller. Remove
magnet and note reaction of red LEDs
Are any red LEDs
illuminated?
Repeat the “Initial Start-up
Procedure.” If testing has
returned to this step
twice, replace the EC-14™
controller and retest.
YES
NO
Are same red LEDs
illuminated?
Replace EC-14™controller.
Repeat the “Initial Start-up
Procedure”
YES
NO
Go to Section IV
“Inspection for Illuminated
Red LEDs” and retest
YES
Turn ignition off, disconnect wire
harness connector from EC-14™
controller.
START HERE

19
TROUBLESHOOTING
SECTION VI B
TESTING FOR THE FRONT MODULATOR
START HERE
from Section VI A
Go to modulator, inspect wiring connector. Disconnect
connector and test resistance between pins on modulator.
Resistance values here for Bendix®M-21™modulator.
Hold to Source (C to B):......................... Read 3.5 to 5 Ohms
Exhaust to Source (A to B): .................... Read 3.5 to 5 Ohms
Exhaust to Hold (A to C):........................ Read 7 to 10 Ohms
Test each pin to vehicle ground and note no continuity
Are resistance values correct? Replace the front (M-21™)
modulator
NO
Reconnect connector to modulator. Turn ignition
on and pass magnet over “RESET” on EC-14™
controller and remove. Note reaction of red LEDs
Are any red LEDs
illuminated? Repeat the “Initial Start-up
Procedure”
Are same red LEDs
illuminated? YES
NO
Go to Section IV
“Inspection for Illuminated
red LEDs” and retest
YES
Repair or replace
modulator wire harness
C
HOLD
A
EXHAUST
B
SOURCE
NO
RESETTING
EC-14™CONTROLLER
MAGNET
HERE
YES
Connector on M-21™
FrontModulator

20
TROUBLESHOOTING
SECTION VII
TESTING FOR THE REAR (M-12™) MODULATOR
Is resistance in range? Replace the M-12™modulator
solenoid assembly
NO
Are any red LEDs
illuminated? Repeat the “Initial
Start-up Procedure”
Are same red LEDs
illuminated? YES
NO
Go to Section IV
“Inspection for Illuminated
Red LEDs”
YES
NO
RESETTING
EC-14™CONTROLLER
MAGNET
HERE
YES
STARTHERE
Turn the ignition off. Separate the EC-14™controller
from the M-12™modulator. Disconnect the four pin
connector between the two components and test
resistance on the modulator connector.
Black to black:........................................ 9 to 12 Ohms
White to white: ....................................... 9 to 12 Ohms
Reconnect EC-14™controller to M-12™
modulator. Turn ignition on and pass magnet
over “RESET” on EC-14™controller and
remove. Note reaction of red LEDs
Replace EC-14™controller.
Repeat the “Initial Start-up
Procedure.”
WHITE
WHITE BLACK
BLACK
M-12™MODULATOR
WIREHARNESS
CONNECTOR