Vanguard 25E300 Operating instructions

Vanguard®EFI Diagnostics
and Repair
25E300
REPAIR MANUAL
Not for
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Foreword
This manual was written to assist engine technicians and service personnel with the troubleshooting and repair procedures for
Briggs & Stratton® and Vanguard® engines equipped with Electronic Fuel Injection (EFI). It assumes that persons using this
manual have been properly trained and are familiar with the service procedures for these products, including the proper use
of required tools and the application of appropriate safety practices. Persons untrained or unfamiliar with these procedures or
products should not attempt to perform such work.
Proper repair is important to safe, reliable operation of all engines and engine-driven systems. The troubleshooting and
repair procedures described in this manual are appropriate for the Briggs & Stratton and Vanguard engines described herein.
Alternative methods or procedures may pose risks to both personal safety and engine reliability and are not endorsed or
recommended by Briggs & Stratton.
All information, illustrations, and specifications contained in this manual were based on the data available at the time of
publication. Briggs & Stratton reserves the right to change, alter, or otherwise improve the product or the product manuals at
any time without prior notice.
Briggs & Stratton offers two complementary publications to enhance understanding of engine technology, maintenance, and
repair. However, neither publication is a substitute for a recognized training program for engine technicians.
• For consumers, Small Engine and Equipment Maintenance Guide (Part No. CE8155) provides a comprehensive
overview of how small air-cooled engines work, basic troubleshooting, and step-by-step maintenance procedures.
• For engine technicians and consumers alike, an in-depth study of engine theory and operation can be found in the
textbook Small Engines (Part No. CE8020).
Both publications can be purchased at www.briggsandstratton.com or through a local Briggs & Stratton Authorized Service
Dealer.
© 2023 Briggs & Stratton. All rights reserved.
No part of this manual may be reproduced or transmitted in any form or by any means, electronic or mechanical, including
photocopying or recording by any information storage and retrieval system, without prior written permission from Briggs &
Stratton.
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Engine Models Covered
This engine repair manual includes the following engine models:
• MODEL 25E300
NOTE: Some models have limited service parts. Review the Illustrated Parts List for part availability before
conducting any service work.
NOTE: Many of the images in this document are representative of the Standard Chore engine. While other engines
models may appear somewhat different,unless indicated otherwise, the procedures are the same.
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How To Use This Manual
This manual is designed to assist in the diagnostic and troubleshooting process.Troubleshooting of anysystem follows a
similar methodology, in general there are seven steps in the troubleshooting process:
1. Identify the problem.Observe the issue or the symptoms of the issue. Identify the system in which the problem occurs.
2. Create a theory of the probable cause of the problem.Sometimes a problem may have multiple probable causes, in this
case, it is necessary to create a plan to test all possibilities to determine the root cause of the problem.
3. Test the theory.Testing individual components as well as systems can provide valuable data that leads to the root cause
of the problem.
4. Establish a plan to fix the problem.This may involve a repair, a replacement, or a combination.
5. Execute the plan.This includes repairs or replacements of components as well as any complementary repairs.
6. Verify that the problem is resolved.Sometimes, repairing the first issue will introduce a new issue, so it is important to test
the system for full functionality.
7. Document the process.Make sure to record all observations, test data, and repairs.
The manner in which the instructions are used depends upon the task to be performed and the level of disassembly and
servicing required.
Safety and General Information
Before starting any troubleshooting process, make sure you are familiar with ALL safety warnings and guidelines in SECTION
1 - SAFETY AND GENERAL INFORMATION.The preliminary instructions are designed to prepare you for the diagnostic and
repair steps.
Diagnostic Introduction
When diagnosing a specific problem with an engine or engine component, first see SECTION 2 - DIAGNOSTIC
INTRODUCTION. This section is designed to provide general knowledge of the engine's systems, preliminary diagnostic
steps, and the correct way to connect to the engine to retrieve and read diagnostic trouble codes (DTCs).
Troubleshooting Diagnostic Trouble Codes (DTCs)
When diagnosing DTCs, see SECTION 3 - TROUBLESHOOTING DTCs. This section of the manual provides information on
component locations,DTC definitions, diagnostic steps for each DTC, and action items to help with repairs.
Wire Harness Schematics and Pin-Outs
See SECTION 4 - WIRE HARNESS SCHEMATICS AND PIN-OUTS for information related to wire location, connector pin
location, wiring schematics, pin-out diagrams and additional information related to testing engine component wiring.
Symptoms and Troubleshooting
This section is designed to be used as a guide for diagnostics on the engine. This section provides potential problem
scenarios, potential causes for those problems, and action items to help with the repair.
Removal and Installation
Depending on the service being performed, SECTION 6 - REMOVAL AND INSTALLATION provides the procedures to
correctly remove and replace a component. The order in which the topics are presented is the order in which assemblies are
most easily removed from the engine.
Specifications
This section provides a list of relevant engine specifications for reference. This includes torque specifications, engine
parameter specifications and any other specification that is necessary to reference during diagnostic troubleshooting and
replacement.
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SECTION 1 - SAFETY AND GENERAL INFORMATION 1
SECTION 2 - DIAGNOSTIC INTRODUCTION 2
SECTION 3 - TROUBLESHOOTING DTCs 3
SECTION 4 - WIRE HARNESS SCHEMATICS AND PIN-OUTS 4
SECTION 5 - SYMPTOMS AND TROUBLESHOOTING GUIDE 5
SECTION 6 - REMOVAL AND INSTALLATION 6
SECTION 7 - SPECIFICATIONS 7
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1
SECTION 1 - SAFETY AND GENERAL INFORMATION
GENERAL SAFETY MESSAGES ------------------------------------------------------------------------------------------------------------------------8
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General Safety Messages
Prior to work, read and understand the section(s) of this
manual that pertain to the job. Follow all safety warnings.
• Always use fresh gasoline. Stale fuel can cause gum
deposits in the carburetor and cause leakage, flow
restrictions, or other problems.
• Check fuel lines and fittings frequently for cracks or
leaks and replace if necessary.
WARNING
Failure to read and obey the operator’s manual, all warnings,
and operating instructions could result in death or serious
injury.
WARNING
Briggs & Stratton® Engines are not designed for
and are not to be used to power: fun-karts; go-karts;
children's, recreational, or sport all-terrain vehicles (ATVs);
motorbikes; hovercraft; aircraft products; or vehicles used
in competitive events not sanctioned by Briggs & Stratton.
For information about competitive racing products, see
www.briggsracing.com. For use with utility and side-by-side
ATVs, please contact Briggs & Stratton Power Application
Center, 1-866-927-3349. Incorrect engine use could result in
serious injury or death.
WARNING
Fuel and its vapors are flammable and explosive. Fire or
explosion could result in burns or death.
When you add fuel
• Stop the engine. Before you remove the fuel cap, wait
a minimum of two (2) minutes to make sure that the
engine is cool.
• Fill the fuel tank outdoors or in an area that has good
airflow.
• Do not put too much fuel in the tank. For expansion
of the fuel, do not fill above the bottom of the fuel tank
neck.
• Keep fuel away from sparks, open flames, pilot lights,
heat, and other ignition sources.
• Frequently examine the fuel lines, fuel tank, fuel cap,
and connections for cracks or leaks. Replace damaged
parts.
• If fuel spills, wait until it dries before you start the
engine.
When you start the engine
• Make sure that the spark plug, muffler, fuel cap and air
cleaner (if equipped) are correctly installed.
• Do not crank the engine with the spark plug removed.
• If the engine is flooded, set the choke (if equipped)
to the OPEN or RUN position. Move the throttle (if
equipped) to the FAST position and crank until the
engine starts.
• If there is natural or LP gas leakage in the area, do not
start the engine.
• Because vapors are flammable, do not use pressurized
starter fluids.
When you operate the equipment
• Do not tilt the engine or the equipment at an angle which
causes fuel to spill.
• Do not choke the carburetor (if equipped) to stop the
engine.
• Do not start or operate the engine with the air cleaner (if
equipped) or the air filter (if equipped) removed.
When you do maintenance
• If you drain the oil from the top oil fill tube, the fuel
tank must be empty. If it is not empty, fuel leakage can
occurand could result a fire or an explosion.
• During maintenance if it is necessary to tilt the unit,
make sure that the fuel tank, if mounted on the engine,
is empty and that the spark plug side is up. If the fuel
tank is not empty, leakage can occurand could result a
fire or an explosion.
• Frequently examine the fuel lines, fuel tank, fuel cap,
and connections for cracks or leaks. Replace damaged
parts.
• Do not change the governor spring, links or other parts
to increase engine speed.
• Do not hit the flywheel with a hammer or hard object.
This could result in failure of the flywheel during
operation.
• Replacement parts must be of the same design and
installed in the same position as the original parts. Other
parts could result in damage or an injury.
When you move the location of equipment
• Make sure that the fuel tank is EMPTY or that the fuel
shut-off valve is in the CLOSED position.
When fuel or equipment is in storage with fuel in the fuel
tank
• Because pilot lights or other ignition sources can cause
explosions, keep fuel or equipment away from furnaces,
stoves, water heaters or other appliances that have pilot
lights.
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WARNING
Fuel vapors are flammable and explosive. Fire or
explosion could result in burns or death. Always observe
the following safety precautions before removing any
fuel system components:
• Wear eye protection.
• Relieve fuel system pressure.
• Make surethere are no open flames or potential ignition
sources in the area.
• When removing a fuel hose or fitting, cover with a shop
towel to catch and fuel leakage.
• Collect any fuel and/or shop towels in approved
containers and dispose of properly.
• Make sure to keep dirt and debris out of fuel lines,
injectors and fuel pumps.
• Keep a dry chemical fire extinguisher on hand in case of
emergencies.
WARNING
Fuel vapors are flammable and explosive. Fire or
explosion could result in burns or death.
If you smell gas
• Do not start the engine.
• Do not switch on electrical switches.
• Do not use a phone in the vicinity.
• Evacuate the area.
• Contact the gas supplier or the fire department.
WARNING
Fuel vapors are flammable and explosive. Fire or
explosion could result in burns or death.
• Do notstart and operate the engine with the air cleaner
assembly (if equipped) or the air filter (if equipped)
removed.
WARNING
Fuel vapors are flammable and explosive. Fire or
explosion could result in burns or death.
Engine start-up causes spark that could result in a fire or
explosion.
• If there is natural or LP gas leakage in the area, do not
start the engine.
• Because vapors are flammable, do not use pressurized
starter fluids.
WARNING
POISONOUS GAS HAZARD. Engine exhaust contains
carbon monoxide, a poisonous gas that could kill you in
minutes. Although you do not smell exhaust fumes, you
could still be exposed to dangerous carbon monoxide
gas. If you feel sick, dizzy, or weak while you use this
product, get to fresh air RIGHT AWAY. See a doctor. You
may have carbon monoxide poisoning.
• Carbon monoxide gas can collect in occupied spaces.
To reduce the risk of carbon monoxide gas, ONLY
operate this product outdoors and far away from
windows, doors and vents.
• Install battery-operated carbon monoxide alarms or
plug-in carbon monoxide alarms with battery back-up
as specified by the manufacturer's instructions. Smoke
alarms cannot sense carbon monoxide gas.
• DO NOT operate this product in homes, garages,
basements, crawlspaces, sheds, or other closed
spaces, even if you use fans or open doors and
windows for ventilation. After the operation of this
product, carbon monoxide can quickly collect in these
spaces and stay for hours.
• ALWAYS put this product downwind and point the
engine exhaust away from occupied spaces.
WARNING
During operation, the engine and muffler become hot. If
you touch a hot engine, thermal burns can occur.
Combustible materials, such as leaves, grass and brush,
can catch fire.
• Before you touch the engine or muffler, stop the engine
and wait two (2) minutes. Make sure that the engine and
muffler are safe to touch.
• Remove debris from the muffler and engine.
WARNING
Accidental engine spark can cause an electric shock, fire
or explosion and could result in entanglement, traumatic
amputation or laceration.
Before you make adjustments or repairs:
• Disconnect all spark plug wires and keep them away
from the spark plugs.
• Disconnect the battery wire from the negative battery
terminal (only engines with electric start).
• Use only the correct tools.
When you check for spark:
• Use an approved spark plug tester.
• Do not check for spark with the spark plug removed.
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WARNING
Rotating parts can entangle hands, feet, hair, clothing,
or accessories and result in traumatic amputation or
laceration.
• Operate equipment with the guards correctly installed.
• Keep hands and feet away from rotating parts.
• Remove jewelry and make sure that long hair is away
from all rotating parts.
• Do not wear loose clothes or items that could become
caught.
WARNING
Fuel and its vapors are flammable and explosive. Fire or
explosion could result in burns or death.
Fuel Storage
• Because pilot lights or other ignition sources can cause
explosions, keep fuel or equipment away from furnaces,
stoves, water heaters or other appliances that have pilot
lights.
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2
SECTION 2 - DIAGNOSTIC INTRODUCTION
DIAGNOSTIC INTRODUCTION ------------------------------------------------------------------------------------------------------------------------ 12
Preliminary Instructions ------------------------------------------------------------------------------------------------------------------------------ 12
On-Board Diagnostic (OBD) System Check ----------------------------------------------------------------------------------------------------12
Diagnostic Trouble Codes (DTCs) ---------------------------------------------------------------------------------------------------------------- 12
Malfunction Indicator Lamp (MIL) ----------------------------------------------------------------------------------------------------------------- 12
Data Link Connector (DLC) -------------------------------------------------------------------------------------------------------------------------12
Using the Diagnostic Tool and Software to Read/Clear DTCs ----------------------------------------------------------------------------13
Back Probe Connector Terminals -----------------------------------------------------------------------------------------------------------------14
Avoid ECM Damage ---------------------------------------------------------------------------------------------------------------------------------- 14
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Diagnostic Introduction
Preliminary Instructions
Prior to starting any diagnostic, repair or maintenance
operation. Make sure you are familiar withALL safety
warnings and procedures as outlined in SECTION 1 -
SAFETY AND GENERAL INFORMATION - General Safety
Messages.
ALWAYS wear safety glasses and gloves while performing
any diagnostic, maintenance or repair operation.
On-Board Diagnostic (OBD) System Check
The basic steps of any diagnosis are as follows:
1. Observe the Malfunction Indicator Lamp (MIL) with
engine running. If MIL is illuminated, then current
Diagnostic Trouble Codes (DTCs) are present.
2. Read DTC(s) using the Diagnostic Tool.
3. To diagnose system problem(s), proceed to the
applicable Diagnostic Table(s) in SECTION 3 -
TROUBLESHOOTING DTCs.
4. Once the problem is located and corrected through repair
or replacement of faulty components, clear DTC(s) using
the Diagnostic Tool.
For information on the location or replacement of
specific components, see SECTION 6 - REMOVAL/
INSTALLATION.
5. Start and run engine to validate repairs. Observe MIL to
verify that no DTCs are set.
6. If no DTCs are set, but engine performance
issues exist, see SECTION 5 - SYMPTOMSAND
TROULESHOOTING.
Diagnostic Trouble Codes (DTCs)
The ECM receives voltage signals from multiple sensors.
Each sensor functions within an established set of
parameters.
When a malfunction or fault condition occurs, a change in the
signal voltage alerts the ECM that the sensor is functioning
outside its operating “window,” a DTC is set and stored in
ECM memory, and the MIL is illuminated.
A default value temporarily replaces the erroneous sensor
value to restore engine performance until the problem is
corrected.
Suspect Parameter Number (SPN) and Failure Mode
Indicator (FMI)
The J1939 protocol transmits each DTC in a number of parts,
two of which are the Suspect Parameter Number (SPN) and
the Failure Mode Indicator (FMI).
While the SPN indicates the source of the problem, such as
a specific electrical circuit or electrical component, the FMI
indicates the type of condition or event that has occurred.
A helpful analogy is to view the SPN as a zip code which
brings you to the problem area, while the FMI is the street
address. For example, SPN 105 indicates that an issue exists
with the Manifold Air Temperature (MAT) Sensor, while FMI 3
indicates that the sensor signal voltage is high/open.
For a list of all DTCs and their respective SPN/FMI
components, see DIAGNOSTIC TROUBLE CODES (DTCs)
in SECTION 3 - TROUBLESHOOTING DTCs.
Malfunction Indicator Lamp (MIL)
As a bulb and diagnostic system check, the MIL illuminates at
Ignition ON, Engine OFF. When the engine is started, the MIL
is extinguished if no current fault condition exists.
If the MIL remains illuminated, it is an indication that a current
DTC is stored. If the fault should correct itself, as in an
intermittent condition, the MIL is extinguished after a ten
second delay. The DTC remains stored in ECM memory as a
historic code until cleared by the technician. The MIL does not
indicate the existence of only historic codes.
Data Link Connector (DLC)
The DLCprovides for direct communication with the ECM. By
plugging theDiagnostic Tool into the 6-pin connector in the
EFI wire harness, the DTCs stored in ECM memory can be
read and cleared.and diagnostic functions can be accessed.
Accessing the DLC requires removal of the engine side cover
connector cover and the DLC protective cap. The procedure
is as follows:
1. Remove the connector cover from the side cover. Lift the
tab of the snap latch (A, Figure 1)and rotate the cover
away from the engine to remove.
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2. Remove the DLC from the wire harness clip (A, Figure
2).
2
3. Remove the DLC protective cap. Pull out the locking tab
(A, Figure 3) and press the connector tab while pulling
the protective cap (B) away from the DLC.
3
NOTE: Make sure to reinstall the DLC protective cap when
diagnostic procedures are concluded.
Using the Diagnostic Tool and Software to Read/
Clear DTCs
1. Open the Briggs & Stratton Diagnostic Tool Application
by selecting the icon on the desktop.
2. After entering the User Name and Password, click Log
In.
NOTE: If this is your first time using the Diagnostic Tool and
Software, refer to the Briggs & Stratton EFI Diagnostic Tool
Software User Manual for installation and setup instructions.
3. Obtain Briggs & Stratton Diagnostic Tool (Part No.
19636) with USB and Interface cables.
4. Connect one end of the USB cable to the Diagnostic Tool
and the other end to the USB port on the laptop.
5. Connect one end of the Interface cable to the Diagnostic
Tool and the other end to the DLC on the EFI harness.
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6. Turn Ignition ON, Engine OFF.
The Diagnostic Tool can take up to 30 seconds to
connect to the engine. Once established, the connection
indicator light (A, Figure 4) becomes solid green and
displays the name of the connected device.
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7. Select the Dashboard icon (B) to view the Dashboard.
8. The CHECK ENGINE light (C) is red if a current fault
code is present.
9. Observe the Current codes display. Hover the cursor
over theblue hyperlink (D) to display a description of
the SPN fault code. Click on the hyperlink to read the
associated FMI (E).
10. Click Clear (F) to erase both current and historic DTCs.
11. Turn Ignition OFF.
12. Wait ten seconds, and then disconnect the Diagnostic
Tool cables and power supply.
NOTE: While the Diagnostic Tool provides “live” data for
analysis, it is not a standalone diagnostic tool for resolving
DTCs, but must be used in conjunction with the Diagnostic
Tables in this manual for the most efficient and effective
diagnosis.
Back Probe Connector Terminals
Do not insert probes into terminals on the mating side of
any connector. The diameter of the test probes can damage
terminals.
1. Obtain a digital volt ohm meter (DVOM) and a back
probe wire set.
2. Carefully slide metal pin on probe between the rubber
seal and wire insulation on the back side (wire end) of
the connector.
3. Gently push the pin in until it stops. Stop pushing when
the pin “bottoms out,” or when the plastic sheath is very
close to the connector housing.
DO NOT force the pin into the connector as terminal and/
or probe pin damage can occur. Probe travel may be
stopped by contact with insulation or core crimps. Try
again after removing and re-positioning probe pin.
IMPORTANT:
• Use care to avoid deforming connector terminals,
either by forcing the probe too far into the cavity or
by using a probe that is too large. If terminal damage
is suspected, test for proper terminal contact.
• A deformed terminal can cause a poor connection
resulting in intermittent problems or even complete
component failure. Do not use paper clips or
other substitute devices as they also can damage
terminals.
• Do not probe through connector seals, wire
insulation, secondary ignition wires, boots, etc.
Damage can occur that is not readily apparent and
tiny holes can result in water intrusion, which leads
to corrosion and eventual component failure.
Avoid ECM Damage
A surge in voltage, current or both, is called a voltage spike.
Voltage spikes can cause major damage to the ECM.
To avoid ECM failure due to accidentally induced voltage
spikes, always observe the following precautions:
• Do not start engine if battery cable connections are
loose.
• Do not use a battery charger to start engine.
• Turn Ignition OFF before disconnecting and/or
connecting battery cables.
• When disconnecting battery, always disconnect battery
negative (-) cable first.
• When connecting battery, always connect battery
positive (+) cable first.
• When charging battery, turn Ignition OFF and remove
battery negative cable (black) from battery negative (-)
terminal.
• If electric welding on vehicle, remove battery negative
cable (black) from battery negative (-) terminal, and
disconnect the ECM electrical connector(s).
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3
SECTION 3 - TROUBLESHOOTING DTCs
DIAGNOSTIC TROUBLE CODES (DTCS) ---------------------------------------------------------------------------------------------------------- 18
MODEL 25E300 EFI COMPONENT LOCATIONS -------------------------------------------------------------------------------------------------19
PRELIMINARY INSTRUCTIONS ----------------------------------------------------------------------------------------------------------------------- 20
CAN BUS TROUBLESHOOTING ---------------------------------------------------------------------------------------------------------------------- 20
Check Voltages ---------------------------------------------------------------------------------------------------------------------------------------- 20
Check Waveforms ------------------------------------------------------------------------------------------------------------------------------------- 21
TEST PROCEDURES ------------------------------------------------------------------------------------------------------------------------------------- 22
VERIFY ENGINE CONTROL MODULE (ECM) POWERS UP --------------------------------------------------------------------------------- 23
Circuit Description - ECM Power ------------------------------------------------------------------------------------------------------------------23
Check ECM Power and Ground -------------------------------------------------------------------------------------------------------------------23
ECM Connector Loom Cover Removal ----------------------------------------------------------------------------------------------------------24
SPN 51 THROTTLE POSITION SENSOR (TPS) --------------------------------------------------------------------------------------------------25
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 25
Possible FMIs - SPN 51 -----------------------------------------------------------------------------------------------------------------------------25
SPN 91 SPEED LEVER ---------------------------------------------------------------------------------------------------------------------------------- 26
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 26
Possible FMIs - SPN 91 -----------------------------------------------------------------------------------------------------------------------------26
Speed vs Voltage Table ----------------------------------------------------------------------------------------------------------------------------- 27
SPN 91, FMI 3: Signal Voltage High -------------------------------------------------------------------------------------------------------------28
SPN 91, FMI 4: Signal Voltage Low/Open ----------------------------------------------------------------------------------------------------- 29
SPN 98 LOW OIL LEVEL -------------------------------------------------------------------------------------------------------------------------------- 30
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 30
Possible FMIs -------------------------------------------------------------------------------------------------------------------------------------------30
SPN 98, FMI 1: Low Oil Level Error ------------------------------------------------------------------------------------------------------------- 30
SPN 102 MANIFOLD ABSOLUTE PRESSURE SENSOR (MAP) ----------------------------------------------------------------------------- 31
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 31
Possible FMIs - SPN 102 --------------------------------------------------------------------------------------------------------------------------- 31
SPN 102, FMI 3: Signal Voltage High -----------------------------------------------------------------------------------------------------------32
SPN 102, FMI 4: Signal Voltage Low/Open ----------------------------------------------------------------------------------------------------32
SPN 105 INTAKE AIR TEMPERATURE SENSOR (IAT) ---------------------------------------------------------------------------------------- 33
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 33
Possible FMIs - SPN 105 --------------------------------------------------------------------------------------------------------------------------- 33
SPN 105, FMI 3: Signal Voltage High/Open ---------------------------------------------------------------------------------------------------34
SPN 105, FMI 4: Signal Voltage Low ------------------------------------------------------------------------------------------------------------34
SPN 110 ENGINE HEAD TEMPERATURE SENSOR (EHT) -----------------------------------------------------------------------------------35
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 35
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Possible FMIs - SPN 110 --------------------------------------------------------------------------------------------------------------------------- 35
SPN 110, FMI 3: Voltage High/Open ------------------------------------------------------------------------------------------------------------ 36
SPN 110, FMI 4: Voltage Low ---------------------------------------------------------------------------------------------------------------------36
SPN 158 IGNITION KEY VOLTAGE ------------------------------------------------------------------------------------------------------------------ 37
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 37
Possible FMIs - SPN 158 --------------------------------------------------------------------------------------------------------------------------- 37
SPN 158, FMI 3: Voltage High -------------------------------------------------------------------------------------------------------------------- 37
SPN 158, FMI 4: Voltage Low ---------------------------------------------------------------------------------------------------------------------38
SPN 168 BATTERY VOLTAGE -------------------------------------------------------------------------------------------------------------------------39
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 39
Possible FMIs - SPN 168 --------------------------------------------------------------------------------------------------------------------------- 39
SPN 168, FMI 3: Voltage High -------------------------------------------------------------------------------------------------------------------- 39
SPN 168, FMI 4: Voltage Low ---------------------------------------------------------------------------------------------------------------------40
SPN 190 ENGINE OVERSPEED DETECTION ---------------------------------------------------------------------------------------------------- 41
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 41
Possible FMIs - SPN 190 --------------------------------------------------------------------------------------------------------------------------- 41
SPN 633 VAPOR DETECTION IN FDI --------------------------------------------------------------------------------------------------------------- 42
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 42
Possible FMIs - SPN 633 --------------------------------------------------------------------------------------------------------------------------- 42
SPN 633, FMI 8: Vapors Detected in FDI During RUN State ----------------------------------------------------------------------------- 42
SPN 633, FMI 11: Vapors Detected in FDI During CRANKING State ------------------------------------------------------------------ 42
SPN 636 CRANKSHAFT WRONG TOOTH NUMBER ------------------------------------------------------------------------------------------- 43
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 43
Possible FMIs - SPN 636 --------------------------------------------------------------------------------------------------------------------------- 43
SPN 636, FMI 2: Not Enough Teeth Detected ------------------------------------------------------------------------------------------------ 43
SPN 637 MISSING CRANK SENSOR (CKP) -------------------------------------------------------------------------------------------------------44
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 44
Possible FMIs - SPN 637 --------------------------------------------------------------------------------------------------------------------------- 44
SPN 637, FMI 7: Missing Crank Sensor Signal -----------------------------------------------------------------------------------------------44
SPN 639 CAN BUS OFFLINE -------------------------------------------------------------------------------------------------------------------------- 45
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 45
Possible FMIs - SPN 639 --------------------------------------------------------------------------------------------------------------------------- 45
SPN 651 FUEL INJECTOR ------------------------------------------------------------------------------------------------------------------------------ 46
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 46
Possible FMIs - SPN 651 --------------------------------------------------------------------------------------------------------------------------- 46
SPN 651, FMI 3: Voltage High/Open ------------------------------------------------------------------------------------------------------------ 47
SPN 651, FMI 4: Voltage Low ---------------------------------------------------------------------------------------------------------------------48
SPN 818 VOLTAGE PROTECTION -------------------------------------------------------------------------------------------------------------------49
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 49
Possible FMIs - SPN 818 --------------------------------------------------------------------------------------------------------------------------- 49
SPN 818, FMI 3: Short 5V Supply High -------------------------------------------------------------------------------------------------------- 49
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SPN 818, FMI 4: Short 5V Supply Low --------------------------------------------------------------------------------------------------------- 50
SPN 1110 ENGINE OVER TEMPERATURE FOR MAXIMUM ALLOWED TIME --------------------------------------------------------- 51
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 51
Possible FMIs - SPN 1110 ------------------------------------------------------------------------------------------------------------------------- 51
SPN 1110, FMI 0: Head Over Temperature --------------------------------------------------------------------------------------------------- 51
SPN 1268 CYLINDER 1 IGNITION COIL ------------------------------------------------------------------------------------------------------------52
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 52
Possible FMIs - SPN 1268 ------------------------------------------------------------------------------------------------------------------------- 52
SPN 1268, FMI 3: Short to High/Open ----------------------------------------------------------------------------------------------------------53
SPN 1268, FMI 4: Short Low ---------------------------------------------------------------------------------------------------------------------- 54
SPN 1569 ENGINE OVER TEMPERATURE WHILE RUNNING ------------------------------------------------------------------------------ 55
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 55
Possible FMIs - SPN 1569 ------------------------------------------------------------------------------------------------------------------------- 55
SPN 1569, FMI 16: Head Over Temperature --------------------------------------------------------------------------------------------------55
SPN 5419 ELECTRONIC THROTTLE CONTROL (ETC) --------------------------------------------------------------------------------------- 56
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 56
Possible FMIs - SPN 5419 ------------------------------------------------------------------------------------------------------------------------- 56
SPN 6805 DIAGNOSTIC --------------------------------------------------------------------------------------------------------------------------------- 57
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 57
Possible FMIs - SPN 6805 ------------------------------------------------------------------------------------------------------------------------- 57
SPN 6805, FMI 16: Engine Over Temperature ----------------------------------------------------------------------------------------------- 57
SPN 7753 STARTER MOTOR INPUT SIGNAL ---------------------------------------------------------------------------------------------------- 58
Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 58
Possible FMIs - SPN 7753 ------------------------------------------------------------------------------------------------------------------------- 58
SPN 7753, FMI 3: Input Signal Shorted High ------------------------------------------------------------------------------------------------- 59
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Diagnostic Trouble Codes (DTCs)
SPN Component FMI Description
2 Intermittent Fail
3 Signal Voltage High
51 Throttle Position Sensor (TPS)
4 Signal Voltage Low/Open
3 Signal Voltage High91 Analog Speed Lever
4 Signal Voltage Low/Open
98 Low Oil Level Sensor 1 Low Oil Level Error
3 Signal Voltage High102 Manifold Absolute Pressure (MAP) Sensor
4 Signal Voltage Low/Open
2 Intermittent Fail
3 Signal Voltage High/Open
105 Intake Air Temperature (IAT) Sensor
4 Signal Voltage Low
2 Intermittent Fail
3 Voltage High/Open
110 Engine Cylinder Head Temperature (EHT) Sensor
4 Voltage Low
3 Voltage High158 Ignition Key Voltage
4 Voltage Low
3 Voltage High168 Battery Voltage
4 Voltage Low
190 Engine Overspeed Detection 15 Over Speed Detected
8 Vapors Detected In FDI During RUN STATE633 Vapor Detection
11 Vapors Detected In FDI
During CRANKING STATE
2 Not Enough Teeth Detected636 Crankshaft Wrong Tooth Number
8 Additional Tooth Detected
637 Missing Crank Sensor (CKP) 7 Missing Crank Sensor Signal
639 CAN Bus Offline 19 Data Error
3 Voltage High/Open651 Fuel Injector #1
4 Voltage Low
3 5V Supply Shorted High
4 5V Supply Shorted Low
818 Voltage Protection
16 Over Temperature
1110 Engine Over-Temperature 0 Engine Cylinder Head Over Maximum
Temperature For Maximum Allowed Time
3 Circuit Shorted High/Open1268 Cylinder #1 Ignition
4 Circuit Shorted Low
1569 Engine Over-Temperature 16 Cylinder Head Over Maximum
Temperature While Running
3 ETC Driver Pin 1 and/or
Pin 2 Circuit Shorted High
4 ETC Driver Pin 1 and/
or Pin 2 Circuit Shorted Low
5 ETC Driver Circuit Open
6 ETC Driver Shorted Between Pin 1 & 2
8 Pulse Width Modulation Out of Range
15 ETC Driver Over Temperature WARNING
5419 Electronic Throttle Control (ETC)
16 ETC Driver Over Temperature
6805 Engine Over Temperature 16 SPN 6805 Appears With SPN 1569. SPN
6805 Will Trigger an Engine Speed Derate.
7753 Starter Motor 3 Input Signal Circuit Shorted High
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Model 25E300 EFI Component Locations
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Preliminary Instructions
Prior to starting any diagnostic, repair or maintenance
operation. Make sure you are familiar withALL safety
warnings and procedures as outlined in SECTION 1 -
SAFETY AND GENERAL INFORMATION - General Safety
Messages.
ALWAYS wear safety glasses and gloves while performing
any diagnostic, maintenance or repair operation.
CAN BUS Troubleshooting
Troubleshooting DTCs may not always get to the real source of the problem, as there can be instances where the problem
originates with the CAN bus. Bad connections can result in faulty communications with the ECM resulting in a faulty diagnosis.
Check Voltages
Step Action
11. Turn Ignition OFF.
2. Back probe CAN Hi terminal C (Yellow wire) at the DLC.
3. Connect terminal C back probe to red meter test lead on DVOM.
4. Connect black meter test lead on DVOM to ground.
5. Turn Ignition ON, Engine OFF.
6. Compare voltage to table below.
21. Turn Ignition OFF.
2. Back probe CAN Lo terminal D (Green wire) at the DLC.
3. Connect terminal D back probe to red meter test lead on DVOM.
4. Connect black meter test lead on DVOM to ground.
5. Turn Ignition ON, Engine OFF.
6.Compare voltage totablebelow.
DLC
Can Bus
Circuits
Sleep Idle
(Recessive)
KOEO
Active Bus CAN Lo Short
to Ground
CANHi Short
to Ground
CANLo Short
to Power
CANHi Short
to Power
CANHi Short
toCANLo
CAN Lo (-) 0 VDC 2.5 VDC 1.5 VDC
– 2.5 VDC
0 VDC 0-0.5 VDC 5-12 VDC Below
0.75 VDC
2.45 VDC
CAN Hi (+) 0 VDC 2.5 VDC 2.5 VDC
– 3.5 VDC
0-0.5 VDC 0 V Below
0.75 VDC
5-12 VDC 2.45 VDC
Resistance Test 120 Ohms: Between both CAN HI and LO
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Check Waveforms
It is generally recommended that an overall bus check be performed using an oscilloscope. An inexpensive oscilloscope, and a
simple multi-meter using the ohmmeter option can give valuable information on the health of the CAN bus.
The CAN electrical signals can be viewed by connecting the oscilloscope to terminal C (CAN Hi) and terminal D (CAN Lo) on
the DLC. Healthy CAN signal waveforms will appear similar to that shown in A of the figure below. A CAN bus with a corrupted
signal is shown in B.
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