
check the shared circuits for possible problems
before continuing (i.e. Sensor Grounds or 5-Volt
Supply circuits). Refer to the appropriate wiring
diagrams to identify shared circuits.
MASS AIR FLOW SENSOR SIGNAL VOLTAGE
TOO HIGH
MASS AIR FLOW SENSOR SIGNAL VOLTAGE
TOO LOW
MASS AIR FLOW SENSOR SUPPLY VOLTAGE
TOO HIGH OR LOW
MASS AIR FLOW SENSOR PLAUSIBILITY
MASS AIR FLOW SENSOR SIGNAL PLAUSI-
BILITY POSITIVE AREA
BAROMETRIC PRESSURE CIRCUIT SIGNAL
VOLTAGE TOO HIGH
BAROMETRIC PRESSURE CIRCUIT SIGNAL
VOLTAGE TOO LOW
INTAKE AIR TEMP SENSOR SIGNAL VOLT-
AGE TOO HIGH
INTAKE AIR TEMP SENSOR SIGNAL VOLT-
AGE TOO LOW
ENGINE COOLANT TEMP SENSOR SIGNAL
VOLTAGE TOO HIGH
ENGINE COOLANT TEMP SENSOR SIGNAL
VOLTAGE TOO LOW
FUEL PRESS SENSOR CIRCUIT MALF SIG-
NAL VOLTAGE TOO HIGH
FUEL PRESS SENSOR CIRCUIT MALF SIG-
NAL VOLTAGE TOO LOW
FUEL PRESS SENSOR CIRCUIT MALF SUP-
PLY VOLTAGE TOO HIGH OR LOW
OIL TEMP SENSOR CIRCUIT MALF SIGNAL
VOLTAGE TOO HIGH
OIL TEMP SENSOR CIRCUIT MALF SIGNAL
VOLTAGE TOO LOW
CYLINDER 1-INJECTOR CIRCUIT OVERCUR-
RENT HIGH SIDE
CYLINDER 1-INJECTOR CIRCUIT OVERCUR-
RENT LOW SIDE
CYLINDER 1-INJECTOR CIRCUIT LOAD
DROP
CYLINDER 1-INJECTOR CIRCUIT CURRENT
DECREASE
CYLINDER 2-INJECTOR CIRCUIT OVERCUR-
RENT HIGH SIDE
CYLINDER 2-INJECTOR CIRCUIT OVERCUR-
RENT LOW SIDE
CYLINDER 2-INJECTOR CIRCUIT LOAD
DROP
CYLINDER 2-INJECTOR CIRCUIT CURRENT
DECREASE
CYLINDER 3-INJECTOR CIRCUIT OVERCUR-
RENT HIGH SIDE
CYLINDER 3-INJECTOR CIRCUIT OVERCUR-
RENT LOW SIDE
CYLINDER 3-INJECTOR CIRCUIT LOAD
DROPCYLINDER 3-INJECTOR CIRCUIT CURRENT
DECREASE
CYLINDER 4-INJECTOR CIRCUIT OVERCUR-
RENT HIGH SIDE
CYLINDER 4-INJECTOR CIRCUIT OVERCUR-
RENT LOW SIDE
CYLINDER 4-INJECTOR CIRCUIT LOAD
DROP
CYLINDER 4-INJECTOR CIRCUIT CURRENT
DECREASE
BOOST PRESSURE SENSOR SIGNAL VOLT-
AGE TOO HIGH
BOOST PRESSURE SENSOR SIGNAL VOLT-
AGE TOO LOW
BOOST PRESSURE SENSOR SUPPLY VOLT-
AGE TOO HIGH OR LOW
BOOST PRESSURE SENSOR PLAUSIBILITY
CKP POSITION SENSOR CIRCUIT OVER-
SPEED RECOGNITION
CKP POSITION SENSOR CIRCUIT DYNAMIC
PLAUSIBILITY
CKP POSITION SENSOR CIRCUIT STATIC
PLAUSIBILITY
CMP POSITION SENSOR CIRCUIT CMP/CKP
SYNC FAILURE
CMP POSITION SENSOR CIRCUIT DYNAMIC
PLAUSIBILITY
CMP POSITION SENSOR CIRCUIT STATIC
PLAUSIBILITY
CMP POSITION SENSOR CIRCUIT SIGNAL
FREQUENCY TOO HIGH
CMP POSITION SENSOR CIRCUIT FUEL
SHUT-OFF ACTIVATED
GLOW PLUG CIRCUIT A SHORT CIRCUIT
GLOW PLUG CIRCUIT A OPEN CIRCUIT
EGR SOLENOID CIRCUIT OPEN CIRCUIT
EGR SOLENOID CIRCUIT SHORT CIRCUIT
EGR SOLENOID CIRCUIT IMPROPER FLOW
FAN 1 CONTROL CIRCUIT OPEN CIRCUIT
FAN 1 CONTROL CIRCUIT SHORT CIRCUIT
FAN 2 CONTROL CIRCUIT OPEN CIRCUIT
FAN 2 CONTROL CIRCUIT SHORT CIRCUIT
VEHICLE SPEED SENSOR SIGNAL VOLTAGE
TOO HIGH
VEHICLE SPEED SENSOR FREQUENCY TOO
HIGH
VEHICLE SPEED SENSOR HIGH LEVEL DU-
RATION
VEHICLE SPEED SENSOR PLAUSIBILITY
BATTERY TEMP SENSOR SIGNAL VOLTAGE
TOO HIGH
BATTERY TEMP SENSOR SIGNAL VOLTAGE
TOO LOW
OIL PRESS SENSOR CKT MALF PLAUSIBIL-
ITY
4
GENERAL INFORMATION

A/C PRESSURE SENSOR CIRCUIT SIGNAL
VOLTAGE TOO HIGH
A/C PRESSURE SENSOR CIRCUIT SIGNAL
VOLTAGE TOO LOW
A/C PRESSURE SENSOR CIRCUIT SUPPLY
VOLTAGE TOO HIGH OR LOW
A/C PRESSURE SENSOR CIRCUIT PLAUSI-
BILITY
SYSTEM VOLTAGE TOO HIGH
SYSTEM VOLTAGE TOO LOW
S/C SWITCH SIGNAL CIRCUIT SIGNAL VOLT-
AGE TOO HIGH
S/C SWITCH SIGNAL CIRCUIT SIGNAL VOLT-
AGE TOO LOW
S/C SWITCH SIGNAL CIRCUIT PLAUSIBILITY
ECM ERROR RECOVERY HAS OCCURRED
ECM ERROR REDUNDANT OVERRUN MONI-
TORING
ECM ERROR GATE ARRAY - QUANTITY STOP
ECM ERROR GATE ARRAY - COMMUNICA-
TION
ECM ERROR - COMMUNICATION NOT VERI-
FIED
STARTER RELAY CIRCUIT OPEN CIRCUIT
STARTER RELAY CIRCUIT SHORT CIRCUIT
GENERATOR FIELD CONTROL MALF BAT-
TERY VOLTAGE TOO HIGH
GENERATOR FIELD CONTROL MALF BAT-
TERY VOLTAGE TOO LOW
GENERATOR FIELD CONTROL MALF OPEN
CIRCUIT
GENERATOR FIELD CONTROL MALF SHORT
CIRCUIT
GENERATOR FIELD CONTROL MALF
CHARGING VOLTS TOO LOW
GENERATOR FIELD CONTROL MALF BAT-
TERY VOLTAGE DEVIATION TOO HIGH
GENERATOR FIELD CONTROL MALF BAT-
TERY VOLTAGE DEVIATION TOO LOW
GENERATOR FIELD CONTROL MALF UN-
STABLE CURRENT
SENSOR REFERENCE VOLTAGE A CKT VOLT-
AGE TOO HIGH
SENSOR REFERENCE VOLTAGE A CKT VOLT-
AGE TOO LOW
SENSOR REFERENCE VOLTAGE B CKT
VOLTAGE TOO HIGH
SENSOR REFERENCE VOLTAGE B CKT
VOLTAGE TOO LOW
A/C CLUTCH RELAY CIRCUIT OPEN CIRCUIT
A/C CLUTCH RELAY CIRCUIT SHORT CIR-
CUIT
ECM/PCM RELAY CONTROL CIRCUIT SHUTS
OFF TOO EARLY
ECM/PCM RELAY CONTROL CIRCUIT SHUTS
OFF TOO LATE
BRAKE SWITCH SIGNAL CIRCUITS INCOR-
RECT CAN MESSAGEBRAKE SWITCH SIGNAL CIRCUITS PLAUSI-
BILITY WITH REDUNDANT CONTACT
BRAKE SWITCH SIGNAL CIRCUITS PLAUSI-
BILITY WITH REDUNDANT CONTACT AFTER
INITIALIZATION
CLUTCH UPSTOP SWITCH PERF PLAUSIBIL-
ITY
CLUTCH UPSTOP SWITCH PERF PLAUSIBIL-
ITY WITH P/N SWITCH
FUEL RAIL PRESSURE MALFUNCTION
PRESSURE TOO HIGH - LIMITATION
FUEL RAIL PRESSURE MALFUNCTION
PRESSURE TOO LOW
FUEL RAIL PRESSURE MALFUNCTION SO-
LENOID OPEN
FUEL RAIL PRESSURE MALFUNCTION
LEAKAGE DETECTED
FUEL PRESSURE SOLENOID OPEN CIRCUIT
FUEL PRESSURE SOLENOID SHORT CIR-
CUIT
FUEL PRESSURE SOLENOID PLAUSIBILITY
IN AFTER-RUN
CALCULATED INJECTOR VOLTAGE - VOLT-
AGE 1 TOO LOW
CALCULATED INJECTOR VOLTAGE - VOLT-
AGE 2 TOO LOW
BATTERY SENSE LINE 1 VOLTAGE TOO
HIGH
BATTERY SENSE LINE 1 VOLTAGE TOO LOW
FUEL PRESS REG CURRENT CONTROL SIG-
NAL TOO HIGH
FUEL PRESS REG CURRENT CONTROL SIG-
NAL TOO LOW
GENERATOR FIELD CURRENT TOO HIGH
GENERATOR FIELD CURRENT TOO LOW
CAPACITOR VOLTAGE 1 VOLTAGE TOO HIGH
CAPACITOR VOLTAGE 1 VOLTAGE TOO LOW
CAPACITOR VOLTAGE 2 VOLTAGE TOO HIGH
CAPACITOR VOLTAGE 2 VOLTAGE TOO LOW
IGNITION SWITCH PLAUSIBILITY
AFTER RUN SHUT OFF ERROR - ZERO
QUANTITY
AFTERRUN SHUT OFF ERROR - INJ. POWER-
STAGE
VOLTAGE REGULATOR SIGNAL VOLTAGE
TOO HIGH
VOLTAGE REGULATOR SIGNAL VOLTAGE
TOO LOW
MIL/DIAG LAMP VIA J1850 BUS IN FRAME
RESPONSE ERROR
MIL/DIAG LAMP VIA J1850 BUS - STATUS
ERROR
J1850 COMMUNICATION BUS SHORT TO
VOLTAGE
J1850 COMMUNICATION BUS SHORT TO
GROUND
J1850 COMMUNICATION BUS TRANSMIT
BUFFER OVERRUN
5
GENERAL INFORMATION

J1850 COMMUNICATION BUS SPI ERROR
J1850 COMMUNICATION BUS RECEIVE TIME-
OUT
J1850 COMMUNICATION BUS UNAUTHO-
RIZED RESET
EEPROM PLAUSIBILITY CHECKSUM ERROR
EEPROM PLAUSIBILITY VIN CHECKSUM
ERROR
EEPROM PLAUSIBILITY COMMUNICATION
ERROR
EEPROM PLAUSIBILITY WRITE ERROR
EEPROM PLAUSIBILITY VARIATION NUM-
BER ERROR
EEPROM PLAUSIBILITY CODE WORD IN-
CORRECT OR MISSING
SKIM SYSTEM SKIM ERROR
SKIM SYSTEM WRITE ACCESS TO EEPROM
FAILURE
SKIM SYSTEM INVALID SECRET KEY IN EE-
PROM
SKIM SYSTEM KEY COMMUNICATION
TIMED OUT
SKIM SYSTEM INVALID KEY CODE RE-
CEIVED
EEPROM RECOVERY OCCURRED
EEPROM REDUNDANT OVERRUN MONI-
TORING
EEPROM QUANTITY STOP
EEPROM COMMUNICATION ERROR
EEPROM COMMUNICATION NOT VERIFIED
ACC PEDAL POSITION SENSOR 1 CKT SIG-
NAL VOLTAGE TOO HIGH
ACC PEDAL POSITION SENSOR 1 CKT SIG-
NAL VOLTAGE TOO LOW
ACC PEDAL POSITION SENSOR 1 CKT SUP-
PLY VOLTAGE TOO HIGH OR LOW
ACC PEDAL POSITION SENSOR 1 CKT PLAU-
SIBILITY WITH POTENTIOMETER
ACC PEDAL POSITION SENSOR 1 CKT PLAU-
SIBILITY WITH BRAKE SWITCH
ACC PEDAL POSITION SENSOR 1 CKT PLAU-
SIBILITY
3.3.4 SKIM DIAGNOSTIC TROUBLE CODES
ANTENNA FAILURE
COP FAILURE
EEPROM FAILURE
PCM STATUS FAILURE
INTERNAL FAULT
RAM FAILURE
ROLLING CODE FAILURE
SERIAL LINK EXTERNAL FAULT
SERIAL LINK INTERNAL FAULT
STACK OVERFLOW FAILURE
TRANSPONDER COMMUNICATION FAILURE
TRANSPONDER CRC (CYCLIC REDUN-
DANCY CHECK) FAILURE
TRANSPONDER ID MISMATCHTRANSPONDER RESPONSE MISMATCH
VIN MISMATCH
3.3.5 HANDLING NO TROUBLE CODE
PROBLEMS
After reading Section 3.0 (System Description
and Functional Operation), you should have a bet-
ter understanding of the theory and operation of the
on-board diagnostics, and how this relates to the
diagnosis of a vehicle that may have a driveability-
related symptom or complaint.
3.4 USING THE DRBIIIT
Refer to the DRBIIItuser 's guide for instructions
and assistance with reading the DTCs, erasing the
DTCs, lab scope usage and other DRBIIItfunc-
tions.
3.4.1 DRBIIITDOES NOT POWER UP
If the LEDs do not light or no sound is emitted at
start up, check for loose cable connections or a bad
cable. Check the vehicle battery voltage at data link
connector cavity 16. A minimum of 11.0 volts is
required to adequately power the DRB. Check for
proper ground connection at data link connector
cavities 4 and 5.
If all connections are proper between the
DRBIIItand the vehicle or other devices, and the
vehicle battery is fully charged, an inoperative
DRBIIItmay be the result of a faulty cable or
vehicle wiring. For a blank screen, refer to the
appropriate diagnostic manual.
3.4.2 DISPLAY IS NOT VISIBLE
Low temperatures will affect the visibility of the
display. Adjust the contrast to compensate for this
condition.
6
GENERAL INFORMATION

4.0 DISCLAIMERS, SAFETY,
WARNINGS
4.1 DISCLAIMERS
All information, illustrations, and specifications
contained in this manual are based on the latest
information available at the time of publication.
The right is reserved to make changes at any time
without notice.
4.2 SAFETY
4.2.1 TECHNICIAN SAFETY INFORMATION
WARNING: ENGINES PRODUCE CARBON
MONOXIDE THAT IS ODORLESS, CAUSES
SLOWER REACTION TIME, AND CAN LEAD
TO SERIOUS INJURY. WHEN THE ENGINE IS
OPERATING, KEEP SERVICE AREAS WELL
VENTILATED OR ATTACH THE VEHICLE
EXHAUST SYSTEM TO THE SHOP EXHAUST
REMOVAL SYSTEM.
Set the parking brake and block the wheels before
testing or repairing the vehicle. It is especially
important to block the wheels on front wheel drive
vehicles; the parking brake does not hold the drive
wheels.
When servicing a vehicle, always wear eye pro-
tection, and remove any metal jewelry such as
watchbands or bracelets that might make electrical
contact.
When diagnosing a powertrain system problem,
it is important to follow approved procedures where
applicable. These procedures can be found in the
service manual. Following these procedures is very
important to the safety of individuals performing
diagnostic tests.
4.2.2 VEHICLE PREPARATION FOR
TESTING
Make sure the vehicle being tested has a fully
charged battery. If it does not, false diagnostic codes
or error messages may occur.
4.2.3 SERVICING SUB-ASSEMBLIES
Some components of the powertrain system are
intended to be serviced as an assembly only. At-
tempting to remove or repair certain system sub-
components may result in personal injury and/or
improper system operation. Only those components
with approved repair and installation procedures in
the service manual should be serviced.
4.2.4 DRBIIITSAFETY INFORMATION
WARNING: EXCEEDING THE LIMITS OF THE
DRBIIITMULTIMETER IS DANGEROUS. IT
CAN EXPOSE YOU TO SERIOUS OR
POSSIBLY FATAL INJURY. CAREFULLY
READ AND UNDERSTAND THE CAUTIONS
AND SPECIFICATION LIMITS.
Follow the vehicle manufacturer 's service specifi-
cations at all times.
²Do not use the DRBIIItif it has been damaged.
²Do not use the test leads if the insulation is
damaged or if metal is exposed.
²To avoid electrical shock, do not touch the test
leads, tip or the circuit being tested.
²Choose the proper range and function for the
measurement. Do not try voltage or current mea-
surements that may exceed the rated capacity.
²Do not exceed the limits shown in the table below:
FUNCTION INPUT LIMIT
Volts 0-500 peak volts AC
0-500 volts DC
Ohms (Resistance)* 0-1.12 megohms
Frequency Measure
Frequency Generated0-10 kHz
Temperature -58 - +1100ÉF
-50 - +600ÉC
* Ohms cannot be measured if voltage is present.
Ohms can be measured only in a non-powered
circuit.
²Voltage between any terminal and ground must
not exceed 500v DC or 500v peak AC.
²Use caution when measuring voltage above 25v
DC or 25v AC.
²The circuit being tested must be protected by a 10
amp fuse or circuit breaker.
²Use the low current shunt to measure circuits up
to 10 amps. Use the high current shunt to mea-
sure circuits exceeding 10 amps.
²When testing for the presence of voltage or cur-
rent, make sure the meter is functioning cor-
rectly. Take a reading of a known voltage or
current before accepting a zero reading.
²When measuring current, connect the meter in
series with the load.
²Disconnect the live test lead before disconnecting
the common test lead.
7
GENERAL INFORMATION

Symptom:
P0514-BATTERY TEMP SENSOR CIRCUIT SIGNAL VOLTAGE TOO
HIGH
When Monitored and Set Condition:
P0514-BATTERY TEMP SENSOR CIRCUIT SIGNAL VOLTAGE TOO HIGH
When Monitored: With the ignition on.
Set Condition: The ECM detects Battery Temperature Sensor Signal voltage above 4.72
volts.
POSSIBLE CAUSES
INTERMITTENT CONDITION
BATTERY TEMPERATURE SENSOR GROUND CIRCUIT OPEN
BATTERY TEMPERATURE SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE
BATTERY TEMPERATURE SENSOR
BATTERY TEMPERATURE SENSOR SIGNAL CIRCUIT OPEN
ENGINE CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, monitor the Battery Temperature Sensor voltage.
Is the voltage above 4.5 volts?All
Ye s®Go To 2
No®Go To 6
2 Turn the ignition off.
Disconnect the Battery Temperature Sensor harness connector.
Turn the ignition on.
Measure the voltage on the Battery Temperature Sensor Signal circuit.
Is the voltage above 5.5 volts?All
Ye s®Repair the Battery Temperature Sensor Signal circuit for a short
to voltage.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 3
104
DRIVEABILITY - DIESEL

TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the Battery Temperature Sensor harness connector.
Connect a jumper wire between the Battery Temperature Sensor harness connector
cavities.
Turn the ignition on.
With the DRB, read the Battery Temperature Sensor voltage.
Is the voltage below 1.0 volt?All
Ye s®Replace the Battery Temperature Sensor in accordance with the
Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 4
4 Turn the ignition off.
Disconnect the Battery Temperature Sensor harness connector.
Connect a jumper wire between ground and the Battery Temperature Sensor Signal
circuit.
Turn the ignition on.
With the DRB, read the Battery Temperature Sensor voltage.
Is the voltage below 1.0 volt?All
Ye s®Repair the Sensor Ground circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 5
5 Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the Battery Temperature Sensor harness connector.
Measure the resistance of the Battery Temperature Sensor Signal circuit.
Is the resistance below 5.0 ohms?All
Ye s®Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No®Repair the Battery Temperature Sensor Signal circuit for an
open.
Perform ROAD TEST VERIFICATION - VER-2.
105
DRIVEABILITY - DIESEL
P0514-BATTERY TEMP SENSOR CIRCUIT SIGNAL VOLTAGE TOO HIGH
Ð
Continued

TEST ACTION APPLICABILITY
6WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help in identifying the intermittent condition.
With the engine running at normal operating temperature, monitor the DRB
parameters related to the DTC while wiggling the wiring harness. Look for param-
eter values to change and/or a DTC to set.
Review the DTC When Monitored and Set Conditions. If possible, try to duplicate the
conditions under which the DTC was set.
Refer to any Technical Service Bulletins (TSB) that may apply.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Were any of the above conditions present?All
Ye s®Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No®Test Complete.
106
DRIVEABILITY - DIESEL
P0514-BATTERY TEMP SENSOR CIRCUIT SIGNAL VOLTAGE TOO HIGH
Ð
Continued

Symptom:
P0560-SYSTEM VOLTAGE TOO HIGH
When Monitored and Set Condition:
P0560-SYSTEM VOLTAGE TOO HIGH
When Monitored: With the engine running.
Set Condition: The ECM detects battery voltage is above 17.5 volts.
POSSIBLE CAUSES
INTERMITTENT CONDITION
ECM - TARGET CHARGING VOLTAGE TOO LOW
GENERATOR FIELD DRIVER CIRCUIT SHORTED TO GROUND
GROUND CIRCUIT HIGH RESISTANCE
BATTERY SUPPLY CIRCUIT HIGH RESISTANCE
GENERATOR INTERNALLY SHORTED TO GROUND
ECM - FIELD DRIVER SHORTED TO GROUND
TEST ACTION APPLICABILITY
1NOTE: The battery must be fully charged and the generator belt must be in
good condition and tensioned properly before continuing.
Turn the ignition on.
With the DRB, actuate the Generator Field.
Measure the voltage between ground and the Generator Field Driver circuit by back
probing the Generator Field harness connector with a voltmeter.
Does the voltage cycle from B+ to below 2.0 volts?All
Ye s®Go To 2
No®Go To 6
NOTE: With the DRB, stop the Generator Field actuation.
2 Start the engine.
With the DRB, read the Target Charging voltage.
Is the Target Charging voltage above 13.0 volts?All
Ye s®Go To 3
No®Replace and program the Engine Control Module in accordance
with the Service Information.
Perform CHARGING VERIFICATION - VER-3.
11 7
DRIVEABILITY - DIESEL