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 and 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.
59
DRIVEABILITY - DIESEL
P0190-FUEL PRESS SENSOR CIRCUIT MALF SIGNAL VOLTAGE TOO
LOW Ð
Continued
POSSIBLE CAUSES
CORRECTION QUANTITY CHECK
CYLINDER SPEED CHECK
ENGINE COMPRESSION
INJECTOR LEAKAGE
INTERMITTENT CONDITION
TEST ACTION APPLICABILITY
1NOTE: If the ECM detects and stores a DTC, the ECM also stores the
engine/vehicle operating conditions under which the DTC was set. Some of
these conditions are displayed on the DRB at the same time the DTC is
displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to
duplicate these conditions may assist when checking for an active DTC.
With the DRBIIIt, erase ECM DTCs.
Test drive the vehicle and attempt to duplicate the problem.
With the DRB, read ECM DTC's.
Did this DTC set again?All
Ye s!Go To 2
No!Go To 8
2 Start and idle the engine for 5 minutes.
Turn the ignition off.
Inspect the fuel rail, fuel pressure sensor, fuel pressure solenoid and all fuel injectors
for evidence of fuel leakage.
Is there fuel leakage near any of the injectors or the fuel rail?All
Ye s!Refer to the Service Information to repair fuel leakage.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 3
3 Turn the ignition off.
With the DRBIIIt, perform the Cylinder Compression Test.
Is the cylinder compression within specification for all cylinders?All
Ye s!Go To 4
No!Repair as necessary in accordance with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
4 Turn the ignition off.
Read and note the six-digit code located on the top of each injector.
Turn the ignition on.
With the DRBIIIt, check the current programmed injector classifications to the
six-digit codes from the vehicles current fuel injectors.
Are all of the Fuel Injectors classified correctly?All
Ye s!Go To 5
No!Using the DRB III, reset injectors to correct classification.
Perform ROAD TEST VERIFICATION - VER-2.
67
DRIVEABILITY - DIESEL
P0300-MISFIRE DETECTED ÐContinued
Symptom:
P0500-WHEEL SPEED SENSOR PLAUS - CAN BUS MESSAGE FROM
ABS
When Monitored and Set Condition:
P0500-WHEEL SPEED SENSOR PLAUS - CAN BUS MESSAGE FROM ABS
When Monitored: With the ignition on.
Set Condition: The Boost Pressure Sensor Signal voltage exceeds 4.85 volts for at least 2
seconds.
POSSIBLE CAUSES
INTERMITTENT CONDITION
CHECK FOR RELATED CONTROLLER ANTILOCK BRAKES DTCS
CHECK FOR RELATED TRANSMISSION CONTROL MODULE DTCS
ENGINE CONTROL MODULE
TEST ACTION APPLICABILITY
1NOTE: If the ECM displays multiple CAN Bus related DTC's, check the CAN
Bus circuits at the ECM harness connector for proper connection before
continuing with this test.
NOTE: If the ECM detects and stores a DTC, the ECM also stores the
engine/vehicle operating conditions under which the DTC was set. Some of
these conditions are displayed on the DRB at the same time the DTC is
displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to
duplicate these conditions may assist when checking for an active DTC.
Turn the ignition on.
With the DRB, erase ECM DTCs.
Test drive the vehicle.
With the DRB, read the ECM DTC's.
Does the DRB display this DTC?All
Ye s!Go To 2
No!Go To 4
2 Turn the ignition on.
With the DRB, check for Controller Antilock Brakes DTCs.
NOTE: The ECM Receives vehicle speed messages via CAB Bus from the ABS
module. An interruption on the CAN Bus can cause this fault to set.
Are any related CAB DTCs present?All
Ye s!Refer to symptom list for problems related to CAB DTCs before
continuing.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 3
69
DRIVEABILITY - DIESEL
TEST ACTION APPLICABILITY
3NOTE: The TCM Receives vehicle speed messages via CAB Bus from the ABS
module. An interruption on the CAN Bus can cause this fault to set.
Turn the ignition on.
With the DRB, check the TCM for DTCs.
Are any ABS CAN Bus Message or Vehicle Speed related TCM DTCs present?All
Ye s!Replace the CAB in accordance with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No!Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
4WARNING: 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.
70
DRIVEABILITY - DIESEL
P0500-WHEEL SPEED SENSOR PLAUS - CAN BUS MESSAGE FROM ABS
Ð
Continued
Symptom List:
P1222-ACC PEDAL POSITION SENSOR 1 CKT PLAUSIBILITY
P1222-ACC PEDAL POSITION SENSOR 1 CKT SIGNAL VOLTAGE
TOO HIGH
P1222-ACC PEDAL POSITION SENSOR 1 CKT SIGNAL VOLTAGE
TOO LOW
P1234-ACC PEDAL POSITION SENSOR 2 CIRCUIT PLAUSIBILITY
P1234-ACC PEDAL POSITION SENSOR 2 CKT SIGNAL VOLTAGE
TOO HIGH
P1234-ACC PEDAL POSITION SENSOR 2 CKT SIGNAL VOLTAGE
TOO LOW
P2327-APP SENSOR PLAUSIBILITY
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P1222-ACC PEDAL POSITION
SENSOR 1 CKT PLAUSIBILITY.
POSSIBLE CAUSES
ACCELERATOR PEDAL POSITION SENSOR
ECM - APP SENSOR 1 5-VOLT SUPPLY CIRCUIT
SENSOR GROUND OPEN (APP SENSOR)
INTERMITTENT CONDITION
APP SENSOR 5-VOLT SUPPLY CIRCUIT OPEN
APP SENSOR SIGNAL CIRCUIT OPEN
APP SENSOR 5-VOLT SUPPLY CIRCUIT SHORTED TO SENSOR GROUND
APP SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
APP SENSOR 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
VERIFY APP SENSOR OPERATION
APP SENSOR SIGNAL CIRCUIT SHORTED TO THE SENSOR GROUND CIRCUIT
APP SENSOR 5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
ECM - SENSOR GROUND OPEN
APP SENSOR CIRCUIT SHORTED TO VOLTAGE
APP SENSOR GROUND CIRCUIT SHORTED TO VOLTAGE
ECM - APP SENSOR SIGNAL CIRCUIT
73
DRIVEABILITY - DIESEL
TEST ACTION APPLICABILITY
1NOTE: If DTC P1611, P2306 or P2332 is present with this DTC, diagnose
DTCs P1611, P2306 or P2332 before diagnosing this DTC.
NOTE: If the ECM detects and stores a DTC, the ECM also stores the
engine/vehicle operating conditions under which the DTC was set. Some of
these conditions are displayed on the DRB at the same time the DTC is
displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to
duplicate these conditions may assist when checking for an active DTC.
NOTE: The APP Sensor is a device that contains 2 separate potentiometer
type sensors. Each sensor has its own 5-volt supply circuit, sensor ground
circuit and signal circuit. The APP Sensor no longer incorporates a low-idle
switch.
NOTE: The APP Sensor 2 signal should always be approximately 1/2 the
voltage of the APP Sensor 1 signal.
Turn the ignition on.
Using a voltmeter, backprobe the APP Sensor 1 and APP Sensor 2 Signal circuits at
the APP Sensor harness connector with the accelerator pedal in the at rest position.
Is the voltage between 0.28 and 0.37 volt for sensor 1 and 0.10 and 0.19 volt for sensor
2?All
Ye s!Go To 2
No!Go To 5
2 Turn the ignition on.
Fully depress the accelerator pedal.
Using a voltmeter backprobe the APP Sensor harness connector and read the voltage
for APP Sensor 1 and APP Sensor 2 Signal circuits.
Is the voltage between 4.45 and 4.75 volts for #1 and 2.15 and 2.45 volts for #2?All
Ye s!Go To 3
No!Go To 5
3 Turn the ignition on.
With the DRB, read the APP Sensor 1 and APP Sensor 2 percentages (%).
With the accelerator pedal in the idle position, slowly depress the accelerator pedal
until the pedal is fully depressed.
NOTE: The percentage readings for APP Sensors 1 and 2 should increase
smoothly as the pedal is depressed.
NOTE: This test can also performed using a voltmeter by back probing each
APP Sensor Signal circuit at the APP Sensor harness connector and
observing the voltmeter for a smooth voltage change through the entire
pedal travel.
Does the percentage (voltage) increase smoothly for both readings with the acceler-
ator pedal travel?All
Ye s!Go To 4
No!Replace the Accelerator Pedal Position Sensor in accordance with
the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
74
DRIVEABILITY - DIESEL
P1222-ACC PEDAL POSITION SENSOR 1 CKT PLAUSIBILITY ÐContinued
TEST ACTION APPLICABILITY
4WARNING: 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 and 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 by slowly pressing and releasing the
accelerator pedal several times.
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.
5NOTE: Perform the rest of this diagnostic procedure on the individual APP
Sensor Potentiometer (1 or 2) that did not display the correct voltages in the
previous test.
Turn the ignition off.
Disconnect the APP Sensor harness connector.
Turn the ignition on.
Measure the voltage of the 5-Volt Supply circuit in the APP Sensor harness connector.
Is the voltage between 4.7 and 5.3 volts?All
Ye s!Go To 6
No!Go To 14
6 Turn the ignition off.
Disconnect the APP Sensor harness connector.
Connect a jumper wire between APP Sensor Signal circuit and the 5-volt supply
circuit at the APP Sensor harness connector .
With the DRB, read the PEDAL OUTPUT VOLTS.
Does the DRB display between 4.0 and 5.5 volts?All
Ye s!Go To 7
No!Go To 10
7 Turn the ignition off.
Disconnect the APP Sensor harness connector.
Disconnect the ECM harness connectors.
Remove the Engine Control Relay.
Connect a jumper wire between cavity 30 and cavity 87 of the Engine Control Relay
connector.
Turn the ignition on.
Measure the voltage of the APP Sensor Ground circuit.
Is the voltage above 1.0 volt?All
Ye s!Repair the App Sensor Ground circuit for a short to voltage.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 8
75
DRIVEABILITY - DIESEL
P1222-ACC PEDAL POSITION SENSOR 1 CKT PLAUSIBILITY ÐContinued
TEST ACTION APPLICABILITY
8 Turn the ignition off.
Disconnect the APP Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the Sensor Ground circuit between the APP Sensor and the
ECM.
Is the resistance below 10.0 ohms?All
Ye s!Go To 9
No!Repair the APP Sensor Ground circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
9 Turn the ignition off.
Disconnect the APP Sensor harness connector.
Using a 12-volt test light connected to 12-volts, check the Sensor Ground circuit of
the appropriate potentiometer.
Does the test light illuminate brightly?All
Ye s!Replace the Accelerator Pedal Position Sensor.
Perform ROAD TEST VERIFICATION - VER-2.
No!Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
10 Turn the ignition off.
Disconnect the APP Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the APP Sensor Signal circuit.
Is the resistance below 10.0 ohms?All
Ye s!Go To 11
No!Repair the APP Sensor Signal circuit for an open
Perform ROAD TEST VERIFICATION - VER-2.
11 Turn the ignition off.
Disconnect the APP Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance between ground and the APP Sensor Signal circuit.
Is the resistance below 1000 ohms?All
Ye s!Repair the APP Sensor Signal circuit for a short to ground.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 12
12 Turn the ignition off.
Disconnect the APP Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance between the APP Sensor Signal circuit and the Sensor
Ground circuit at the APP Sensor harness connector.
Is the resistance below 1000 ohms?All
Ye s!Repair the APP Sensor Signal and Sensor Ground circuits for a
short together.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 13
76
DRIVEABILITY - DIESEL
P1222-ACC PEDAL POSITION SENSOR 1 CKT PLAUSIBILITY ÐContinued