TEST ACTION APPLICABILITY
2WARNING: 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.
3 Turn the ignition off.
Disconnect the Glow Plug Relay harness connector.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the ECM/PCM Relay Output
circuit.
Does the test light illuminate brightly?All
Ye s®Go To 4
No®Repair the ECM/PCM Relay Output circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
4 Turn the ignition off.
Install a substitute relay in place of the Glow Plug Relay.
Perform several ignition key cycles, pausing for at least 10 seconds between each
cycle.
Turn the ignition on.
With the DRB, read ECM DTCs.
Did this DTC reset?All
Ye s®Go To 5
No®Replace the Glow Plug Relay.
Perform ROAD TEST VERIFICATION - VER-2.
5 Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the Glow Plug Relay harness connector.
Remove the ECM/PCM Relay from the IPM.
Connect a jumper wire between cavity 1 and cavity 4 of the ECM/PCM Relay
connector.
Turn the ignition on.
Measure the voltage on the Glow Plug Relay Control circuit.
Is the voltage above 1.0 volt?All
Ye s®Repair the Glow Plug Relay Control circuit for a short to voltage.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 6
85
DRIVEABILITY - DIESEL
P0380-GLOW PLUG CIRCUIT A OPEN CIRCUIT ÐContinued
Symptom:
P0403-EGR SOLENOID CIRCUIT OPEN CIRCUIT
When Monitored and Set Condition:
P0403-EGR SOLENOID CIRCUIT OPEN CIRCUIT
When Monitored: With the ignition on.
Set Condition: The ECM detects an open or short to ground on the EGR Solenoid Control
circuit.
POSSIBLE CAUSES
INTERMITTENT CONDITION
ECM/PCM RELAY OUTPUT CIRCUIT OPEN
EGR SOLENOID CONTROL CIRCUIT SHORTED TO GROUND
EGR SOLENOID CONTROL CIRCUIT OPEN
SUBSTITUTE EGR SOLENOID
ENGINE CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, erase ECM DTCs.
Perform several ignition cycles, turning the ignition off for at least 10 seconds
between each ignition cycle.
Monitor the DRB for ECM DTCs.
Did this DTC reset?All
Ye s®Go To 2
No®Go To 7
2 Turn the ignition off.
Disconnect the EGR Solenoid harness connector.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the ECM/PCM Relay Output
circuit.
Does the test light illuminate brightly?All
Ye s®Go To 3
No®Repair the ECM/PCM Relay Output circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
87
DRIVEABILITY - DIESEL
TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the EGR Solenoid harness connector.
Disconnect the ECM harness connectors.
Measure the resistance between ground and the EGR Solenoid Control circuit.
Is the resistance above 100k ohms?All
Ye s®Go To 4
No®Repair the EGR Solenoid Control circuit for a short to ground.
Perform ROAD TEST VERIFICATION - VER-2.
4 Turn the ignition off.
Disconnect the EGR Solenoid harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the EGR Solenoid Control circuit.
Is the resistance below 5.0 ohms?All
Ye s®Go To 5
No®Repair the EGR Solenoid Control circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
5 Turn the ignition off.
Install a substitute EGR Solenoid in place of the vehicle's EGR Solenoid.
NOTE: Ensure the ECM and EGR Solenoid harness connectors are con-
nected.
Turn the ignition on.
With the DRB, check for this DTC to reset.
Did this DTC reset?All
Ye s®Go To 6
No®Replace the EGR Solenoid.
Perform ROAD TEST VERIFICATION - VER-2.
6 If there are no possible causes remaining, view repair. All
Repair
Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
88
DRIVEABILITY - DIESEL
P0403-EGR SOLENOID CIRCUIT OPEN CIRCUIT ÐContinued
TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the Radiator Fan Relay No. 1 harness connector.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the ECM/PCM Relay Output
circuit.
Did the test light illuminate brightly?All
Ye s®Go To 4
No®Repair the ECM/PCM Relay Output circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
4 Turn the ignition off.
Install a substitute relay in place of the Radiator Fan Relay No. 1.
Turn the ignition on.
With the DRB, actuate the Low Speed Fan Relay.
Do the Radiator Fans cycle on and off?All
Ye s®Replace Radiator Fan Relay No. 1.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 5
5 Turn the ignition off.
Disconnect the Radiator Fan Relay No. 1 harness connector.
Disconnect the ECM harness connectors.
Measure the resistance between ground and the Low Speed Radiator Fan Control
circuit.
Is the resistance below 100k ohms?All
Ye s®Repair the Low Speed Radiator Fan Control circuit for a short to
ground.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 6
6 Turn the ignition off.
Disconnect the Radiator Fan Relay No. 1 harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the Low Speed Radiator Fan Control circuit.
Is the resistance below 5.0 ohms?All
Ye s®Go To 7
No®Repair the Low Speed Radiator Fan Control circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
7 If there are no possible causes remaining, view repair. All
Repair
Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
93
DRIVEABILITY - DIESEL
P0480-FAN 1 CONTROL CIRCUIT OPEN CIRCUIT ÐContinued
TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the Radiator Fan Relay No. 2 harness connector.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the ECM/PCM Relay Output
circuit.
Did the test light illuminate brightly?All
Ye s®Go To 4
No®Repair the ECM/PCM Relay Output circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
4 Turn the ignition off.
One at a time, install a substitute relay in place of Radiator Fan Relays No. 2 and No.
3.
Turn the ignition on.
With the DRB, actuate the High Speed Fan Relay.
Does one Radiator Fan cycle on and off?All
Ye s®Replace the Radiator Fan Relay that the substitute relay caused
the radiator fan to cycle on and off.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 5
5 Turn the ignition off.
Disconnect the Radiator Fan Relays No. 2 and No. 3 harness connectors.
Disconnect the ECM harness connectors.
Measure the resistance between ground and the High Speed Radiator Fan Control
circuit.
Is the resistance above 100k ohms?All
Ye s®Go To 6
No®Repair the High Speed Radiator Fan Control circuit for a short to
ground.
Perform ROAD TEST VERIFICATION - VER-2.
6 Turn the ignition off.
Disconnect the Radiator Fan Relay No. 2 harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the High Speed Radiator Fan Control circuit.
Is the resistance below 5.0 ohms?All
Ye s®Go To 7
No®Repair the High Speed Radiator Fan Control circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
7 If there are no possible causes remaining, view repair. All
Repair
Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
97
DRIVEABILITY - DIESEL
P0481-FAN 2 CONTROL CIRCUIT OPEN CIRCUIT ÐContinued
TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the ECM harness connectors.
Using a 12-volt test light connected to 12-volts, check all of the ECM Ground circuits.
Does the test light illuminate brightly for each circuit?All
Ye s®Go To 4
No®Repair the Ground circuit(s) for high resistance.
Perform CHARGING VERIFICATION - VER-3.
4 Turn the ignition off.
Disconnect the ECM harness connectors.
Using a 12-volt test light connected to ground, check all of the ECM Battery Supply
circuits.
Does the test light illuminate brightly for each circuit?All
Ye s®Go To 5
No®Repair the Battery Supply circuit(s) for high resistance.
Perform CHARGING VERIFICATION - VER-3.
5WARNING: 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 CHARGING VERIFICATION - VER-3.
No®Test Complete.
6 Turn the ignition off.
Disconnect ECM harness connectors.
Disconnect the Generator Field harness connector.
Measure the resistance between ground and the Generator Field Driver circuit.
Is the resistance above 100k ohms?All
Ye s®Go To 7
No®Repair the Generator Field Driver circuit for a short to ground.
Perform CHARGING VERIFICATION - VER-3.
11 8
DRIVEABILITY - DIESEL
P0560-SYSTEM VOLTAGE TOO HIGH ÐContinued
Symptom List:
P0560-SYSTEM VOLTAGE TOO LOW
*CHECKING THE CHARGING SYSTEM OPERATION - DIESEL
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P0560-SYSTEM VOLTAGE TOO
LOW.
When Monitored and Set Condition:
P0560-SYSTEM VOLTAGE TOO LOW
When Monitored: With the engine running.
Set Condition: The ECM detects the system voltage at least 0.5 volt below the target
charging voltage for at least 3 seconds.
POSSIBLE CAUSES
CHECK FOR CYCLING VOLTAGE ON THE GENERATOR FIELD DRIVER CIRCUIT
INTERMITTENT CONDITION
GENERATOR BELT CONDITION OR TENSION
HIGH RESISTANCE IN THE FUEL HEATER RELAY OUTPUT CIRCUIT TO THE ECM
GENERATOR FIELD DRIVER CIRCUIT SHORTED TO VOLTAGE
GENERATOR FUSED B+ CIRCUIT HIGH RESISTANCE
ECM/PCM RELAY OUTPUT CIRCUIT OPEN
GENERATOR GROUND CIRCUIT HIGH RESISTANCE
GENERATOR FIELD DRIVER CIRCUIT OPEN
ENGINE CONTROL MODULE
TEST ACTION APPLICABILITY
1NOTE: If there are any Battery Sense DTCs (P1511 or P1512) present with
this DTC, diagnose the Battery Sense DTCs first.
NOTE: Inspect the vehicle for aftermarket accessories that may exceed the
Generator capacity.
NOTE: The battery must be fully charged before continuing.
Inspect the generator belt condition and tension.
Is the generator belt in good condition and tensioned properly?All
Ye s®Go To 2
No®Repair as necessary.
Perform CHARGING VERIFICATION - VER-3.
120
DRIVEABILITY - DIESEL
Symptom:
P0627-FUEL LIFT PUMP RELAY CONTROL CIRCUIT OPEN CIR-
CUIT
POSSIBLE CAUSES
INTERMITTENT CONDITION
IGNITION SWITCH (RUN/START) CIRCUIT OPEN
FUEL LIFT PUMP RELAY
FUEL LIFT PUMP RELAY CONTROL CIRCUIT SHORTED TO GROUND
FUEL LIFT PUMP RELAY CONTROL CIRCUIT OPEN
ENGINE CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, actuate the Fuel Lift Pump Relay.
Does the Fuel Lift Pump Relay cycle on and off?All
Ye s®Go To 2
No®Go To 3
2WARNING: 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.
3 Turn the ignition off.
Remove the Fuel Lift Pump Relay from the IPM.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the Ignition Switch (RUN/
START) circuit.
Did the test light illuminate brightly?All
Ye s®Go To 4
No®Repair the Ignition Switch (RUN/START) circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
129
DRIVEABILITY - DIESEL