
TEST ACTION APPLICABILITY
6 Refer to the appropriate Service Information and perform the Fuel Pressure Test.
NOTE: The following is a list of problems that can cause the fuel pressure to
become out of specification: restricted fuel filter or fuel lines, failed fuel
pressure solenoid, air in fuel system, failed fuel sending unit, gelled fuel,
faulty injector.
Is the fuel pressure within specification?All
Ye s®Replace the Fuel Pressure Sensor in accordance with the Service
Information.
No®Repair as necessary in accordance with the Service Information.
7WARNING: 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.
No®Test Complete.
157
DRIVEABILITY - DIESEL
P1130-FUEL RAIL PRESSURE MALFUNCTION LEAKAGE DETECTED Ð
Continued

TEST ACTION APPLICABILITY
5 Turn the ignition off.
Disconnect the Fuel Pressure Solenoid harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the Fuel Pressure Solenoid Control circuit.
Is the resistance below 5.0 ohms?All
Ye s®Go To 6
No®Repair the Fuel Pressure Solenoid Control circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
6 Turn the ignition off.
Disconnect the Fuel Pressure Solenoid harness connector.
Turn the ignition on.
With the DRB, erase ECM DTCs.
Monitor the DRB for ECM DTCs.
NOTE: The DRB should display P1131-FUEL PRESSURE SOLENOID OPEN
CIRCUIT.
Turn the ignition off.
Connect a jumper wire between cavity 1 and cavity 2 of the Fuel Pressure Solenoid
harness connector.
Turn the ignition on.
With the DRB, erase ECM DTCs.
Monitor the DRB for ECM DTCs.
NOTE: The DRB should display P1131-FUEL PRESSURE SOLENOID
SHORT CIRCUIT.
Does the DRB display the appropriate DTC for each condition?All
Ye s®Replace the Fuel Pressure Solenoid/Fuel Pump Assembly in
accordance with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 7
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.
160
DRIVEABILITY - DIESEL
P1131-FUEL PRESSURE SOLENOID OPEN CIRCUIT ÐContinued

TEST ACTION APPLICABILITY
8WARNING: 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.
161
DRIVEABILITY - DIESEL
P1131-FUEL PRESSURE SOLENOID OPEN CIRCUIT ÐContinued

TEST ACTION APPLICABILITY
4 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.
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 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.
163
DRIVEABILITY - DIESEL
P1511-BATTERY SENSE LINE 1 VOLTAGE TOO HIGH ÐContinued

TEST ACTION APPLICABILITY
4 Turn the ignition off.
Install a substitute relay in place of the Fuel Heater Relay.
Disconnect the ECM harness connectors.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the Fuel Heater Relay Output
circuit.
Is the test light on?All
Ye s®Replace the initial Fuel Heater Relay.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 5
5 Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the Crankcase Vent Heater harness connector.
Disconnect the Fuel Heater harness connector.
Remove the Fuel Heater Relay from the IPM.
Measure the resistance between ground and the Battery(+) Sense circuit.
Is the resistance above 100k ohms?All
Ye s®Go To 6
No®Repair the Battery(+) Sense circuit for a short to ground.
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.
7WARNING: 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.
165
DRIVEABILITY - DIESEL
P1511-BATTERY SENSE LINE 1 VOLTAGE TOO LOW ÐContinued

Symptom:
P1605-IGNITION SWITCH PLAUSIBILITY
When Monitored and Set Condition:
P1605-IGNITION SWITCH PLAUSIBILITY
When Monitored: With the ignition on.
Set Condition: The ECM detects a short to voltage on the Ignition Switch Sense circuit.
POSSIBLE CAUSES
INTERMITTENT CONDITION
ECM/PCM RELAY
ENGINE CONTROL MODULE
IGNITION SWITCH SENSE CIRCUIT SHORTED TO VOLTAGE
ECM/PCM RELAY OUTPUT CIRCUIT SHORTED TO VOLTAGE
ECM/PCM RELAY CONTROL CIRCUIT SHORTED TO GROUND
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, erase ECM DTCs.
Cycle the ignition switch on and off several times, pausing for at least 10 seconds at
each key off and key on.
Turn the ignition on.
With the DRB, read ECM DTCs.
Did this DTC reset?All
Ye s®Go To 2
No®Go To 6
2 Turn the ignition off.
Disconnect the ECM harness connectors.
Measure the voltage of all cavities in the ECM harness connectors.
Is the voltage above 2.0 volts on any of the cavities?All
Ye s®Go To 3
No®Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
3 Turn the ignition off.
Disconnect the ECM harness connectors.
Measure the voltage on ECM harness connector C1, cavity 22.
Is voltage present on ECM harness connector C1, cavity 22?All
Ye s®Go To 4
No®Repair the Ignition Switch Sense circuit that measured above 2.0
volts for a short to voltage.
Perform ROAD TEST VERIFICATION - VER-2.
166
DRIVEABILITY - DIESEL

TEST ACTION APPLICABILITY
4 Turn the ignition off.
Disconnect the ECM harness connectors.
Remove the ECM/PCM Relay from the IPM.
Turn the ignition on.
Measure the voltage on ECM harness connector C1 cavities 4 and 5.
Is the voltage below 2.0 volts on both circuits?All
Ye s®Go To 5
No®Repair the ECM/PCM Relay Output circuit for a short to voltage.
Perform ROAD TEST VERIFICATION - VER-2.
5 Turn the ignition off.
Disconnect the ECM harness connectors.
Remove the ECM/PCM Relay from the IPM.
Measure the resistance between ground and the ECM/PCM Relay Control circuit.
Is the resistance above 100k ohms?All
Ye s®Replace the ECM/PCM Relay.
Perform ROAD TEST VERIFICATION - VER-2.
No®Repair the ECM/PCM Relay Control circuit for a short to ground.
Perform ROAD TEST VERIFICATION - VER-2.
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.
167
DRIVEABILITY - DIESEL
P1605-IGNITION SWITCH PLAUSIBILITY ÐContinued

TEST ACTION APPLICABILITY
2 Turn the ignition on.
With the DRBIIIt, erase ECM DTCs.
Turn the ignition on and off several times pausing 10 seconds between each key cycle.
With the DRBIIIt, read the ECM DTCs.
Are any P1685 DTCs present?All
Ye s®Go To 3
No®Go To 4
3 Replace and program the SKIM in accordance with the Service Information.
Turn the ignition on.
With the DRBIIIt, erase ECM DTCs.
Turn the ignition on and off several times pausing for 10 seconds between key cycles.
With the DRBIIIt, read ECM DTCs.
Are there any P1685 DTC's present?All
Ye s®Replace and program the ECM in accordance with the Service
Information.
Perform ROAD TEST VERIFICATION - VER-2.
No®Test Complete.
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.
169
DRIVEABILITY - DIESEL
P1685-SKIM SYSTEM INVALID KEY CODE RECEIVED ÐContinued