
TEST ACTION APPLICABILITY
3 Turn the ignition off.
Install a substitute relay in place of the Fuel Lift Pump Relay.
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!Replace the Fuel Lift Pump Relay.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 4
4 Turn the ignition off.
Remove the Fuel Lift Pump Relay.
Disconnect the ECM harness connectors.
Measure the resistance between ground and the Fuel Lift Pump Relay Control
circuit.
Is the resistance above 1000 ohms?All
Ye s!Go To 5
No!Repair the Fuel Lift Pump Relay Control circuit for a short to
ground.
Perform ROAD TEST VERIFICATION - VER-2.
5 Turn the ignition off.
Remove the Fuel Lift Pump Relay.
Disconnect the ECM harness connectors.
Measure the resistance of the Fuel Lift Pump Relay Control circuit.
Is the resistance below 10.0 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 Fuel Lift Pump Relay Control circuit for an open.
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.
158
DRIVEABILITY - DIESEL
P2100-FUEL PUMP RELAY CIRCUIT OPEN CIRCUIT ÐContinued

Symptom List:
P2100-FUEL PUMP RELAY CIRCUIT SHORTED TO VOLTAGE
P2100-FUEL PUMP RELAY EXCESSIVE CURRENT
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P2100-FUEL PUMP RELAY
CIRCUIT SHORTED TO VOLTAGE.
POSSIBLE CAUSES
INTERMITTENT CONDITION
FUEL LIFT PUMP RELAY
FUEL LIFT PUMP RELAY CONTROL CIRCUIT SHORTED TO VOLTAGE
ENGINE CONTROL MODULE
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.
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.
159
DRIVEABILITY - DIESEL

TEST ACTION APPLICABILITY
7 Turn the ignition off.
Remove the Starter Relay.
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 Starter Relay Control circuit.
Is the voltage below 1.0 volt?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 Starter Relay Control circuit for a short to voltage.
Perform ROAD TEST VERIFICATION - VER-2.
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.
163
DRIVEABILITY - DIESEL
P2104-STARTER RELAY CIRCUIT SHORT CIRCUIT ÐContinued

TEST ACTION APPLICABILITY
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 ROAD TEST VERIFICATION - VER-2.
No!Test Complete.
166
DRIVEABILITY - DIESEL
P2110-BOOST PRESSURE SERVO MOTOR CIRCUIT SHORT CIRCUIT Ð
Continued

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.
170
DRIVEABILITY - DIESEL
P2111-BOOST PRESSURE SERVO MOTOR CIRCUIT SHORT TO
GROUND Ð
Continued

TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the Glow Plug Control Module harness connector.
Using a 12-volt test light connected to ground, check the Battery Supply circuit at the
Glow Plug Control Module harness connector.
Does the test light illuminate brightly?All
Ye s!Replace the Glow Plug Control Module.
Perform ROAD TEST VERIFICATION - VER-2.
No!Repair the Glow Plug Control Module Battery Supply circuit for
an open.
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.
172
DRIVEABILITY - DIESEL
P2132-GLOW PLUG CONTROL MODULE CIRCUIT OPEN CIRCUIT Ð
Continued

TEST ACTION APPLICABILITY
7 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 P2500-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 P2501-FUEL PRESSURE SOLENOID
SHORT CIRCUIT.
Does the DRB display the appropriate DTC for each condition?All
Ye s!Replace the Fuel Pressure Solenoid 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.
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.
176
DRIVEABILITY - DIESEL
P2151-FUEL PRESS SOLENOID SIGNAL PLAUSIBILITY HIGH Ð
Continued

TEST ACTION APPLICABILITY
6 Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the Fuel Quantity Solenoid harness connector.
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 each of the Fuel Quantity Solenoid circuits.
Is the voltage below 1.0 volt for each measurement?All
Ye s!Replace the Fuel Quantity Solenoid in accordance with the
Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No!Repair the circuit(s) that measured above 1.0 volts for a short to
voltage.
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 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.
179
DRIVEABILITY - DIESEL
P2197-FUEL QUANTITY SOLENOID OPEN CIRCUIT ÐContinued