
TEST ACTION APPLICABILITY
2NOTE: If DTC P1611, P2306 or P2332 is present with this DTC, diagnose
DTCs P1611, P2306 or P2332 before diagnosing this DTC.
NOTE: Check the ECM for other ECM DTC's related to circuits that are
open, shorted to ground or low voltage problems.
Does the DRB also display these type of DTC's?All
Ye s!Go To 3
No!Go To 4
3 Turn the ignition off.
Disconnect the ECM harness connectors.
Turn the ignition on.
Connect a jumper wire between ground and the Engine Control Relay Signal circuit
in ECM C2 harness connector cavity 44.
Using a 12-volt test light connected to ground, check the Fused Engine Control Relay
Output circuits at the ECM C2 harness connector cavities 1, 3 and 5.
Does the test light illuminate brightly for each circuit?All
Ye s!Go To 4
No!Refer to symptom list and perform Checking the ECM Power and
Grounds.
Perform ROAD TEST VERIFICATION - VER-2.
4 Turn the ignition off.
Install a substitute relay in place of the Starter Relay.
Turn the ignition on.
With the DRBIIIt, erase DTCs.
Attempt to start the engine several times, pausing for at least 10 seconds between
each cycle.
Turn the ignition on.
With the DRB, read ECM DTCs.
Did this DTC set again?All
Ye s!Go To 5
No!Replace the Starter Relay.
Perform ROAD TEST VERIFICATION - VER-2.
5 Turn the ignition off.
Remove the Starter Relay.
Disconnect the ECM harness connectors.
Measure the resistance of the Starter Relay Control circuit.
Is the resistance below 10.0 ohms?All
Ye s!Go To 6
No!Repair the Starter Relay Control circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
6 Turn the ignition off.
Remove the Starter Relay.
Disconnect the ECM harness connectors.
Measure the resistance between ground and the Starter Relay Control circuit.
Is the resistance above 1000 ohms?All
Ye s!Go To 7
No!Repair the Starter Relay Control circuit for a short to ground.
Perform ROAD TEST VERIFICATION - VER-2.
162
DRIVEABILITY - DIESEL
P2104-STARTER RELAY CIRCUIT SHORT CIRCUIT ÐContinued

Symptom List:
P2110-BOOST PRESSURE SERVO MOTOR CIRCUIT SHORT CIR-
CUIT
P2112-BOOST PRESSURE SERVO MOTOR CIRCUIT EXCESSIVE
CURRENT
P2526-BOOST PRESSURE SERVO MOTOR SHORT TO VOLTAGE
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P2110-BOOST PRESSURE
SERVO MOTOR CIRCUIT SHORT CIRCUIT.
When Monitored and Set Condition:
P2110-BOOST PRESSURE SERVO MOTOR CIRCUIT SHORT CIRCUIT
When Monitored: With the ignition on.
Set Condition: The ECM detects a short to battery on the Boost Pressure Servo Motor
Control circuit.
POSSIBLE CAUSES
INTERMITTENT CONDITION
BOOST PRESSURE SERVO MOTOR
BOOST PRESSURE SERVO MOTOR CONTROL SHORT TO VOLTAGE
ENGINE CONTROL MODULE - INTERNAL
ENGINE CONTROL MODULE - INTERNAL SHORT TO VOLTAGE
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.
Turn the ignition on.
With the DRB, erase ECM DTCs.
Test drive the vehicle and monitor the DRB for ECM DTCs.
Did this DTC set again?All
Ye s!Go To 2
No!Go To 5
164
DRIVEABILITY - DIESEL

TEST ACTION APPLICABILITY
2 Turn the ignition off.
Disconnect the Boost Pressure Servo Motor harness connector.
Turn the ignition on.
With the DRB, erase ECM DTCs.
Monitor the DRB for ECM DTCs.
Does the DRB display BOOST PRESSURE SERVO MOTOR OPEN CIRCUIT?All
Ye s!Replace the Boost Pressure Servo Motor.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 3
3 Turn the ignition off.
Disconnect the Boost Pressure Servo Motor harness connector.
Turn the ignition on.
Measure the voltage of the Boost Pressure Servo Motor Control circuit.
Is the voltage below 0.5 volt?All
Ye s!Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 4
4 Turn the ignition off.
Disconnect the Boost Pressure Servo Motor 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 Boost Pressure Servo Motor Control circuit.
Is the voltage below 0.5 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 Boost Pressure Servo Motor Control circuit for a short
to voltage.
Perform ROAD TEST VERIFICATION - VER-2.
165
DRIVEABILITY - DIESEL
P2110-BOOST PRESSURE SERVO MOTOR CIRCUIT SHORT CIRCUIT Ð
Continued

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.
Turn the ignition on.
With the DRB, erase ECM DTCs.
Test drive the vehicle.
Monitor the DRB for ECM DTCs.
Did this DTC set again?All
Ye s!Go To 2
No!Go To 8
2NOTE: Check the ECM for other ECM DTC's related to circuits that are
open, shorted to ground or low voltage problems.
Does the DRB also display these type of DTC's?All
Ye s!Go To 3
No!Go To 4
3 Turn the ignition off.
Disconnect the ECM harness connectors.
Connect a jumper wire between ground and the Engine Control Relay Signal circuit
in ECM C2 harness connector cavity 44.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the Fused Engine Control Relay
Output circuits at the ECM C1 harness connector cavities 1, 3 and 5.
Does the test light illuminate brightly for each circuit?All
Ye s!Go To 4
No!Refer to symptom list and perform Checking the ECM Power and
Grounds.
Perform ROAD TEST VERIFICATION - VER-2.
4 Turn the ignition off.
Disconnect the Boost Pressure Servo Motor harness connector.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the 12 Volt Supply circuit in the
Boost Pressure Servo Motor harness connector.
Does the test light illuminate brightly?All
Ye s!Go To 5
No!Repair the 12 Volt Supply circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
168
DRIVEABILITY - DIESEL
P2111-BOOST PRESSURE SERVO MOTOR CIRCUIT SHORT TO
GROUND Ð
Continued

Symptom List:
P2132-GLOW PLUG CONTROL MODULE CIRCUIT OPEN CIRCUIT
P2132-GLOW PLUG CONTROL MODULE CIRCUIT SHORTED TO
GROUND
P2132-GLOW PLUG CONTROL MODULE CIRCUIT SHORTED TO
VOLTAGE OR OPEN
P2132-GLOW PLUG CONTROL MODULE FAULT
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P2132-GLOW PLUG CONTROL
MODULE CIRCUIT OPEN CIRCUIT.
POSSIBLE CAUSES
BATTERY SUPPLY CIRCUIT OPEN
GROUND CIRCUIT OPEN
INTERMITTENT CONDITION
GLOW PLUG 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, erase ECM DTCs.
Turn the ignition off for 10 seconds.
Turn the ignition on.
Monitor the DRB for ECM DTCs.
Repeat this test several times.
Did this DTC set again?All
Ye s!Go To 2
No!Go To 4
2 Turn the ignition off.
Disconnect the Glow Plug Control Module harness connector.
Using a 12-volt test light connected to 12-volts, check the Ground circuit at the Glow
Plug Control Module harness connector.
Does the test light illuminate brightly?All
Ye s!Go To 3
No!Repair the Glow Plug Control Module Ground circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
171
DRIVEABILITY - DIESEL

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.
WARNING: HIGH-PRESSURE FUEL LINES DELIVER DIESEL FUEL UN-
DER EXTREME PRESSURE FROM THE INJECTION PUMP TO THE FUEL
INJECTORS. THIS MAY BE AS HIGH AS 23,200 PSI (1600 BAR). USE
EXTREME CAUTION WHEN INSPECTING FOR HIGH-PRESSURE FUEL
LEAKS.
WARNING: FUEL UNDER THIS AMOUNT OF PRESSURE CAN PENE-
TRATE SKIN CAUSING PERSONAL INJURY OR DEATH. INSPECT FOR
HIGH-PRESSURE FUEL LEAKS WITH A SHEET OF CARDBOARD. WEAR
SAFETY GOGGLES AND ADEQUATE PROTECTIVE CLOTHING WHEN
SERVICING FUEL SYSTEM.
Turn the ignition on.
With the DRB, erase ECM DTCs.
Start the engine several times, turning the ignition off for at least 30 seconds
between each run cycle.
Monitor the DRB for ECM DTCs.
Did this DTC set again?All
Ye s!Go To 2
No!Go To 8
2NOTE: Check the ECM for other ECM DTC's related to circuits that are
open, shorted to ground or low voltage problems.
Does the DRB also display these type of DTC's?All
Ye s!Go To 3
No!Go To 4
3 Turn the ignition off.
Disconnect the ECM harness connectors.
Turn the ignition on.
Connect a jumper wire between ground and the Engine Control Relay Signal circuit
in ECM C2 harness connector cavity 44.
Using a 12-volt test light connected to ground, check the Fused Engine Control Relay
Output circuits at the ECM C1 harness connector cavities 1, 3 and 5.
Does the test light illuminate brightly for each circuit?All
Ye s!Go To 4
No!Refer to symptom list and perform Checking the ECM Power and
Grounds.
Perform ROAD TEST VERIFICATION - VER-2.
174
DRIVEABILITY - DIESEL
P2151-FUEL PRESS SOLENOID SIGNAL PLAUSIBILITY HIGH 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
2 Turn the ignition on.
With the DRBIIIt, read the CAB DTCs.
Are there any CAB DTCs?All
Ye s!Refer to symptom list for problems related to CAB.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 3
3NOTE: 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 DRBIIIt, erase the ECM DTCs.
Turn the ignition off then turn the ignition on and wait 60 seconds.
With the DRBIIIt, read the ECM DTCs.
Does the DRB display this DTC?All
Ye s!Replace and program the Engine Control Module in accordance
with the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 4
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 BODY VERIFICATION TEST - VER 1.
No!Test Complete.
181
DRIVEABILITY - DIESEL
P2203-TORQUE REDUCTION MESSAGE FROM ABS - CAN PLAUSIBIL-
ITY Ð
Continued