TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the Intake Air Pressure Sensor and Engine Oil Sensor harness connec-
tors.
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 in Fuse Block No.1.
Turn the ignition on.
Measure the voltage at all circuits in the Engine Oil Sensor and Intake Air Pressure
Sensor harness connector cavities.
Is the voltage above 1.0 volt for any of the measurements?All
Ye s!Repair the circuit(s) that measured above 1.0 volt for a short to
voltage.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 4
4 Turn the ignition off.
Disconnect the Engine Oil Sensor harness connector.
Turn the ignition on.
With the DRBIIIt, erase ECM DTCs.
Turn the ignition off for 10 seconds. Turn the ignition on.
With the DRBIIIt, read ECM DTCs.
Does the DRB display this DTC?All
Ye s!Go To 5
No!Replace the Engine Oil Sensor.
Perform ROAD TEST VERIFICATION - VER-2.
5 Turn the ignition off.
Disconnect the Intake Air Pressure Sensor harness connector.
Turn the ignition on.
With the DRBIIIt, erase ECM DTCs.
Turn the ignition off for 10 seconds. Turn the ignition on.
With the DRBIIIt, read 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 ROAD TEST VERIFICATION - VER-2.
No!Replace the Intake Air Pressure Sensor.
Perform ROAD TEST VERIFICATION - VER-2.
207
DRIVEABILITY - DIESEL
P2332-SENSOR SUPPLY 3 VOLTAGE IS TOO HIGH ÐContinued
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 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.
208
DRIVEABILITY - DIESEL
P2332-SENSOR SUPPLY 3 VOLTAGE IS TOO HIGH ÐContinued
Symptom List:
P2333-S/C VEHICLE SPEED PLAUSIBILITY
P2338-S/C EXCESSIVE ACCELERATION
P2338-S/C EXCESSIVE DECELERATION
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P2333-S/C VEHICLE SPEED
PLAUSIBILITY.
POSSIBLE CAUSES
BRAKE SWITCH VERIFICATION
CAB DTCS
OPEN CAN BUS CIRCUITS
VERIFY CAB COMMUNICATION
WHEEL SPEED VERIFICATION
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 7
2 Turn the ignition on.
With the DRBIIItattempt to communicate with the CAB.
NOTE: If there are other DTCs set with this DTC, refer to the Symptom List
and repair other stored ECM DTCs before diagnosing this DTC.
Is the CAB communicating with the DRB?All
Ye s!Go To 3
No!Refer to the appropriate symptom in the Body Diagnostic Infor-
mation.
Perform ROAD TEST VERIFICATION - VER-2.
209
DRIVEABILITY - DIESEL
TEST ACTION APPLICABILITY
3 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 ROAD TEST VERIFICATION - VER-2.
No!Go To 4
4 Turn the ignition off.
Disconnect the CAB Module harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of each CAN Bus circuit between the ECM harness connector
and the CAB harness connector.
Is the resistance below 10.0 ohms for each measurement?All
Ye s!Go To 5
No!Repair the open CAN Bus circuit(s) between the ECM and the
SKREEM.
Perform ROAD TEST VERIFICATION - VER-2.
5 With the DRBIIIt, perform the Wheel Speed Test of the ABS system.
Were any problems found?All
Ye s!Repair wheel speed signal problem as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 6
6 Check the Brake Switch for proper operation and adjustment.
Were any problems found?All
Ye s!Adjust or replace the Brake Switch as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Test Complete.
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.
210
DRIVEABILITY - DIESEL
P2333-S/C VEHICLE SPEED PLAUSIBILITY ÐContinued
Symptom List:
P2339-ECM CHECKSUM ERROR #1
P2339-ECM CHECKSUM ERROR #2
P2339-ECM INVALID CODING
P2339-ECM INVALID DATA
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P2339-ECM CHECKSUM ERROR
#1.
POSSIBLE CAUSES
ENGINE CONTROL MODULE
TEST ACTION APPLICABILITY
1NOTE: This DTC indicates that an error occurred during ECM program-
ming.
Turn the ignition on.
With the DRBIIIt, erase ECM DTCs.
Refer to the Service Information and attempt to reprogram the ECM.
Perform several engine run cycles, turning the ignition off for at least 20 seconds
between each engine run cycle.
With the DRBIIIt, read the ECM DTCs.
Did this DTC set again?All
Ye s!Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No!Test Complete.
211
DRIVEABILITY - DIESEL
Symptom:
P2344-KICKDOWN SWITCH PLAUSIBILITY
POSSIBLE CAUSES
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.
NOTE: If there are any Accelerator Pedal Position Sensor DTC's present,
repair the APP Sensor DTC's before continuing.
Turn the ignition on.
With the DRB, erase ECM DTCs.
Turn the ignition off for 10 seconds.
Test drive the vehicle. Be sure to completely depress the accelerator pedal several
times to activate the Kickdown Switch.
Monitor the DRB for ECM DTCs.
Did this DTC set again?All
Ye s!Test Complete.
No!Go To 2
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.
212
DRIVEABILITY - DIESEL
Symptom List:
P2347-AUTOMATIC TRANSMISSION CODED AS MANUAL TRANS-
MISSION
P2347-CAN BUS CIRCUIT INTERUPTION
P2347-MANUAL TRANSMISSIO CODED AS AUTO TRANSMISSION
P2347-WRITE ERROR TO EEPROM
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P2347-AUTOMATIC TRANSMIS-
SION CODED AS MANUAL TRANSMISSION.
POSSIBLE CAUSES
ENGINE CONTROL MODULE
VERIFY ECM PROGRAMMING
TEST ACTION APPLICABILITY
1 Turn the Ignition on.
With the DRBIIIt, erase the ECM DTCs.
With the DRBIIIt, verify that the ECM is properly coded for the options and
components that the vehicle is equipped with.
NOTE: Reprogram the ECM with correct information if necessary.
Start and idle the engine.
With the DRBIIIt, read ECM DTCs.
Did this DTC set again?All
Ye s!Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No!Test complete.
Perform ROAD TEST VERIFICATION - VER-2.
213
DRIVEABILITY - DIESEL
Symptom:
P2351-ECM SUPPLY VOLTAGE TOO LOW
POSSIBLE CAUSES
ECM
ECM IGNITION CIRCUIT OPEN
STARTER OR LIFT PUMP RELAY CIRCUIT(S) SHORTED TO GROUND
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.
Turn the ignition on.
With the DRB, erase ECM DTCs.
Turn the ignition off for 10 seconds.
Test drive the vehicle.
Monitor the DRB for ECM DTCs.
Did this DTC set again?All
Ye s!Go To 2
No!Go To 4
2 Turn the ignition off.
Disconnect the ECM harness connectors.
Remove the Starter Relay and disconnect the Fuel Lift Pump harness connector
Measure the resistance between ground and the Starter Relay control circuit.
Measure the resistance between ground and the Fuel Lift Pump Relay control circuit.
Did both circuits measure above 1000 ohms?All
Ye s!Go To 3
No!Repair the relay control circuit(s) that did not measure above
1000 ohms for a short to ground.
Perform ROAD TEST VERIFICATION - VER-2.
3 Turn the ignition off.
Disconnect the ECM harness connectors.
Using the Service Wiring Information determine which circuits in the ECM harness
connector provide Ignition Switch power to the ECM.
Turn the ignition on.
Using a 12-volt test light connected to ground, check each Ignition Switch Output
circuits in the ECM harness connectors.
Does the test light illuminate brightly for each circuit?All
Ye s!Replace the ECM in accordance with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No!Repair the Ignition Supply circuit as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
214
DRIVEABILITY - DIESEL