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
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 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.
Disconnect the EGR Valve harness connector.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the Engine Control Relay
Output circuit in the EGR Valve harness connector.
Does the test light illuminate brightly?All
Ye s!Go To 5
No!Repair the Engine Control Relay Output circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
5 Turn the ignition off.
Disconnect the EGR Valve harness connector.
Disconnect the ECM harness connectors.
Measure the resistance between the EGR Valve Control circuit in the EGR Valve
harness connector and ground.
Is the resistance above 1000 ohms?All
Ye s!Go To 6
No!Repair the EGR Valve Control circuit for a short to ground.
Perform ROAD TEST VERIFICATION - VER-2.
6 Turn the ignition off.
Disconnect the EGR Valve harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the EGR Valve Control circuit.
Is the resistance below 10.0 ohms?All
Ye s!Go To 7
No!Repair the EGR Valve Control circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
219
DRIVEABILITY - DIESEL
P2511-EGR VALVE SIGNAL CIRCUIT SHORTED TO GROUND ÐContinued
TEST ACTION APPLICABILITY
2 Turn the ignition off.
Disconnect the ECM harness connectors.
Connect a jumper wire between ground and the Engine Control Relay Control 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 C2 harness connector cavities 1, 3 and 5.
Choose the appropriate result.All
Test light is on for all circuits.
Go To 3
Test light is on for 1 or 2 circuits
Repair the Engine Control Relay Output circuit(s) that did not
illuminate brightly for an open.
Perform ROAD TEST VERIFICATION - VER-2.
Light off for all circuits.
Refer to symptom Checking the ECM Power and Grounds.
Perform ROAD TEST VERIFICATION - VER-2.
3 Turn the ignition off.
Disconnect the Crankcase Vent Heater harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the both circuits between the Crankcase Vent Heater
harness connector and the ECM harness connector.
Is the resistance below 10.0 ohms for each measurement?All
Ye s!Go To 4
No!Repair the Crankcase Vent Heater circuit(s) for an open.
Perform ROAD TEST VERIFICATION - VER-2.
4 Turn the ignition off.
Disconnect the Crankcase Vent Heater harness connector.
Disconnect the ECM harness connectors.
Measure the resistance between ground and both of the Crankcase Vent Heater
circuits.
Is the resistance above 1000 ohms for each circuit?All
Ye s!Go To 5
No!Repair the Crankcase Vent Heater circuit(s) for a short to ground.
Perform ROAD TEST VERIFICATION - VER-2.
5 Turn the ignition off.
Disconnect the Crankcase Vent Heater harness connector.
Disconnect the ECM harness connectors.
Turn the ignition on.
Measure the voltage of the both Crankcase Vent Heater circuits.
Is the voltage below 1.0 volt for each circuit?All
Ye s!Go To 6
No!Repair the Crankcase Vent Heater circuit for a short to voltage.
Perform ROAD TEST VERIFICATION - VER-2.
222
DRIVEABILITY - DIESEL
P2514-CRANKCASE VENT HEATER OPEN CIRCUIT ÐContinued
Symptom:
*CHECKING THE POWER AND GROUNDS
POSSIBLE CAUSES
CHECKING THE ENGINE CONTROL RELAY SYSTEM
EC RELAY OUTPUT CIRCUIT
ECM GROUND CIRCUIT(S) OPEN
ECM OUTPUT SHORTED - FUSE 16
ENGINE CONTROL MODULE
ENGINE CONTROL RELAY
ENGINE CONTROL RELAY B+ SUPPLY
ENGINE CONTROL RELAY CONTROL CIRCUIT OPEN
ENGINE CONTROL RELAY CONTROL CIRCUIT SHORT TO VOLTAGE
ENGINE CONTROL RELAY OUTPUT CIRCUIT(S) OPEN
ENGINE CONTROL RELAY OUTPUT CKT SHORTED TO GROUND FUSE #16
ENGINE CONTROL RELAY OUTPUT CKT SHORTED TO GROUND FUSE #17
IGNITION SWITCH START OUTPUT CIRCUIT OPEN
IGNITION SWITCH START/RUN OUTPUT CIRCUIT OPEN
SHORTED COMPONENT
TEST ACTION APPLICABILITY
1 Turn the ignition off.
Disconnect the ECM harness connectors.
Using a 12-volt test light connected to 12-volts, check each of the ECM ground
circuits in ECM harness connector C2 cavities 2, 4 and 6.
Did the test light illuminate brightly for each cavity?All
Ye s!Go To 2
No!Repair the ECM Ground circuit(s) for an open.
Perform ROAD TEST VERIFICATION - VER-2.
2 Turn the ignition off.
Disconnect the ECM harness connectors.
Turn the ignition switch to the Start position.
Using a 12-volt test light connected to ground, check the Fused Ignition Switch Start
Output circuit in ECM C2 harness connector cavity 36.
Does the test light illuminate brightly?All
Ye s!Go To 3
No!Repair the Ignition Switch Start Output circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
235
DRIVEABILITY - DIESEL
TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the ECM harness connectors.
Turn the ignition switch to the Start position.
Using a 12-volt test light connected to ground, check the Fused Ignition Switch
Start/Run Output circuit in ECM C2 harness connector cavity 19.
Repeat the previous step with the ignition switch in the Run position.
Does the test light illuminate brightly in the Start and Run positions?All
Ye s!Go To 4
No!Repair the Ignition Switch Start/Run Output circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
4 Turn the ignition off.
Remove the Engine Control Relay from Fuse Block No. 1.
Using a 12-volt test light connected to 12-volts, check the Engine Control Relay
Control circuit in the Engine Control Relay connector in Fuse Block No. 1.
Turn the ignition on.
Does the test light illuminate?All
Ye s!Go To 5
No!Go To 14
5 Turn the ignition off.
Remove and inspect Fuse #17 from Fuse Block No.1.
Is the fuse open?All
Ye s!Go To 6
No!Go To 8
6 Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the EGR Valve harness connector.
Disconnect the Boost Pressure Solenoid harness connector.
Remove the Starter Relay.
Remove the Lift Pump Relay.
Install a good fuse in place of Fuse #17 in Fuse Block No.1
Connect a jumper wire between ground and the Engine Control Relay Control circuit
in ECM C2 harness connector cavity 44.
Turn the ignition on.
Remove and inspect Fuse #17 in Fuse Block No. 1.
Is the fuse open?All
Ye s!Repair the Engine Control relay Output circuit for a short to
ground.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 7
7NOTE: A short circuit exists in one of the following: Lift Pump Relay, Starter
Relay, EGR Valve, Boost Pressure Servo Motor or ECM.
View repair.All
Ye s!Using the Service Information wiring check the listed components
for short circuits. Replace the shorted component as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
236
DRIVEABILITY - DIESEL
*CHECKING THE POWER AND GROUNDS ÐContinued
TEST ACTION APPLICABILITY
8 Turn the ignition off.
Remove and inspect Fuse #16 from Fuse Block No.1
Is the fuse open?All
Ye s!Go To 9
No!Go To 11
9 Turn the ignition off.
Disconnect the ECM harness connectors.
Install a good fuse in place of Fuse #16 in Fuse Block No.1
Connect a jumper wire between ground and the Engine Control Relay Control circuit
in ECM C2 harness connector cavity 44.
Remove and inspect Fuse #16 from Fuse Block No.1.
Is the fuse open?All
Ye s!Repair the Engine Control Relay Output circuit for a short to
ground.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 10
10 The Fuel Injectors, Crankcase Heater, Water In Fuel Sensor and related circuits can
cause Fuse #16 in Fuse Block No.1 to open. Use the Service Information Wiring
Diagrams and check these circuits/components for shorted circuits.
Were any problems found.All
Ye s!Repair or replace shorted circuit/component as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Replace and program the ECM in accordance with the Service
Information.
Perform ROAD TEST VERIFICATION - VER-2.
11 Turn the ignition off.
Disconnect the ECM harness connectors.
Connect a jumper wire between ground and the Engine Control Relay Control 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 C2 harness connector cavities 1, 3 and 5.
Choose the appropriate result.All
Test light is on for all circuits.
Test Complete.
Test light is on for 1 or 2 circuits
Repair the Engine Control Relay Output circuit(s) for an open.
Perform ROAD TEST VERIFICATION - VER-2.
Light off for all circuits.
Go To 12
237
DRIVEABILITY - DIESEL
*CHECKING THE POWER AND GROUNDS ÐContinued
TEST ACTION APPLICABILITY
12 Turn the ignition off.
Substitute the Engine Control Relay with a known good relay.
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 C2 harness connector cavities 1, 3 and 5.
Does the test light illuminate brightly?All
Ye s!Replace the initial Engine Control Relay.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 13
13 Turn the ignition off.
Remove the Engine Control Relay from Fuse Block No.1
Using a 12-volt test light connected to ground, check both Battery (+) circuits at the
Engine Control Relay connector in Fuse Block No.1
Does the test light illuminate brightly for each circuit?All
Ye s!Repair the Engine Control Relay Output circuit for an open
between the Engine Control Relay connector in Fuse Block No. 1
and ECM C2 harness connector cavities 1, 3 and 5. It may be
necessary to replace the Fuse Block No. 1 to repair this circuit.
Perform ROAD TEST VERIFICATION - VER-2.
No!Repair the Battery (+) Supply circuits to the Engine Control
Relay.
Perform ROAD TEST VERIFICATION - VER-2.
14 Turn the ignition off.
Remove the Engine Control Relay from Fuse Block No. 1.
Disconnect the ECM harness connectors.
Measure the resistance of the Engine Control Relay Control circuit.
Is the resistance below 10.0 ohms?All
Ye s!Go To 15
No!Repair the Engine Control Relay Control circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
15 Turn the ignition off.
Remove the Engine Control Relay from Fuse Block No. 1.
Disconnect the ECM harness connectors.
Measure the voltage of the Engine Control Relay Control circuit.
Is the voltage below 1.0 volts?All
Ye s!Replace and program the ECM in accordance with the Service
Information.
Perform ROAD TEST VERIFICATION - VER-2.
No!Repair the Engine Control Relay Control circuit for a short to
voltage.
Perform ROAD TEST VERIFICATION - VER-2.
238
DRIVEABILITY - DIESEL
*CHECKING THE POWER AND GROUNDS ÐContinued
Symptom:
*ENGINE WILL NOT CRANK
POSSIBLE CAUSES
BATTERY CABLE HIGH RESISTANCE
BATTERY CABLES
CHECKING ECM POWER AND GROUNDS
CHECKING FOR TCM CODES
ECM
ECM CODES PRESENT
IGNITION SWITCH OUTPUT (START) CIRCUIT OPEN
MECHANICAL PROBLEM
SKREEM CODES PRESENT
STARTER MOTOR
STARTER MOTOR RELAY
STARTER MOTOR RELAY CIRCUIT(S) OPEN
STARTER MOTOR RELAY CIRCUIT(S) SHORTED TO GROUND
STARTER RELAY CONTROL CIRCUIT SHORTED TO VOLTAGE
STARTER RELAY OUTPUT CIRCUIT OPEN
TEST ACTION APPLICABILITY
1 Turn the ignition off.
NOTE: The battery must be fully charged before diagnosing a no crank
condition.
Inspect the battery cables for corrosion, looseness or other problems.
Is there evidence of problems?All
Ye s!Repair as necessary.
Perform NO START VERIFICATION - VER-1.
No!Go To 2
2 Turn the ignition off.
Remove the Starter Motor Relay from the Fuse/Relay Block.
Connect a test light between cavities 85 and 86 of the Starter Motor Relay connector
in the Fuse/Relay Block connector.
While observing the test light, attempt to start the engine.
Did the test light illuminate when turning the ignition switch to the Crank position?All
Ye s!Go To 3
No!Go To 8
242
DRIVEABILITY - DIESEL