Page 1249 of 4284

TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the ECT Sensor harness connector.
Connect a jumper wire between the ECT Sensor harness connector cavities.
Turn the ignition on.
With the DRB, read the ECT Sensor voltage.
Is the voltage below 1.0 volt?All
Ye s®Replace the ECT Sensor in accordance with the Service Informa-
tion.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 4
4 Turn the ignition off.
Disconnect the ECT Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the ECT Sensor Ground circuit.
Is the resistance below 5.0 ohms?All
Ye s®Go To 5
No®Repair the ECT Sensor Ground circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
5 Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the ECT Sensor harness connector.
Measure the resistance of the ECT Sensor Signal circuit.
Is the resistance below 10.0 ohms?All
Ye s®Go To 6
No®Repair the ECT Sensor Signal circuit for an open.
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.
30
DRIVEABILITY - DIESEL
P0115-ENGINE COOLANT TEMP SENSOR CIRCUIT SIGNAL VOLTAGE
TOO HIGH Ð
Continued
Page 1250 of 4284

TEST ACTION APPLICABILITY
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.
31
DRIVEABILITY - DIESEL
P0115-ENGINE COOLANT TEMP SENSOR CIRCUIT SIGNAL VOLTAGE
TOO HIGH Ð
Continued
Page 1251 of 4284

Symptom:
P0115-ENGINE COOLANT TEMP SENSOR CIRCUIT SIGNAL VOLT-
AGE TOO LOW
When Monitored and Set Condition:
P0115-ENGINE COOLANT TEMP SENSOR CIRCUIT SIGNAL VOLTAGE TOO
LOW
When Monitored: With the ignition on.
Set Condition: The Engine Coolant Temperature Sensor Signal voltage is below 0.2 volt
for more than 1 second.
POSSIBLE CAUSES
INTERMITTENT CONDITION
ECT SENSOR
ECT SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
ECT SENSOR SIGNAL AND GROUND CIRCUITS SHORTED TOGETHER
ENGINE CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, monitor the Engine Coolant Temperature (ECT) Sensor voltage.
Is the ECT Sensor voltage below 0.3 volt?All
Ye s®Go To 2
No®Go To 6
2 Turn the ignition off.
Disconnect the ECT Sensor harness connector.
Turn the ignition on.
With the DRB, read the ECT Sensor voltage.
Is the voltage above 4.0 volts?All
Ye s®Replace the ECT Sensor in accordance with the Service Informa-
tion.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 3
3 Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the ECT Sensor harness connector.
Measure the resistance between ground and the ECT Sensor Signal circuit.
Is the resistance above 1000 ohms?All
Ye s®Go To 4
No®Repair the ECT Sensor Signal circuit for a short to ground.
Perform ROAD TEST VERIFICATION - VER-2.
32
DRIVEABILITY - DIESEL
Page 1252 of 4284

TEST ACTION APPLICABILITY
4 Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the ECT Sensor harness connector.
Measure the resistance between the ECT Sensor Signal circuit and Sensor Ground
circuit.
Is the resistance above 1000 ohms?All
Ye s®Go To 5
No®Repair the ECT Sensor Signal and Ground circuits for a short
together.
Perform ROAD TEST VERIFICATION - VER-2.
5 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.
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.
33
DRIVEABILITY - DIESEL
P0115-ENGINE COOLANT TEMP SENSOR CIRCUIT SIGNAL VOLTAGE
TOO LOW Ð
Continued
Page 1253 of 4284

Symptom:
P0190-FUEL PRESS SENSOR CIRCUIT MALF SIGNAL VOLTAGE
TOO HIGH
When Monitored and Set Condition:
P0190-FUEL PRESS SENSOR CIRCUIT MALF SIGNAL VOLTAGE TOO HIGH
When Monitored: With the ignition on.
Set Condition: The Fuel Rail Pressure Sensor Signal voltage is above 4.8 volts.
POSSIBLE CAUSES
ECM - FUEL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE
ECM - FUEL PRESSURE SENSOR SIGNAL OPEN
FUEL PRESSURE SENSOR SIGNAL CIRCUIT OPEN
FUEL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE
SENSOR GROUND CIRCUIT OPEN
INTERMITTENT CONDITION
5-VOLT SUPPLY CIRCUIT OPEN
SENSOR GROUND CIRCUIT SHORTED TO VOLTAGE
FUEL PRESSURE SENSOR
ENGINE CONTROL MODULE
TEST ACTION APPLICABILITY
1WARNING: THE FUEL INJECTION PUMP SUPPLIES HIGH PRESSURE
FUEL TO EACH INDIVIDUAL INJECTOR THROUGH HIGH-PRESSURE
FUEL LINES. FUEL UNDER HIGH PRESSURE CAN PENETRATE SKIN
AND CAUSE PERSONAL INJURY. WEAR SAFETY GOGGLES AND ADE-
QUATE PROTECTIVE CLOTHING.
Turn the ignition on.
With the DRB III, erase ECM DTCs.
Cycle the ignition key on and off several times, leaving the key on for at least 10
seconds at a time.
With the DRB III, read ECM DTCs.
Did this DTC reset?All
Ye s®Go To 2
No®Go To 10
34
DRIVEABILITY - DIESEL
Page 1254 of 4284

TEST ACTION APPLICABILITY
2 Turn the ignition off.
Disconnect the Fuel Pressure Sensor harness connector.
Turn the ignition on.
Measure the voltage of the Fuel Pressure Sensor Signal circuit.
Select the appropriate voltage reading.All
Voltage is above 5.5 volts.
Go To 3
Voltage is between 4.7 and 5.4 volts.
Go To 4
Voltage is below 4.7 volts.
Go To 9
3 Turn the ignition off.
Disconnect the Fuel Pressure Sensor harness connector.
Disconnect the ECM harness connectors.
Remove the ECM/PCM Relay from the IPM.
Connect a jumper wire between cavity 30 and cavity 87 of the ECM/PCM Relay
connector.
Turn the ignition on.
Measure the voltage of the Fuel Pressure Sensor Signal 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 Fuel Pressure Sensor Signal circuit for a short to
voltage.
Perform ROAD TEST VERIFICATION - VER-2.
4 Turn the ignition off.
Disconnect the Fuel Pressure Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the Sensor Ground circuit.
Is the resistance below 5.0 ohms?All
Ye s®Go To 5
No®Repair the Sensor Ground circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
5 Turn the ignition off.
Disconnect the Fuel Pressure Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the 5-Volt Supply circuit.
Is the resistance below 5 ohms?All
Ye s®Go To 6
No®Repair the 5-volt Supply circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
35
DRIVEABILITY - DIESEL
P0190-FUEL PRESS SENSOR CIRCUIT MALF SIGNAL VOLTAGE TOO
HIGH Ð
Continued
Page 1255 of 4284

TEST ACTION APPLICABILITY
6 Turn the ignition off.
Disconnect the Fuel Pressure Sensor harness connector.
Disconnect the ECM harness connectors.
Remove the ECM/PCM Relay from the PDC.
Connect a jumper wire between cavity 30 and cavity 87 of the ECM/PCM Relay
connector.
Turn the ignition on.
Measure the voltage of the Sensor Ground circuit at the Fuel Pressure Sensor and
ECM harness connectors.
Is the voltage above 1.0 volt at either connector?All
Ye s®Repair the Sensor Ground circuit for a short to voltage.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 7
NOTE: If the Sensor Ground circuit had a short to voltage on it, the ECM
may have been damaged. Retest the Fuel Pressure Sensor circuit.
7 Turn the ignition off.
Disconnect the Fuel Pressure Sensor harness connector.
Connect a jumper wire between the Fuel Pressure Sensor Signal circuit and the
Sensor Ground circuit in the Fuel Pressure Sensor harness connector.
Turn the ignition on and monitor the DRB for DTCs.
Is DTC P0190-FUEL PRESS SENSOR CIRCUIT MALF SIGNAL VOLTAGE TOO
LOW present?All
Ye s®Replace the Fuel Pressure Sensor.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 8
8 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.
9 Turn the ignition off.
Disconnect the Fuel Pressure Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the Fuel Pressure Sensor Signal circuit.
Is the resistance below 5.0 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 Pressure Sensor Signal circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
36
DRIVEABILITY - DIESEL
P0190-FUEL PRESS SENSOR CIRCUIT MALF SIGNAL VOLTAGE TOO
HIGH Ð
Continued
Page 1256 of 4284

TEST ACTION APPLICABILITY
10WARNING: 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.
37
DRIVEABILITY - DIESEL
P0190-FUEL PRESS SENSOR CIRCUIT MALF SIGNAL VOLTAGE TOO
HIGH Ð
Continued