Page 516 of 5267

When Monitored:
With ignition on and battery voltage greater than 10.4 volts.
Set Condition:
The circuit voltage to the ECM is above a calibrated threshold for a certainperiod of time.
Possible Causes
COOLANT TEMPERATURE SENSOR
INTERMITTENT CONDITION
(K2) SIGNAL CIRCUIT OPEN
(K914) SENSOR RETURN CIRCUIT OPEN
(K2) SIGNAL CIRCUIT SHORTED
ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.COOLANT TEMPERATURE SENSOR
Disconnect the coolant temperature sensor harness connector.
Check connectors - Clean/repair as necessary.
Measure the resistance of the coolant temperature sensor.
Is the resistance between 300 and 90k ohms?
Ye s>>
Go To 2
No>>
Replace the coolant temperature sensor.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
2.INTERMITTENT CONDITION
Reconnect the disconnected coolant temp sensor harness connector.
With the scan tool, erase DTCs.
With the scan tool, read DTCs.
Did the DTC return?
Ye s>>
Go To 3
No>>
Refer to the INTERMITTENT CONDITION Symptom (Diagnostic Procedure). (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Page 529 of 5267

When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.
Set Condition:
The circuit voltage to the ECM falls below a calibrated threshold for a certain period of time.
Possible Causes
OTHER DTC’S
FUEL PRESSURE SENSOR
(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO (F855) RETURN CIRCUIT
(K181) SIGNAL CIRCUIT SHORTED TO (F855) RETURN CIRCUIT
(K181) SIGNAL CIRCUIT OPEN
(F855) 5-VOLT SUPPLY CIRCUIT OPEN
(K181) SIGNAL CIRCUIT SHORTED TO GROUND
(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
ECM
INTERMITTENT CONDITION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.OTHER DTC’S
Ignition on, engine not running.
With the scan tool, read DTCs.
Do you have multiple DTC’s?
Ye s>>
Repair other DTC’s first.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 2
2.(F855) 5-VOLT SUPPLY AND (K915) RETURN CIRCUIT
Turn the ignition off.
Disconnect the Fuel Pressure sensor harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Ignition on, engine not running.
Measure the voltage between the (F855) 5-volt supply and (K915)
return circuits of the Fuel pressure sensor harness connector.
Is the voltage between 4.5 and 5.5 volts?
Ye s>>
Go To 3
No>>
Go To 4
Page 532 of 5267

8.(K181) SIGNAL CIRCUIT SHORTED TO GROUND
Measure the resistance between the (K181) signal circuit in the sensor
harness connector and battery negative.
Is the resistance greater than 100 K Ohms?
Ye s>>
Go To 9
No>>
Repair (K181) signal circuit shorted to ground.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
9.(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
Measure the resistance between the (F855) 5-volt supply circuit in the
sensor harness connector and battery negative.
Is the resistance greater than 100 K Ohms?
Ye s>>
Go To 10
No>>
Repair (F855) 5-volt Supply circuit shorted to ground.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
10.ECM
Reconnect the disconnected Fuel pressure sensor harness connector and ECM harness connectors.
While monitoring scan tool, disconnect the Fuel Pressure sensor connector.
Does the DTC P0193 set?
Ye s>>
Te s t C o m p l e t e .
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Replace the ECM.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 534 of 5267

When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.
Set Condition:
The circuit voltage to the ECM is above a calibrated threshold for a certainperiod of time.
Possible Causes
OTHER DTC’S
FUEL PRESSURE SENSOR
(K181) SIGNAL CIRCUIT SHORTED TO VOLTAGE
(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
(K181) SIGNAL CIRCUIT SHORTED TO (F855) 5-VOLT SUPPLY CIRCUIT
(K915) RETURN CIRCUIT OPEN
ECM
INTERMITTENT CONDITION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.OTHER DTC’S
Ignition on, engine not running.
With the scan tool, read DTCs.
Do you have multiple DTC’s?
Ye s>>
Refer to multiple fault troubleshooting tree.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 2
2.(F855) 5-VOLT SUPPLY AND (K915) RETURN CIRCUIT
Turn the ignition off.
Disconnect the Fuel Pressure sensor harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Ignition on, engine not running.
Measure the voltage between the (F855) 5-volt supply and (K915)
return circuits of the Fuel pressure sensor harness connector.
Is the voltage between 4.5 and 5.5 volts?
Ye s>>
Go To 3
No>>
Go To 4
Page 535 of 5267

3.FUEL PRESSURE SENSOR
While monitoring scan tool, connect a jumper wire between the (K181)
signal circuit and the (K915) return circuit of the Fuel Pressure sensor
connector.
Does the DTC P0192 set?
Ye s>>
Replace the Fuel Pressure Sensor.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
No>>
Go To 4
4.(K181) SIGNAL CIRCUIT SHORTED TO VOLTAGE
Turn the ignition off.
Disconnect the Fuel Pressure sensor harness connector.
Disconnect the ECM harness connectors.
Check connectors - Clean/repair as necessary.
Turn the ignition on.
Measure the voltage between the (K181) signal circuit of the sensor
harness connector and battery negative.
Is the voltage less than 1 volt?
Ye s>>
Go To 5
No>>
Repair the (K181) signal circuit shorted to voltage.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
5.(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
Measure the voltage between the (F855) 5-volt supply circuit of the sen-
sor harness connector and battery negative.
Is the voltage less than 1 volt?
Ye s>>
Go To 6
No>>
Repair the (F855) 5-volt supply circuit shorted to voltage.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 571 of 5267

When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.
Set Condition:
The circuit voltage to the ECM falls below a calibrated threshold for a certain period of time.
Possible Causes
OTHER DTC’S
(K37) SIGNAL CIRCUIT SHORTED TO (K916) SENSOR RETURN CIRCUIT
(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO (K916) SENSOR RETURN CIRCUIT
MAP SENSOR
(K37) SIGNAL CIRCUIT OPEN
(F855) 5-VOLT SUPPLY CIRCUIT OPEN
MAP SENSOR (K37) SIGNAL CIRCUIT SHORT TO GROUND
ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.OTHER DTC’S
Turn the ignition on.
With the scan tool, read the Engine DTC’s.
Is there a 5-volt Supply DTC set?
Ye s>>
Refer to symptom list for problems related to the 5-volt Supply DTC.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 2
2.HIGH VOLTAGE
Turn the ignition off.
Disconnect the Map sensor harness connector.
Check connectors - Clean/repair as necessary.
Turn the ignition on.
Measure the voltage between the (F855) 5-volt supply circuit and sen-
sor (K916) return circuit of the Map sensor harness connector.
Is the voltage between 4.5 and 5.5 volts?
Ye s>>
Go To 3
No>>
Go To 4
Page 574 of 5267

8.MAP SENSOR SIGNAL (K37) CIRCUIT SHORTED TO GROUND
Measure the resistance between the MAP Sensor Signal (K37) circuit
and the Battery negative terminal.
Is the resistance above 100k ohms?
Ye s>>
Go To 9
No>>
Repair the MAP Sensor (K37) Signal circuit for a short to
ground.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
9.(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO (K916) RETURN CIRCUIT OR GROUND
Measure the resistance between the (F855) 5-volt supply circuit in the
sensor harness connector and battery negative.
Is the resistance above 100k ohms?
Ye s>>
Go To 10
No>>
Te s t C o m p l e t e .
10.ECM
Reconnect the ECM harness 60 pin connector.
While monitoring the scan tool, jumperthe (F855) 5-volt supply circuit to
the (K37) signal circuit in the map sensor harness connector.
Did the P0238-MAP SENSOR VOLTAGE TOO HIGH, DTC set?
Ye s>>
Te s t C o m p l e t e .
No>>
Replace and program the ECM in accordance with the Ser-
vice Information.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 576 of 5267

When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.
Set Condition:
The circuit voltage to the ECM is above a calibrated threshold for a certainperiod of time.
Possible Causes
OTHER DTC’S
(K37) SIGNAL CIRCUIT SHORTED TO BATTERY
(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO BATTERY
MAP SENSOR
(K37) SIGNAL CIRCUIT SHORT TO SUPPLY
(F855) 5-VOLT SUPPLY CIRCUIT SHORT TO BATTERY
INTERMITTENT
ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.OTHER DTC’S
Turn the ignition on.
With the scan tool, read the Engine DTC’s.
Is there a 5-volt Supply DTC set?
Ye s>>
Refer to symptom list for problems related to the 5-volt Supply DTC.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 2
2.HIGH VOLTAGE
Turn the ignition off.
Disconnect the Map sensor harness connector.
Check connectors - Clean/repair as necessary.
Turn the ignition on.
Measure the voltage between the (F855) 5-volt supply circuit and
(K916) sensor return circuit of the Map sensor harness connector.
Is the voltage between 4.5 and 5.5 volts?
Ye s>>
Go To 3
No>>
Go To 4