Page 507 of 5267
5.(K916) RETURN CIRCUIT OPEN
Measure the resistance of the sensor (K916) Return circuit between the
sensor harness connector and the ECM harness connector.
Is the resistance less than 10 Ohms?
Ye s>>
Go To 6
No>>
Repair the open (K916) return circuit or the harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
6.SHORT IN HARNESS
Check for a short circuit from (K21) signal circuit to all other circuits at
the ECM harness connector.
Istheresistancemorethan100kohms?
Ye s>>
Go To 7
No>>
Repair the short in the wiring harness or replace the har-
ness.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 512 of 5267

When Monitored:
With 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
COOLANT TEMPERATURE SENSOR
INTERMITTENT CONDITION
(K2) SENSOR SIGNAL CIRCUIT SHORTED TO GROUND OR (K914) RETURN CIRCUIT
WIRING HARNESS SHORTED
ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.COOLANT TEMPERATURE SENSOR
Turn the ignition off.
Disconnect the Coolant Temp sensor harness connector.
Check connectors - Clean/repair as necessary.
Measure the resistance of the Temp 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 coolant temp sensor connected.
Turn the ignition on.
With the scan tool, erase DTCs.
With the scan tool, read DTCs.
Did the DTC reset?
Ye s>>
Refer to the INTERMITTENT CONDITION Symptom (Diagnostic Procedure). (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
No>>
Go To 3
Page 513 of 5267
3.(K2) SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the ECM harness connector.
Check connectors - Clean/repair as necessary.
Measure the resistance between the engine ground and the (K2) tem-
perature sensor signal circuit at the sensor harness connector.
Istheresistancemorethan100kohms?
Ye s>>
Go To 4
No>>
Repair or replace the short harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
4.WIRING HARNESS SHORTED
Measure the resistance between the (K2) signal circuit and all other cir-
cuits at the ECM harness connector.
Istheresistancemorethan100kohms?
Ye s>>
Go To 5
No>>
Repair or replace shorted wiring harness
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
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 517 of 5267
3.HIGH RESISTANCE IN CIRCUIT
Turn the ignition off.
Disconnect the ECM harness connector.
Check connectors - Clean/repair as necessary.
Measure the resistance between the (K2) temperature sensor signal
and (K914) return circuit at the ECM harness connector with the coolant
temp sensor harness connected.
Is the resistance between 300 and 90k ohms?
Ye s>>
Go To 6
No>>
Go To 4
4.(K2) SIGNAL CIRCUIT OPEN
Disconnect the coolant temperature sensor harness connector.
Measure the resistance of the (K2) coolant temperature sensor signal
circuit between the coolant temperature sensor connector and the ECM
connector.
Is the resistance less than 10 Ohms?
Ye s>>
Go To 5
No>>
Repair or replace the open (K2) signal circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 521 of 5267

P0148-HIGH PRESSURE COMMON RAIL (HPCR) CHECKSUM
For a complete wiring diagramRefer to Section 8W.
When Monitored:
While the engine is running.
Set Condition:
A deviation between the fuel pressure set point and the actual fuel pressure.
Possible Causes
OTHERS DTC’S PRESENT
FUEL LEAKS
FUEL CONTROL ACTUATOR
FUEL PRESSURE SENSOR
CASCADE OVERFLOW VALVE
CHECK VALVE DAMAGED OR BLOCKED
FUEL RETURN LINES OBSTRUCTION, DAMAGE, OR DEBRIS
LIFT PUMP FLOW
AIRINFUELSYSTEM
LEAKING FUEL INJECTORS OR HIGH PRESSURE CONNECTORS
PRESSURE LIMITING VALVE
HIGH PRESSURE FUEL PUMP
INTERMITTENT CONDITION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.OTHERS DTC’S PRESENT
With the scan tool, read DTCs.
Are any other DTC’s present?
Ye s>>
Repair other DTC’s first.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
No>>
Go To 2
2.FUEL LEAKS
Ensure that the fuel level is above 15% using the scan tool.
Visually inspect the low and high pressure side of the fuel system for fuel leaks or damaged components.
Do you have any fuel leaks or damaged components?
Ye s>>
Repair the fuel leak.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 3
Page 522 of 5267

3.FUEL CONTROL ACTUATOR
Check for a mechanically stuck Fuel Control Actuator (FCA). Using the scantool, actuate the fuel control actuator.
NOTE: The fuel control actuator will only click when cycled off..
Do you hear a click from the actuator when you cycle the actuator off with thescan tool?
Ye s>>
Go To 4
No>>
Replace the fuel Injector pump.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
4.FUEL PRESSURE SENSOR
Using the scan tool, monitor the fuel pressure reading from the fuel rail pressure sensor at idle and at 2000 RPM
Is the fuel rail pressure reading higher at 2000 RPM than at idle?
Ye s>>
Go To 5
No>>
Replace the fuel pressure sensor.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
5.HIGH FUEL PRESSURE
Using the scan tool compare the fuel rail pressure set point with the actualfuel rail pressure.
Is the actual fuel rail pressure higher than the fuel rail pressure set point?
Ye s>>
Go To 6
No>>
Go To 9
6.CASCADE OVERFLOW VALVE
Perform the no trouble code test*fuel pump return flow test. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
Did the fuel injection pump pass the test?
Ye s>>
Go To 7
No>>
Replace the Fuel pump.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
7.CHECK VALVE DAMAGED OR BLOCKED
Check the fuel drain line check valve in the rear of the cylinder head for signs of damage, blockage, or debris.
Is the check valve damaged or blocked?
Ye s>>
Repair the cause of the damaged or blocked check valve or replace the valve.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 8
Page 523 of 5267

8.FUEL RETURN LINE OBSTRUCTION, DAMAGED OR DEBRIS
Check the fuel return lines for signs of obstruction, damage, or debris.
Are the fuel drain lines damaged or blocked?
Ye s>>
Repair cause of high fuel drain line restriction.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 9
9.LIFT PUMP FLOW
Perform the no trouble code*LIFT PUMP FLOW TEST. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
Did the Lift pump pass the test?
Ye s>>
Go To 10
No>>
Replace the Lift Pump.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
10.PRESSURE LIMITING VALVE
Perform the no trouble code test*PRESSURE LIMITING VALVE ON THE FUEL RAIL FOR INTERNAL LEAKS.
Did the pressure limiting valve pass the test procedure?
Ye s>>
Go To 11
No>>
Replace the Pressure Limiting Valve.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
11 .LEAKING FUEL INJECTORS OR HIGH PRESSURE CONNECTORS
Perform the no trouble test*INJECTOR RETURN FLOW TEST. (Refer to 9 - ENGINE - DIAGNOSIS AND TEST-
ING)
Are any Injectors leaking or high pressure connectors leaking?
Ye s>>
Replace or repair the leaking fuel injectors or high pressure connectors.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 12
12.HIGH PRESSURE FUEL PUMP
Perform the no trouble code test*HIGH PRESSURE FUEL PUMP PERFORMANCE TEST. (Refer to 9 - ENGINE
- DIAGNOSIS AND TESTING)
Did the fuel pump pass the high pressure fuel pump performance test?
Ye s>>
Refer to the INTERMITTENT CONDITION Symptom (Diagnostic Procedure). (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
No>>
Replace the High pressure fuel pump.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)