P0117 ENGINE COOLANT TEMPERATURE (ECT) SENSOR VOLTAGE TOO LOW
When Monitored and Set Condition:
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 (K104) RETURN CIRCUIT
- WIRING HARNESS SHORTED
- ECM
DIAGNOSTIC PROCEDURE
NOTE: Refer to VERIFICATION TESTS for appropriate verification test procedures.
-
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?
Yes --> Go To 2
No --> Replace the Coolant Temperature sensor. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). -
Reconnect the coolant temp sensor connected. Turn the ignition on. With the DRBIII®, erase DTCs. With the DRBIII®, read DTCs. Did the DTC reset?
Yes --> Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure). Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
No --> Go To 3 -
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) temperature sensor signal circuit at the sensor harness connector. Is the resistance more than 100 k ohms?
Yes --> Go To 4
No --> Repair or replace the short harness. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). -
Measure the resistance between the (K2) signal circuit and all other circuits at the ECM harness connector. Is the resistance more than 100k ohms?
Yes --> Go To 5
No --> Repair or replace shorted wiring harness Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). -
Reconnect the ECM harness connectors. Turn the ignition on. With the DRBIII®, erase DTCs. While monitoring the DRBIII®, Disconnect the temperature sensor harness connector. Did the DTC P0118 set?
Yes --> Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure). Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
No --> Replace the ECM. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL)