P0117

ENGINE COOLANT TEMPERATURE SENSOR





Fault Symptom.
CHECK ENGINE lamp (MIL) on.
Impaired driveability.
Engine reluctant to start.
Any other diagnostic trouble codes (misfiring).

Conditions.
P0117
Shorting to ground.

P0118
Shorting to battery positive (B+)/open circuit

Diagnostic
The performance of the temperature sensor can be ascertained with an ISAT scan tool.

- Connect an ISAT scan tool.
- Turn the ignition switch to the ON position.
- Select "READ FUNCTIONS".
- Select "COOLANT TEMPERATURE".

If the temperature sensor is in proper working order the ISAT scan tool should show the current temperature of the coolant.

Check the Wiring
Intermittent faults may occur as a result of temporary short circuits and breaks in the wiring. Jiggle the wiring at several points and in different directions to ascertain whether the wiring harness, including any connectors, is causing the trouble. Observe the multimeter, ISAT scan tool or test lamp while doing this.





Diagnostic Procedure.
1 Check the temperature sensor's ground connection

- Unplug the temperature sensor's 2-pin connector.
- Turn the ignition switch to the ON position.
- Connect the test lamp to:
^ Battery positive (B+) and pin 2.
The test lamp should light up.

Did the test lamp light up?

YES:
^ Continue with point 2.

NO:
^ Repair or replace the wiring. Continue with point 3.





2 Check the control module's temperature sensor input

- Connect an ISAT scan tool.
- Turn the ignition switch to the ON position.
- Select "READ FUNCTIONS".
- Select "COOLANT TEMPERATURE".
The ISAT scan tool should show a reading of 5 V.
- Connect a jumper lead between pins 1 and 2 of the temperature sensor's connector.
The ISAT scan tool should show a reading of 0 V.

Are both readings OK?

YES:
^ Change the temperature sensor. Continue with point 3.

NO:
^ Check the relevant lead and repair or replace it if necessary. Continue with point 3.





3 Final check

- Clear the diagnostic trouble code.
- Implementation of driving cycle:
^ Drive the car at varying loads and engine rpm for 5 minutes.
- Evaluation of driving cycle:
^ Check whether the diagnostic trouble code has recurred.

Has the diagnostic trouble code recurred?

YES:
^ Continue at "Procedure Before Replacing a Control Module".

NO:
^ The steps taken to rectify the fault were correct.