DTC P0117: ENGINE COOLANT TEMPERATURE SENSOR VOLTAGE TOO LOW
Monitor & Set Conditions
Engine Coolant Temperature (ECT) sensor voltage is monitored when the ignition is on and battery voltage is greater than 10.4 volts. DTC may be stored when ECT sensor voltage at Engine Control Module (ECM) is less than .8 volt for greater than 2 seconds.
- Intermittent Wiring Problem
- ECT Sensor Signal Circuit Shorted To Ground
- ECT Sensor Signal Circuit Shorted To Sensor Ground
- ECT Sensor
1. Turn ignition on with engine off. Using DRBIII(R) scan tool, read ECT sensor voltage. If ECT sensor voltage is less than .8 volt, go to next step. If ECT sensor voltage is .8 volt or greater, go to step 5.
2. Turn ignition off. Disconnect ECT sensor harness connector. The ECT sensor is located at the front of the cylinder head, near the thermostat housing. Turn ignition on with engine off. Using scan tool, read ECT sensor voltage. If ECT sensor voltage is 4 volts or less, go to next step. If ECT sensor voltage is greater than 4 volts, replace the ECT sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article.
3. Ensure ignition is off and ECT sensor connector is still disconnected. Disconnect ECM harness connector. ECM is located on driver's side of the engine, just in front of fuel transfer pump and contains a 50-pin connector. Using DVOM, measure resistance between ground and terminal "B" (Tan/Black wire) on ECT sensor harness connector. If resistance is 100 ohms or greater, go to next step. If resistance is less than 100 ohms, repair short to ground in Tan/Black wire between ECT sensor and ECM.
4. Using DVOM, measure resistance between ECT sensor harness connector terminals. If resistance is less than 100 ohms, repair short to sensor ground in Tan/Black wire between ECT sensor and ECM. If resistance is 100 ohms or greater, replace and program the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article.
5. The conditions that set the DTC are not present at this time. With ignition on engine off, monitor scan tool parameters related to the DTC while wiggling wiring harness. Look for parameter values to change and/or a DTC to set. Review the DRBIII(R) Freeze Frame information. 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 wire harness. Look for any chafed, pierced, pinched or partially broken wires. Visually inspect the related wire harness connectors. Look for broken, bent, pushed out or corroded terminals. Was any of the above conditions present? If yes, repair as necessary. If no, the test is complete.