DTC P0113 Or P0118 - Temperature Sensor Test (IAT Or ECT): Condition

DTC P0118 (ECT) or P0113 (IAT) indicates corresponding sensor signal is more than self-test maximum. Maximum signal voltage for ECT and IAT sensor is 4.6 volts. Possible causes for excess voltage signals are:

Open circuit in wiring harness (IAT or ECT).
Faulty connection.
Faulty sensor.
Faulty PCM.

1) Induce Opposite DTC Turn ignition off. Disconnect suspect temperature sensor. Connect a jumper wire between signal circuit (ECT or IAT) terminal and SIG RTN terminal at sensor wiring harness connector. With scan tool installed, turn ignition on.

NOTE: If communication link error is displayed, remove jumper wire and go to step 3).

Access ECT V or IAT V PID. If the PID is less than 0.2 volt, replace sensor and repeat QUICK TEST. If PID is 0.2 volt or more, remove jumper wire and go to next step.

2) Check Resistance Of Sensor Signal & SIG RTN Circuits Turn ignition off. Ensure suspect temperature sensor is disconnected. Disconnect PCM 104-pin connector. Check for damaged wiring, and repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between test pin No. 38 (ECT sensor) or test pin No. 39 (IAT sensor) at breakout box and SIG RTN terminal at sensor wiring harness connector. Also, measure resistance between test pin No. 91 (SIG RTN) and SIG RTN circuit at sensor wiring harness connector. If both readings are less than 5 ohms, replace PCM, and repeat QUICK TEST. If either reading is 5 ohms or more, repair open circuit and repeat QUICK TEST.

3) Check For Sensor Signal Short To VREF Turn ignition off. Ensure suspect temperature sensor is disconnected. Measure resistance between test pin No. 90 (VREF) and test pin No. 38 (ECT sensor) or test pin No. 39 (IAT sensor) at breakout box. If resistance is 10,000 ohms or more, replace PCM and repeat QUICK TEST. If either resistance is less than 10,000 ohms, repair short circuit to VREF and repeat QUICK TEST.