April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC P0118

DTC P0118

ECT sensor circuit high input

DETECTION CONDITION

The PCM monitors the input voltage from the ECT sensor when the engine is running. If the input voltage is more than 4.8 V, the PCM determines that the ECT sensor circuit input voltage is high.

Diagnostic support note

This is a continuous monitor (CCM).
The MIL illuminates if the PCM detects the above malfunction condition in the first drive cycle.
FREEZE FRAME DATA (Mode 2/Mode 12) is available.
The DTC is stored in the PCM memory.

POSSIBLE CAUSE

ECT sensor connector or terminals malfunction
ECT sensor malfunction
PCM connector or terminals malfunction
Short to power supply in wiring harness between ECT sensor terminal A and PCM terminal 2AH
Open circuit in wiring harness between ECT sensor terminal A and PCM terminal 2AH
Open circuit in wiring harness between ECT sensor terminal B and PCM terminal 2AY
PCM malfunction

G07878105

DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA (MODE 12) HAS BEEN RECORDED Has the FREEZE FRAME DATA (Mode 12) been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA (Mode 12) on the repair order, then go to the next step.
2	VERIFY RELATED REPAIR INFORMATION AVAILABILITY Verify related Service Bulletins and/or on-line repair information availability. Is any related repair information available?	Yes	Perform repair or diagnosis according to the available repair information. If the vehicle is not repaired, go to the next step.
2		No	Go to the next step.
3	INSPECT ECT SENSOR CONNECTOR FOR POOR CONNECTION Turn the ignition switch off. Disconnect the ECT sensor connector. Inspect for poor connection (such as damaged/pulled-out pins, corrosion). Is there any malfunction?	Yes	Repair or replace the connector and/or terminals, then go to Step 8.
3		No	Go to the next step.
4	CLASSIFY ECT SENSOR MALFUNCTION OR WIRING HARNESS MALFUNCTION Access the ECT PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST ). Connect a jumper wire between ECT sensor terminal A and B (wiring harness-side). Verify the ECT PID value. Is the voltage 4.58 V or below?	Yes	Replace the ECT sensor, then go to Step 8. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION ).
4		No	Go to the next step.
5	INSPECT PCM CONNECTOR FOR POOR CONNECTION Turn the ignition switch off. Disconnect the PCM connector. Inspect for poor connection (such as damaged/pulled-out pins, corrosion). Is there any malfunction?	Yes	Repair or replace the connector and/or terminals, then go to Step 8.
5		No	Go to the next step.
6	INSPECT ECT SENSOR SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY ECT sensor and PCM connectors are disconnected. Turn the ignition switch to the ON position (engine off). Measure the voltage between ECT sensor terminal A (wiring harness-side) and body ground. Is the voltage B+?	Yes	Repair or replace the wiring harness for a possible power supply, then go to Step 8.
6		No	Go to the next step.
7	INSPECT ECT SENSOR CIRCUIT FOR OPEN CIRCUIT ECT sensor and PCM connectors are disconnected. Turn the ignition switch off. Inspect for continuity between the following circuits: ECT sensor terminal A (wiring harness-side) and PCM terminal 2AH (wiring harness-side) ECT sensor terminal B (wiring harness-side) and PCM terminal 2AY (wiring harness-side) Is there continuity?	Yes	Go to the next step.
7		No	Repair or replace the wiring harness for a possible open circuit, then go to the next step.
8	VERIFY TROUBLESHOOTING OF DTC P0118 COMPLETED Make sure to reconnect all disconnected connectors. Clear the DTC from the PCM memory using the M-MDS. (See AFTER REPAIR PROCEDURE ). Perform the KOEO or KOER self test. (See KOEO/KOER SELF TEST ). Is the same DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION ).
8		No	Go to the next step.
9	VERIFY AFTER REPAIR PROCEDURE Perform the "AFTER REPAIR PROCEDURE ". (See AFTER REPAIR PROCEDURE ). Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE ).
9		No	DTC troubleshooting completed.