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DTC P0118

DTC P0118  ECT sensor circuit high input 
DETECTION CONDITION 
  • The PCM monitors the ECT sensor signal at PCM terminal 2AH. If the PCM detects the ECT sensor voltage is above 4.58 V for 5s  , the PCM determines that the ECT sensor circuit has malfunction.

Diagnostic support note 
  • This is a continuous monitor (Engine cooling system).
  • The MIL illuminates if the PCM detects the above malfunction condition during 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
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DIAGNOSTIC PROCEDURE

STEP INSPECTION ACTION
1 VERIFY FREEZE FRAME DATA (MODE 12) AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED 
  • Have the FREEZE FRAME DATA (Mode 12) and DIAGNOSTIC MONITORING TEST RESULTS (Engine cooling system related) been recorded?
Yes Go to the next step.
No Record the FREEZE FRAME DATA (Mode 12) and DIAGNOSTIC MONITORING TEST RESULTS on the repair order, then go to the next step.
2 VERIFY RELATED SERVICE BULLETINS AVAILABILITY 
  • Verify related Service Bulletins availability.
  • Is any related Service Bulletins available?
Yes Perform the repair or diagnosis according to the available Service Bulletins.
  • If the vehicle is not repaired, go to the next step.
No Go to the next step.
3 INSPECT ECT SENSOR CONNECTOR AND TERMINALS 
  • 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 or terminals, then go to Step 8.
No Go to the next step.
4 CLASSIFY ECT SENSOR MALFUNCTION OR WIRING HARNESS MALFUNCTION 
  • Access the ECT PID.
  • Connect a jumper wire between ECT sensor terminals A and B.
  • Verify the ECT 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 ).
No Go to the next step.
5 INSPECT PCM CONNECTOR AND TERMINALS 
  • 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 or terminals, then go to Step 8.
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 there any voltage?
Yes Repair or replace the wiring harness for a possible short to power supply, then go to Step 8.
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 terminals (wiring harness-side):
    • ECT sensor terminal A and PCM terminal 2AH
    • ECT sensor terminal B and PCM terminal 2AY
  • Is there continuity?
Yes Go to the next step.
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.
  • Start the engine.
  • Is the same DTC present?
Yes Replace the PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION ).
No Go to the next step.
9 VERIFY AFTER REPAIR PROCEDURE 
Yes Go to the applicable DTC inspection.
(See DTC TABLE ).
No DTC troubleshooting completed.