DTC P0118 (19-21 9-Speed A/T)

DTC P0118  : Engine Coolant Temperature (ECT) Sensor 1 Circuit High Voltage

NOTE:  Before you troubleshoot, review the general troubleshooting information - Refer to: How to Troubleshoot the Fuel and Emissions Systems

DTC (PGM-FI)

1. Problem verification

   -1. Turn the vehicle to the ON mode.

   - 2. Check the parameter (s) below with the HDS.

   Signal	Threshold		Current conditions
   	Values	Unit	Values	Unit
   ECT SENSOR 1	More than 4.92	V

   Do the current condition (s) match the threshold?

   YES 

   The failure is duplicated. Go to step 2.

   NO 

   Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at ECT sensor 1 and the PCM. If the on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the on-board snapshot - Refer to: How to Troubleshoot the Fuel and Emissions Systems

2. ECT sensor 1 check

   -1. Turn the vehicle to the OFF (LOCK) mode.

   - 2. Disconnect the following connector.

   ECT sensor 1 2P connector

   - 3. Connect terminals A and B with a jumper wire.

   Terminal A	ECT sensor 1 2P connector (female terminals) No. 1:
   Terminal B	ECT sensor 1 2P connector (female terminals) No. 2:

   Courtesy of HONDA, U.S.A., INC.

   - 4. Turn the vehicle to the ON mode.

   - 5. Check the parameter (s) below with the HDS.

   Signal	Threshold		Current conditions
   	Values	Unit	Values	Unit
   ECT SENSOR 1	More than 4.92	V

   Do the current condition (s) match the threshold?

   YES 

   Go to step 3.

   NO 

   Replace ECT sensor 1 - Refer to: ECT Sensor 1 Removal and Installation .

3. Determine possible failure area (TW line, others)

   -1. Turn the vehicle to the OFF (LOCK) mode.

   - 2. Remove the jumper wire from the ECT sensor 1 2P connector.

   - 3. Turn the vehicle to the ON mode.

   - 4. Measure the voltage between test points 1 and 2.

   Test condition	Vehicle ON mode
   	ECT sensor 1 2P connector: disconnected
   Test point 1	ECT sensor 1 2P connector (female terminals) No. 2:
   Test point 2	Body ground

   Courtesy of HONDA, U.S.A., INC.

   Is there about 5.0 V?

   YES 

   Go to step 4.

   NO 

   Go to step 5.

4. Open wire check (SG2 line)

   -1. Turn the vehicle to the OFF (LOCK) mode.

   - 2. Jump the SCS line with the HDS, and wait more than 1 minute.

   - 3. Disconnect the following connector.

   PCM connector E (80P)

   - 4. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	ECT sensor 1 2P connector: disconnected
   	PCM connector E (80P): disconnected
   Test point 1	ECT sensor 1 2P connector (female terminals) No. 1:
   Test point 2	PCM connector E (80P) No. 58 - Refer to: PCM Connector for Inputs and Outputs (9-Speed A/T) (2019 2020 2021),

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   The SG2 wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM - Refer to: PCM Removal and Installation (9-Speed A/T 2019 2020 2021) , then recheck. If DTC P0118 goes away and the PCM was substituted, replace the original PCM - Refer to: PCM Removal and Installation (9-Speed A/T 2019 2020 2021) .

   NO 

   Repair an open in the SG2 wire between the PCM (E58) and ECT sensor 1.

5. Open wire check (TW line)

   -1. Turn the vehicle to the OFF (LOCK) mode.

   - 2. Jump the SCS line with the HDS, and wait more than 1 minute.

   - 3. Disconnect the following connector.

   PCM connector E (80P)

   - 4. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	ECT sensor 1 2P connector: disconnected
   	PCM connector E (80P): disconnected
   Test point 1	ECT sensor 1 2P connector (female terminals) No. 2:
   Test point 2	PCM connector E (80P) No. 38 - Refer to: PCM Connector for Inputs and Outputs (9-Speed A/T) (2019 2020 2021)

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   The TW wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM - Refer to: PCM Removal and Installation (9-Speed A/T 2019 2020 2021) , then recheck. If DTC P0118 goes away and the PCM was substituted, replace the original PCM - Refer to: PCM Removal and Installation (9-Speed A/T 2019 2020 2021) .

   NO 

   Repair an open in the TW wire between the PCM (E38) and ECT sensor 1.