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2008 - MX-5 - Engine

DTC P0117 [LF]



DTC P0117

ECT sensor circuit low input

DETECTION CONDITION

  • The PCM monitors the ECT sensor signal at PCM terminal 2AH. If the PCM detects the ECT sensor voltage below 0.2 V, 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.

  • PENDING CODE is available if the PCM detects the above malfunction condition.

  • FREEZE FRAME DATA is available.

  • The DTC is stored in the PCM memory.

POSSIBLE CAUSE

  • ECT sensor malfunction

  • Connect or terminal malfunction

  • Short to ground in wiring harness between ECT sensor terminal A and PCM terminal 2AH

  • Short each wiring harness ECT sensor signal circuit and ECT sensor ground circuit

  • PCM malfunction


Diagnostic procedure

STEP

INSPECTION

ACTION

1

VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED
  • Have FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS (Engine cooling system related) been recorded?

Yes

Go to the next step.

No

Record the FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS 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.

No

Go to the next step.

3

INSPECT TERMINAL BENT
  • Turn the ignition switch off.

  • Disconnect the ECT sensor connector.

  • Inspect for bent of ECT sensor terminals A and B (part-side).

  • Is there any malfunction?

Yes

Repair or replace the terminal, then go to Step 7.

No

Go to the next step.

4

CLASSIFY ECT SENSOR MALFUNCTION OR WIRING HARNESS MALFUNCTION
  • Connect the M-MDS to DLC-2.

  • Access ECT PID.

  • Verify ECT value when disconnecting ECT sensor connector.

  • Does the ECT value change?

Yes

Replace the ECT sensor, then go to Step 7.

(See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [LF].)

No

Go to the next step.

5

INSPECT ECT SENSOR SIGNAL CIRCUIT FOR SHORT TO GROUND
  • Turn the ignition switch off.

  • Inspect for continuity between ECT sensor terminal A (wiring harness-side) and body ground.

  • Is there continuity?

Yes

Repair or replace the wiring harness for short to ground, then go to Step 7.

No

Go to the next step.

6

INSPECT ECT SENSOR CIRCUIT FOR SHORT WIRING HARNESSES
  • Inspect for continuity between ECT sensor terminal A and B (wiring harness-side).

  • Is there continuity?

Yes

Repair or replace the wiring harness for short, then go to the next step.

No

Go to the next step.

7

VERIFY TROUBLESHOOTING OF DTC P0117 COMPLETED
  • Make sure to reconnect all disconnected connectors.

  • Clear the DTC from the PCM memory using the M-MDS.

  • Start the engine, or perform the KOEO self-test with M-MDS.

    (SeeKOEO/KOER SELF TEST [LF].)

  • Is the same DTC present?

Yes

Replace the PCM, then go to the next step.

(See PCM REMOVAL/INSTALLATION [LF].)

No

Go to the next step.

8

VERIFY AFTER REPAIR PROCEDURE

Yes

Go to the applicable DTC troubleshooting.

(See DTC TABLE [LF].)

No

Troubleshooting completed.




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