Error code

OBD2 P0118

OBD2P0118
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Engine Coolant Temperature Circuit High.

Severity

moderateCan drive, but performance issues may occur.

Summary

P0118 indicates a high input voltage from the engine coolant temperature (ECT) sensor circuit. This code suggests an issue with the sensor or its wiring.

Symptoms

  • Check Engine Light is on
  • Poor fuel economy
  • No start condition
  • Vehicle starts but runs poorly, misfiring

Common Causes

  • Bad connection at the ECT sensor
  • Short in the voltage feed between the sensor and ECM/PCM
  • Defective ECT sensor (shorted internally)

Diagnosis

  1. Verify that the actual engine temperature differs from the scan tool reading by no more than 10°F (5°C).
  2. Check for damage or corrosion in the ECT sensor wiring and connector.
  3. Test the ECT sensor resistance while running the engine to ensure it matches expected values.

Fixes

  • Replace the faulty ECT sensor if necessary.

FAQ

What should I do if my Check Engine Light comes on with P0118?

First, check for any damage or corrosion in the ECT sensor wiring and connector. If no issues are found, test the resistance of the ECT sensor while running the engine to ensure it matches expected values.

View source

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.

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