What P0118 means
The coolant temperature signal is implausibly high-resistance, so the ECU cannot tell how warm the engine is and defaults to a rich fuelling strategy.
Common causes
- Failed coolant temperature sensor
- Open wiring or corroded connector
- Low coolant level
How it is usually fixed
- 1Check coolant level
- 2Inspect the connector for corrosion
- 3Replace the ECT sensor
Other common codes
- P0011 — Camshaft Position A – Timing Over-Advanced (Bank 1)
- P0030 — HO2S Heater Control Circuit (Bank 1, Sensor 1)
- P0101 — Mass Air Flow Circuit Range/Performance
- P0113 — Intake Air Temperature Sensor Circuit High
- P0131 — O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1)
- P0138 — O2 Sensor Circuit High Voltage (Bank 1, Sensor 2)
Code information is general guidance, not a diagnosis for a specific vehicle. Confirm with live data and manufacturer test procedures before replacing parts.