Error Code P0118
Critical Issue
DTC Code P0118 indicates a high voltage issue in the Engine Coolant Temperature Sensor Circuit, suggesting a deviation from the normal operating range as monitored by the Engine Control Module (ECM).
What symptoms indicate Error Code P0118?
- Engine Light ON: The Engine Light or Service Engine Soon Warning Light illuminates, indicating a potential issue with the engine coolant temperature sensor circuit.
- Poor Fuel Economy: The vehicle may experience reduced fuel efficiency due to incorrect temperature readings affecting fuel mixture adjustments.
- Engine Overheating: The engine may overheat as the cooling system may not function optimally without accurate temperature data.
- Hard Starting: Difficulty in starting the engine, especially in cold conditions, due to incorrect temperature readings affecting fuel delivery.
- Erratic Temperature Gauge: The temperature gauge may display erratic or incorrect readings, indicating a malfunction in the sensor circuit.
What causes OBD code Error Code P0118?
- The engine coolant level may be low, leading to inaccurate temperature readings.
- A faulty engine coolant thermostat can cause the engine to run at incorrect temperatures.
- The engine coolant temperature (ECT) sensor might be malfunctioning, providing incorrect data to the ECM.
- The ECT sensor harness could be open or shorted, disrupting the signal transmission.
- Poor electrical connections in the ECT sensor circuit can lead to intermittent or incorrect signals.
- The engine control module (ECM) may be faulty, misinterpreting the sensor data.
How to fix OBD code Error Code P0118?
- Initial Inspection: Check the engine coolant level at the coolant reservoir. A low level may indicate a coolant leak, which should be addressed before further diagnostics.
- Visual Inspection of ECT Sensor: Inspect the Engine Coolant Temperature (ECT) sensor and its wiring for any visible damage, corrosion, or loose connections.
- Test ECT Sensor: Use a multimeter to measure the resistance of the ECT sensor. Compare the readings with the manufacturer's specifications to determine if the sensor is faulty.
- Check ECT Sensor Circuit: Inspect the ECT sensor circuit for any open or short circuits. Ensure the wiring harness is intact and properly connected.
- Replace ECT Sensor: If the ECT sensor is found to be faulty, replace it with a new one. Ensure the new sensor is properly installed and connected.
- Replace Engine Coolant Thermostat: Replace the engine coolant thermostat as part of the repair process to ensure proper functioning of the coolant system.
- Clear DTC and Test Drive: Clear the DTC code from the vehicle's computer and perform a test drive to ensure the issue is resolved and the code does not reappear.