Engine Coolant Temperature (ECT) Sensor 1

The engine coolant temperature sensor measures how hot the coolant is. If it's reading too high or too low, the computer thinks something's wrong with cooling.

The engine computer monitors the ECT sensor voltage, which should be proportional to coolant temperature. It expects a range of 0.5 to 4.5 volts corresponding to 0°C to 120°C (32°F to 248°F).

Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.

1. 11. Check the connector and wiring for damage or corrosion. Repair if necessary. Decision point: Is the wiring intact? (YES/NO)
2. 22. Inspect the coolant level in the reservoir. Top off if low. Decision point: Is coolant level adequate? (YES/NO)
3. 33. Use a scan tool to monitor the ECT sensor reading. Compare with actual coolant temperature using an infrared thermometer. Decision point: Are values within expected range? (YES/NO)
4. 44. If ECT reading is out of range, replace the ECT sensor. Decision point: Is the code cleared after replacement? (YES/NO)
5. 55. If the code returns, check for wiring issues again or inspect the engine control module.

• Faulty ECT sensor
• Wiring issues or damaged connectors
• Low coolant level

$$