Engine Coolant Temperature Sensor No Data
ECM is not receiving a temperature signal from the coolant sensor.
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What it means (plain English)
The engine control module (ECM) is supposed to get a temperature reading from the coolant sensor to know how hot the engine is. If it doesn’t get any data, it can’t manage the engine’s performance and fuel efficiency properly.
What the computer is actually seeing
The ECM expects a voltage signal between 0.5V and 4.5V depending on the coolant temperature. With a failure, the ECM sees either no signal or an open circuit.
What a healthy reading looks like
Coolant temperatures typically range from 190°F to 220°F (88°C to 104°C) with corresponding sensor voltages between 0.5V (cold) and 4.5V (hot).
Guided diagnostic — the DiagCoach way
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.
- 11. Check the coolant level – it should be at the proper fill line. If low, top it off and recheck for the code.
- 22. Inspect the wiring and connector to the coolant temperature sensor for damage, corrosion, or loose connections. Repair as necessary.
- 33. Using a multimeter, test the coolant temperature sensor. At room temperature, you should see a voltage reading close to 2.5V. If not, replace the sensor.
- 44. If the sensor is fine, use a scan tool to check for any other active fault codes related to the engine management system.
- 55. If no other codes are present, check the signal wire from the sensor to the ECM for continuity and shorts. Repair if needed. If all checks out, consider testing or replacing the ECM.
Common causes
- Faulty coolant temperature sensor
- Broken wiring or poor connections
- Failed ECM
- Coolant leaks affecting sensor operation
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not safe to drive as the engine may overheat or run inefficiently without the temperature data.
Will this code come back even after repairs?
If the sensor and wiring are properly repaired, the code should not return.
Why does this code pair with SPN 111?
SPN 111 indicates Engine Coolant Temperature Sensor circuit failures, which is directly related to the absence of data from the sensor.
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