Engine Coolant Temperature Sensor Fault
The engine coolant temperature sensor is reporting an out-of-range value.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The engine's computer uses the coolant temperature sensor to check how hot the engine is running. If the sensor reads way too high or too low than normal, it sets this fault.
What the computer is actually seeing
The engine control module (ECM) sees abnormal resistance or voltage from the coolant temperature sensor, typically above 230°F (110°C) or below 32°F (0°C) continuously over a certain period.
What a healthy reading looks like
Normal coolant temperature values should range between 160°F (71°C) and 220°F (104°C).
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.
- 1Check the wiring and connector for the coolant temperature sensor. Look for frayed wires, corrosion, or loose connections. If they are damaged, repair or replace them before continuing.
- 2Measure the voltage at the coolant temperature sensor connector with the key on, engine off. You should see around 5V. If there's no voltage, trace the wiring back to the ECM and check for continuity and shorts.
- 3With the engine running at normal operating temperature, use a scan tool to monitor the coolant temperature reading. It should match your gauge and be within the expected range of 160°F to 220°F. If it's off, the sensor is likely faulty and should be replaced.
- 4Check engine coolant level. If it's low, top it off and recheck sensor function. Low coolant can affect sensor reading accuracy.
Common causes
- Damaged or corroded wiring to the coolant temperature sensor
- Faulty coolant temperature sensor
- Coolant leaks affecting sensor exposure
- Inaccurate ECM calibration software
Typical repair cost
$$
Related codes
Frequently asked questions
Can I drive the vehicle with this code?
Yes, but the engine may run poorly or could overheat if the coolant temperature is not read accurately.
Will this fault come back after I fix it?
If the issue is resolved at the wiring or sensor level, the code should not return. However, if there's an underlying problem, it might reappear.
Why does this code sometimes pair with other codes?
Multiple codes can indicate that the coolant temperature is affecting other engine functions, like fuel delivery or emissions control.
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