Engine Coolant Temperature Sensor Out of Range
Coolant temperature sensor is reporting an incorrect value.
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What it means (plain English)
The engine's computer uses the coolant temperature sensor to check if the engine is getting too hot; if it gets a number outside expected range, it throws this code.
What the computer is actually seeing
The coolant temperature sensor sends a voltage signal between 0.5 volts (cold) to 4.5 volts (hot). If the signal is outside 0.7-4.0 volts unexpectedly, the computer triggers this code.
What a healthy reading looks like
0.7 to 4.0 volts from the coolant temperature sensor under normal operating conditions.
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.
- 1Inspect wiring and connector for damage or corrosion before anything else.
- 2Check coolant level; a low level can affect sensor operation.
- 3Use a multimeter to measure the voltage at the coolant temperature sensor; expect 0.7-4.0 volts. If not, go to the next step.
- 4With the engine at operating temperature, verify the temperature reading on your scan tool against a known good temperature using a thermometer. If readings are off, replace the sensor.
- 5If sensor readings match but the code persists, inspect the wiring for shorts to ground or power.
Common causes
- Failed coolant temperature sensor
- Wiring issues (shorts or opens) in the sensor circuit
- Corroded connectors
- Coolant leaks affecting sensor operation
Typical repair cost
$$
Related codes
Frequently asked questions
Can I drive with this code?
Yes, but fix it soon to avoid possible engine overheating and damage.
Will the code come back after reset?
If the underlying issue isn’t fixed, it likely will.
Why does this code sometimes appear with SPN 0198?
SPN 0198 indicates a related circuit range issue, often caused by the same sensor problems.
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