Engine Coolant Temperature Circuit Intermittent
There's a problem with the engine coolant temperature sensor circuit.
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 computer is getting crazy readings from the coolant temperature sensor, like if it suddenly goes from 200°F to -40°F without any real change in temperature.
What the computer is actually seeing
The PCM (Powertrain Control Module) expects a consistent voltage signal from the coolant temperature sensor that typically ranges from about 0.5V to 4.5V based on temperature. If it sees unexpected jumps or drops, it triggers this code.
What a healthy reading looks like
Coolant temperature sensor voltage should be around 0.5V at -40°F and about 4.5V at 250°F. Look for gradual changes corresponding to the actual temperature.
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 connector and wiring for the coolant temp sensor. Look for corrosion, breaks, or loose connections. If found, repair/replace as necessary.
- 2Using a scan tool, monitor the live data for the coolant temperature while the engine runs. Is the reading fluctuating erratically? If yes, the sensor is likely faulty.
- 3Test the resistance of the coolant temperature sensor with a multimeter. At ambient temperature, it should read about 2.5k ohms at 70°F. Is it out of range? If yes, replace the sensor.
- 4Check the ground circuit to the sensor. Use a multimeter to measure voltage drop. Should be less than 0.1V. If excessive, repair grounds.
Common causes
- Faulty coolant temperature sensor
- Damaged wiring or connectors in the circuit
- Poor ground connection to the sensor
- ECM/PCM issues
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's drivable but monitor the temperature gauge closely. If it overheats, pull over immediately.
Will the check engine light go off on its own?
Not likely. You need to fix the issue for the light to reset.
Why might this code pair with other codes?
Poor electrical connections can cause multiple sensors to behave erratically, triggering several codes.
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