Coolant Temperature Sensor Voltage Above Normal
Coolant temperature sensor is reporting a voltage that's too high.
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 coolant temperature sensor is sending a voltage reading above what the computer expects, which can mean it's malfunctioning or there's an electrical issue.
What the computer is actually seeing
The engine control module (ECM) expects the coolant temperature sensor to output between 0.5V to 4.5V, corresponding to temperatures from -40°C to 130°C (-40°F to 266°F). If it sees a reading above 4.5V, it triggers this fault.
What a healthy reading looks like
Coolant temperature sensor should output between 0.5V (low coolant temp) to 4.5V (high coolant temp).
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 wiring and connector at the coolant temperature sensor for any signs of damage or corrosion. Repair as necessary. Decision Point: Is the wiring intact? Yes: Proceed to step 2. No: Repair wiring and retest.
- 22. Measure the voltage output of the coolant temperature sensor with a multimeter while the engine is running. Expected output is between 0.5V and 4.5V. Decision Point: Is the voltage within expected range? Yes: Proceed to step 3. No: Replace the coolant temperature sensor.
- 33. Inspect the ECM for any possible faults or poor connections. If the ECM has water damage or corrosion, consider replacing it or repairing connections. Decision Point: Is the ECM functioning properly? Yes: Investigate further issues. No: Replace the ECM.
Common causes
- Faulty coolant temperature sensor
- Wiring issues (short to power)
- Corrosion or bad connector at the sensor
- ECM calibration error
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's safe to drive temporarily, but keep a close eye on engine performance and temperature.
Will this code come back after clearing?
If the underlying issue isn't resolved, yes, the code will likely return.
What happens if the sensor is faulty?
A faulty sensor can cause poor engine performance, increased emissions, and overheating risk.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
Start guided diagnostic →