Engine Coolant Temperature Sensor Circuit High
Engine coolant temperature sensor is reporting high signal voltage.
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 coolant temperature sensor is sending a voltage reading higher than normal, usually above 4.5 volts, which indicates it's likely faulty or there's a wiring issue.
What the computer is actually seeing
The engine control module (ECM) is monitoring the coolant temperature sensor output voltage. A voltage above 4.5 volts usually indicates an open circuit (sensor failure) or short to power.
What a healthy reading looks like
Normal voltage from the coolant temperature sensor should be between 0.5 to 4.5 volts depending on the coolant temperature (around 195°F should be approximately 2.5 volts).
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 on the coolant temperature sensor for damage or corrosion.
- 2Test the voltage at the coolant temperature sensor connector; it should read between 0.5 and 4.5 volts with the engine running.
- 3If voltage is above 4.5 volts, the sensor is likely faulty; replace the coolant temperature sensor.
- 4If the wiring was found damaged, repair or replace it, then retest the system.
Common causes
- Faulty coolant temperature sensor
- Wiring issues (short to power or open circuit)
- Poor connection at the sensor or ECM
- Corroded terminals or connectors
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
It’s advisable to fix it soon since it can lead to improper engine temperatures, affecting performance.
Will this code clear by itself?
Not usually; it will persist until the fault is corrected and the code is cleared.
Why would it pair with another code?
Multiple codes can trigger if multiple sensors are affected or related issues are present in the same circuit.
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 →