Engine Coolant Temperature (ECT) Sensor - Voltage Above Normal
The engine coolant temperature sensor is reading a voltage that is higher than expected.
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 should tell the computer how hot the engine coolant is. When it shows too high a voltage, the computer thinks it’s wrong and that could affect engine performance and emissions.
What the computer is actually seeing
The engine control module (ECM) expects a reading from the ECT sensor between 0.5V (cold) to 4.5V (hot) in standard conditions. A voltage above 4.5V indicates an issue with the sensor or its circuit.
What a healthy reading looks like
Normal operation should see 0.5 to 4.5 volts depending on the coolant temperature; above 4.5V triggers this code.
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 the wiring harness and connectors for damage or corrosion before testing anything.
- 2Measure the voltage at the ECT sensor connector. If it’s above 4.5V, look for short circuits in the wiring.
- 3If the voltage is within the expected range, check the resistance of the ECT sensor. A normal reading at room temp (about 70°F/21°C) should be around 2.5 to 3.5k ohms.
- 4If resistance is off, replace the sensor and retest. If it's good, inspect the ECM for faults.
Common causes
- Faulty coolant temperature sensor
- Wiring or connector issues
- Short circuit to power in sensor circuit
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's generally drivable, but fix it soon to avoid poor fuel economy and emissions.
Will the code come back after resetting?
If the issue isn't addressed, it likely will return.
Why does this code pair with SPN 110?
SPN 110 indicates a coolant temperature issue as well; they often trigger together.
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 →