Engine Coolant Temperature Sensor 1
The Engine Coolant Temperature (ECT) sensor has detected an abnormal temperature reading.
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 ECT sensor measures how hot the engine coolant is. If it's too high or low, the engine control module (ECM) thinks there's a problem, so it triggers this code.
What the computer is actually seeing
The engine control module receives voltage signals from the ECT sensor. It expects the voltage to be between 0.5V (for -40°C) and 4.5V (for 150°C). If the reading goes beyond this range, you'll get this code.
What a healthy reading looks like
0.5V to 4.5V corresponds to -40°C to 150°C; normal operating range around 0.9V to 1.5V (around 80°C to 90°C).
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 coolant level — ensure it's within the normal range. If it's low, top it off and retest.
- 2Inspect the ECT sensor wiring and connector for damage or corrosion. Repair as necessary.
- 3Using a multimeter, measure the voltage at the ECT sensor connector. Expect readings between 0.5V and 4.5V under normal conditions.
- 4If voltage readings are out of range, replace the ECT sensor. If the reading is normal, suspect the ECM may be faulty.
Common causes
- Faulty ECT sensor
- Wiring issues (shorts, open circuits)
- Faulty ECM
- Coolant leaks affecting sensor operation
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Moderate severity means you can drive, but don't ignore the issue. It may affect emissions and engine performance.
Will this code come back after clearing?
If the issue is not fixed, the code will likely return after a short period.
Why does this code pair with other codes?
Multiple codes often indicate related problems, especially in temperature sensors or engine management systems.
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