Fault in the Engine Coolant Temperature Sensor (ECT)
This indicates a problem with the engine coolant temperature sensor 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 engine coolant temperature sensor measures the temperature of the coolant, which helps manage engine performance. If it fails, the engine may run poorly or overheat because the computer can’t make the right adjustments.
What the computer is actually seeing
The ECM expects the ECT to report a temperature that correlates with the actual engine coolant temperature, typically between 180°F and 220°F (82°C to 104°C).
What a healthy reading looks like
Expected values from a normal ECT sensor range from 0.5V (cold) to 4.5V (hot), corresponding to coolant temperatures of roughly 32°F to 240°F (0°C to 115°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.
- 11. Check the coolant level. Ensure it is at the proper level in the system. If low, top it off and see if the code returns.
- 22. Inspect the wiring and connectors for the ECT sensor. Look for signs of damage, corrosion, or poor connections. Fix any issues found before further testing.
- 33. Use a scan tool to monitor the ECT readings while the engine is running. Compare the values to the expected normal range of 180°F to 220°F (82°C to 104°C).
- 44. If the ECT sensor readings are out of range, voltages are incorrect, or if the wiring is good, replace the ECT sensor and clear the code.
Common causes
- Faulty coolant temperature sensor
- Wiring issues (broken, shorted, or corroded connectors)
- Coolant level too low
- ECM software issues
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It’s moderate severity, so you can drive but should address it soon to avoid overheating and performance issues.
Will this code come back after repairs?
If correct procedures are followed and the faulty components are replaced, it should not return.
Why does this code sometimes pair with SPN 133?
SPN 133 is often related to an out-of-range signal, typically due to similar faults in the coolant temperature sensor circuit.
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