Engine Coolant Temperature Sensor B Circuit High
The signal from the Engine Coolant Temperature (ECT) Sensor B is too high.
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What it means (plain English)
The engine computer gets a temperature reading from a sensor in the cooling system that says the coolant is hotter than it should be, which can interfere with engine performance.
What the computer is actually seeing
The engine control module (ECM) sees a voltage signal from the ECT Sensor B that is above 4.0 volts, indicating an excessively high temperature.
What a healthy reading looks like
ECT Sensor B should output a voltage between 0.5 to 4.5 volts; 0.5V typically indicates -40°C (-40°F) and 4.5V indicates 140°C (284°F).
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. Inspect the wiring and connector to ECT Sensor B for damage or corrosion. Fix if necessary.
- 22. Check the coolant level; ensure it is within the appropriate range. Top off if low.
- 33. Measure the voltage output of ECT Sensor B with a multimeter at idle. Should be between 0.5V and 4.5V. If not, replace the sensor.
- 44. If ECT Sensor B voltage is normal, check for short circuits or grounds in the wiring harness while performing a continuity test.
- 55. Clear the code from the ECM and perform a road test. If the code returns, further investigate ECM functionality.
Common causes
- Faulty ECT Sensor B
- Wiring issues or shorts in the sensor circuit
- Bad connector at the ECT Sensor B
- Coolant overflow or contamination
- Faulty ECM processing the signal
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's moderate severity; you can drive but watch for engine overheating.
What happens if I ignore this code?
Ignoring it can lead to engine performance issues or damage due to overheating.
Why does this code occur with other sensor codes?
It often pairs with other ECT sensor codes indicating potential systemic coolant issues.
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