Missing Engine Temperature Data
The Engine Control Module (ECM) isn't receiving temperature data from the engine coolant temperature (ECT) sensor.
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What it means (plain English)
The computer uses the ECT sensor to know the engine temperature. When it doesn't get this info, it can't adjust fuel mixture or timing properly.
What the computer is actually seeing
The ECM expects a changing voltage from the ECT sensor based on coolant temperature, typically between 0.5V at -40°C to 4.5V at 150°C.
What a healthy reading looks like
Look for 0.5V to 4.5V from the ECT sensor corresponding to temperatures -40°C to +150°C. If values don't change or are outside this range, there's an issue.
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 ECT sensor connector for corrosion or damage.
- 2Inspect the wiring for breaks or shorts.
- 3Using a multimeter, check the output voltage from the ECT sensor at various engine temperatures; it should vary between 0.5V and 4.5V.
- 4If voltage is fixed or out of range, replace the ECT sensor.
- 5If the sensor is fine, check for continuity issues in the wiring to the ECM.
Common causes
- Faulty engine coolant temperature sensor
- Wiring issue or damaged connector
- ECM malfunction
- Recent engine work affecting sensor placement
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this fault code?
It's best to fix it soon, but you can drive short distances; just expect possible drivability issues.
Will this code come back after repairs?
If you address the root cause, it shouldn't return.
Does it pair with other codes?
Yes, common related codes often indicate similar sensor issues.
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