Engine Coolant Temperature/Fuel Temperature Correlation
What it means
P008F means the engine coolant temperature reading and the fuel temperature reading disagree by more than the ECM allows. After the engine has sat overnight these two temperatures should be nearly the same, so a mismatch usually points to a faulty sensor, a wiring fault, or a real cooling problem such as low coolant or a stuck thermostat. The car normally still drives, but wrong temperature data can hurt cold-start fueling and economy.
Can I keep driving? Usually driveable, but a wrong temperature reading can upset cold-start fueling and cooling-fan control, so repair it promptly.
Common symptoms
What you'll notice
- Check-engine light on
- Hard cold starts or rough running when cold
- Poor fuel economy
- Cooling fans or temperature gauge behaving oddly
Common causes
Most likely first
- Faulty engine coolant temperature (ECT) sensorLikely
- Faulty fuel temperature sensorCommon
- Low coolant level or a stuck thermostat skewing actual coolant temperatureCommon
- Wiring or connector fault on either temperature sensor circuitLess often
- Failed ECM (least likely)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and compare the coolant and fuel temperature readings on a scan tool — after a cold soak they should be close.
- Check coolant level and thermostat operation; a stuck thermostat can make the readings disagree.
- Inspect both sensors' connectors and wiring, and confirm a steady 5-volt reference and good ground.
- Replace whichever sensor reads inaccurately; consider the ECM only last. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P008F?+
Can I just clear P008F?+
Related codes
Often seen with P008F
Read & clear P008F yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.