What Does P008F Mean?
The ECM has determined that the engine coolant temperature (ECT) sensor and fuel temperature sensor readings do not correlate properly during a cold start or soak period. When the engine has been off long enough to reach ambient temperature, both sensors should read approximately the same value. A significant discrepancy suggests one of the sensors is reading inaccurately. The driver may notice poor cold-start performance, incorrect fuel trim, or the check engine light.
Common Causes
30%
Faulty engine coolant temperature sensor reading incorrectly
30%
Faulty fuel temperature sensor reading incorrectly
20%
Wiring issue causing incorrect reading on one of the temperature circuits
12%
Thermostat stuck partially open causing ECT to read lower than expected on a cold start
8%
ECM internal reference voltage error affecting one sensor circuit
Diagnostic Steps
1
On a cold engine (overnight soak), compare the ECT and fuel temperature PIDs before starting. Both should be within 5-10 degrees of ambient temperature. Identify which sensor is reading incorrectly.
2
Using an infrared thermometer, verify the actual coolant temperature and fuel line temperature against the sensor PID readings. This isolates which sensor is inaccurate.
3
Check the ECT sensor resistance and compare to the manufacturer's temperature-resistance chart. Typical values: ~5,000 ohms at 32F (0C), ~2,000 ohms at 68F (20C), ~300 ohms at 176F (80C).
4
Check the fuel temperature sensor resistance against its spec chart. Even small deviations can trigger this correlation code.
5
Inspect both sensor connectors for corrosion, pushed-back pins, or water intrusion. Verify the 5V reference and ground signals at each connector.
Estimated Repair Cost
$75 - $350
Parts + labor, varies by vehicle and location
The ECM has determined that the engine coolant temperature (ECT) sensor and fuel temperature sensor readings do not correlate properly during a cold start or soak period. When the engine has been off long enough to reach ambient temperature, both sensors should read approximately the same value. A s...
The most common cause of P008F (Engine Coolant Temperature/Fuel Temperature Correlation) is: Faulty engine coolant temperature sensor reading incorrectly
Typical repair costs for P008F range from $75 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive. The ECM may use substitute values for fuel delivery calculations, which can affect fuel economy and cold-start quality. No immediate safety risk but inaccurate temperature readings can lead to improper fuel trim and increased emissions over time.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P008F to identify the root cause.
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Quick Info
Category
Powertrain
System
Engine Management / Sensor System
Difficulty
Type
Generic (SAE)
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