P008F: Engine Coolant Temperature/Fuel Temperature Correlation Fault
Check engine light illuminated; potential rough idle, reduced fuel economy, and poor engine performance
Overview
P008F is an OBD‑II generic powertrain code indicating the PCM has detected an implausible correlation between engine coolant temperature and fuel temperature sensor readings, often caused by sensor faults, wiring issues, or PCM calibration errors.
Common Symptoms
- Check engine light illuminated
- Reduced engine performance
- Decreased fuel efficiency
- Rough idle or hesitation
- Possible hard starting or overheating indications
Most Common Causes
Incorrect coolant temp reading can trigger correlation fault.
Incorrect fuel temp reading causes mismatch with coolant data.
Corrosion, damage, opens, or shorts can distort signals.
Less common; consider after sensors and wiring are confirmed good.
Diagnostic Steps
-
Use a diagnostic scanner to confirm P008F and note any other related codesExpected: P008F present with or without other temp or sensor codesInterpretation: Confirms code and provides context for additional diagnostics
-
Visual inspection of ECT and fuel temperature sensor wiring and connectorsExpected: No damaged, corroded, or loose connectorsInterpretation: If issues found, likely cause; if not, proceed deeper
-
Compare live data readings of coolant and fuel temperatures via scan toolExpected: Readings should correlate within expected ranges during warm‑upInterpretation: Discrepancies help identify which sensor or circuit is suspect
-
Test individual sensors with a multimeter (resistance or voltage per OEM specs)Expected: Sensor outputs match specification tablesInterpretation: Out‑of‑spec sensor should be replaced
-
Check reference voltage (typically 5V) and ground at sensor harness with key on engine offExpected: Stable reference voltage and good ground presentInterpretation: Lack of proper reference/ground indicates wiring/ECM issue
Repair Solutions
Common and effective if ECT sensor is failing
Often integrated into fuel system; costs vary by vehicle
Depends on extent of wiring damage
Requires OEM‑level diagnostic tools
Common Misdiagnoses
Avoid these common diagnostic mistakes:
- Assuming the ECT sensor is always faulty without testing fuel temperature sensor
- Replacing sensors without checking wiring/connectors first
- Ignoring ECM calibration/TSB updates that may affect correlation logic
User Comments (0)
Share your experience or ask a question about this code.
Please login to post a comment.
Be the first to share your experience with P008F!