338 Engine coolant temperature lower than expected
How to read it
Code 338 reads as 3 flashes, pause, 3 flashes, pause, 8 flashes on the check-engine light. Jumper the self-test input to signal return at the test connector, then run the key on engine off self test and the running self test, counting the check-engine flashes each time.
New to flash codes? The OBD-I code reading guide walks through the paperclip method, code 12, and reading two-digit codes.
What does Ford code 338 mean?
338. Engine coolant temperature lower than expected. This code sets when your vehicle computer detects engine coolant temperature lower than expected.
Common causes of 338
- Vacuum or intake leak
- Low fuel pressure or a clogged fuel filter
- Faulty engine coolant temperature sensor
- Open or shorted wiring or a bad connector in the circuit
- Dirty or weak fuel injectors
How to fix 338
- Confirm the code and read the flash sequence again
- Check for vacuum and intake leaks
- Inspect the engine coolant temperature sensor and its connector for damage and corrosion
- Measure fuel pressure and check the fuel filter
- Replace the engine coolant temperature sensor or a failed part only after the tests