P0640 OBD II Trouble Code Intake Air Heater Control Circuit
How to easily diagnose, repair, and info on causes of a P0640 trouble code that indicates a detected failure of the intake air heater control circuit.
Symptoms of P0640 OBD II Trouble Code
- Diminished fuel efficiency
- Rough idle on cold start
- Drivability issues when cold
- Other IAT codes
Common Causes of P0640 OBD II Trouble Code
- Defective or disconnected intake air temperature sensor
- Faulty intake air heater relay or fuse
- Shorted or open wiring or connectors
- Burnt out intake air heater element
- Bad PCM or programming error
Severity of P0640 OBD II Trouble Code
Intake air temperature codes should be classified as severe and addressed as such. A code P0640 may be accompanied by various drivability symptoms, especially when the engine is cold.