Multi-code OBD2 diagnosis
Enter all the codes your scanner showed, not just the first one. We give you the overall severity, whether you can keep driving, the order in which to check them and how they relate to each other.
Summary
- Overall severity
- Low
- Can I keep driving?
- Yes, no immediate risk
- Estimated cost
- $40 to $400
- Codes analyzed
- 1 of 1
The order below is the recommended one: first the codes that can cause the others. After each repair, clear the codes and check which ones come back.
Order of inspection
P0640 Intake Air Heater "A" Control Circuit Low
The P0640 code means there is a fault in the circuit the computer uses to control the intake air heater on a diesel engine. The engine starts harder when cold. The usual culprit is a bad heater relay.