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
- $100 to $1,200
- 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
P0491 Secondary Air Injection System Insufficient Flow (Bank 1) Low
The P0491 code means not enough secondary air is reaching bank 1. The computer detects it because the oxygen sensor on that bank does not go lean when the pump is turned on. There are usually no driving symptoms, but the vehicle will not pass an emissions test while the code is set.