Check several fault codes at once
Paste or type every code your scan tool shows. You get what each one means and what it does, grouped by system.
Reading several codes together
- Start with network (U) codes: a module that stops communicating can set codes in the systems that depend on it.
- Low battery voltage or a poor ground can set many unrelated codes at once. Check the battery, charging and grounds first.
- Codes that point at the same thing, such as lean on both banks (P0171 and P0174), usually share one cause, such as an air leak or low fuel pressure.
- After a repair, clear the codes and drive: a code that returns shows the fault is still there.