P2180: System Too Rich Off Idle Bank 2
What to do
Expect poorer fuel economy and possibly a fuel smell. Check whether bank 1 is also rich — if it is, the cause is shared and cheaper to find. On a direct-injection engine, do not leave a persistent rich condition unrepaired: fuel works past the rings into the oil and thins it, which is an engine problem rather than an emissions one.
What this code means
The off-idle rich condition of P2178, on the second cylinder bank. The one-bank-or-both narrowing set out at P2179 applies unchanged and should be the first question asked.
One cause is specific to a single bank and worth naming, because it produces a rich reading without any excess fuel existing: a leaking injector on that bank. Fuel entering a cylinder outside the injection event is fuel the module did not account for, and it reaches only the sensor watching that bank. On a direct-injection engine this also dilutes the oil with fuel over time, which is a consequence well beyond the mixture reading and a reason not to leave it.
Likely causes
Start here
- Leaking fuel injector · moderate
- Faulty oxygen sensor · moderate
Less common
- Faulty EVAP purge valve · easy
- Excessive fuel pressure · moderate
- Faulty mass air flow sensor · easy
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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