What causes a P2178 code?

Common causes: Leaking injector; High fuel pressure; Failed O2 sensor; PCV stuck open.

What are the symptoms of a P2178 code?

Typical symptoms: CEL; Black smoke; Fuel smell; Poor MPG.

Yes — this code is generally safe to drive with, but address it soon to avoid escalation. Estimated repair: $80-$600.

OBD-II Code · Powertrain

System Too Rich Off Idle (Bank 1)

medium severitySafe to drive$80-$600

Long-term fuel trim showing rich condition off-idle on bank 1.

Common symptoms

Likely causes

Where to start

Try the cheapest cause first. Start by checking: leaking injector.
Cost & scope. $80-$600
If the code returns after the fix: escalate to a shop or scanner with live-data and freeze-frame. A code that re-sets means the underlying fault is still there.

Look up another code

More free tools