The same lean-mixture problem as P0171, but affecting bank 2 (the other cylinder bank on a V6/V8/V-configuration engine) rather than bank 1. On an inline engine, banks 1 and 2 don't apply the same way, so seeing this code specifically confirms a V-type or flat engine layout.
Symptoms
- Rough idle or a slight surge at idle
- Hesitation or reduced power under acceleration
- Occasional misfire on bank 2 cylinders specifically
- Often appears alongside P0171 if the cause is something shared, like a MAF sensor issue
Likely causes
- Vacuum leak on the bank 2 side of the intake
- A dirty or failing mass airflow (MAF) sensor — since this sensor affects the whole engine, it often causes both banks to trigger lean codes together
- Weak fuel pressure affecting bank 2's injectors more than bank 1's, depending on fuel rail design
- A clogged or underperforming injector on one of the bank 2 cylinders
How to diagnose it
- Check fuel trim values for both banks with a scan tool — if both banks show similar lean trims, suspect a shared cause like the MAF sensor; if only bank 2 is affected, focus there specifically
- Inspect bank 2 intake hoses and gaskets for leaks
- Check fuel pressure at the rail against spec
Typical fixes & cost
- Repair a vacuum leak on the bank 2 intake50–250 EUR
- Clean or replace the MAF sensor60–220 EUR
- Replace fuel filter, or fuel pump if pressure is confirmed low150–600 EUR
Code names are compiled from open/standardized SAE and ISO references. Explanations, symptoms, causes and fixes are original. Covers generic (P0/C0/B0/U0) codes only — manufacturer-specific codes are planned for a future update.
AS
Reviewed by Artyom SemenovAutomotive Editor · Fact-checked by Yauheni Kapliarchuk, Editor-in-Chief