Too much fuel or too little air on bank 2 — mirror of P0172 for the second bank.
Common symptoms
- Rough idle
- Black exhaust smoke
- Poor fuel economy
Typical causes
- Leaking injector bank 2
- Failed MAF
- High fuel pressure
- Faulty bank 2 O2 sensor
What scanner do you need?
Enhanced OBD2 scanner (live data graphs, freeze frame, battery voltage test)
Use live data and freeze frame to confirm the fault before replacing parts. ABS, SRS, and network U-codes usually require a full-system scanner.
Diagnostic tips
- Record freeze frame data when the code first sets
- Clear the code only after fixing the root cause
- Check for related pending codes that point to a common issue
- Verify battery voltage is above 12.4V before chasing sensor codes