P2BF2 — Fuel Control System B Too Lean Bank 2

Diagnostic algorithm

1. Retrieve and save freeze frame, all active and pending codes. Note conditions when the code set (RPM, load, temp).
2. Visual inspection: check intake boots, vacuum hoses, PCV, EVAP lines, and intake manifold gasket area on bank 2 for leaks or damage.
3. Scan tool live data: observe STFT and LTFT for bank 2, compare to bank 1. Monitor bank 2 O2/wideband behavior and MAF values at idle and during acceleration.
4. Perform a smoke/leak test on the intake and vacuum system focused on bank 2; repair any leaks and retest.
5. Measure fuel rail pressure at key on/idle/under load; compare to spec. If low, inspect fuel pump, filter, regulator.
6. Inspect and test injectors on bank 2: electrical resistance, back‑probing pulse width, and perform a balance flow test or use a noid light where appropriate.
7. Clean or test the MAF sensor; if readings are inconsistent or contaminated, try replacement or bench test per manufacturer data.
8. Inspect exhaust upstream of the bank 2 O2 sensor for leaks; repair and retest sensor readings.
9. If sensor/wiring suspected, backprobe and wiggle test connectors; check for shorts/opens and proper ground. Replace or swap O2/wideband sensor with known good unit if needed to verify.
10. After repairs, erase codes and perform a test drive under the original freeze‑frame conditions to confirm the code does not return.
11. If all mechanical and sensor checks pass, consider ECM software update or module diagnosis as a last resort.