P219B: Bank 2 Air-Fuel Ratio Imbalance

What does P219B mean?

P219B is the bank 2 counterpart for V and boxer engines. Ford's 2012 summary shows one way to find it: the ECM watches the fast ripple of the bank's wide-band sensor over windows of roughly 50 revolutions and sets the code when more than 75 % of them fail, after 300 to 700 s of driving at 1000 to 3000 rpm and 20 to 60 % load. On one GM 2016 engine the bank 2 limit is 1.15 against 1.05 for bank 1. Bulletins name leaking direct injectors (Ford F-150 2.7 EcoBoost 2018; Explorer and Aviator 3.0 EcoBoost 2023 to 2025, injectors of the affected bank replaced), faulty or contaminated injectors (Honda Pilot 2016), electrical noise in the A/F sensor lines (Mazda CX-9 2011 to 2013) and, at Infiniti on the QX80, a warning not to swap the A/F sensor first. A code on bank 2 only points to a part on that side.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light on
• Usually no driveability change
• Possible misfire codes on bank 2 cylinders

Common causes

• High Leaking or contaminated injector on bank 2
• Medium Interference or damage in the bank 2 A/F sensor wiring
• Medium Intake runner or gasket leak at one bank 2 cylinder
• Low PCM calibration addressed by a software update

Likelihood is a general estimate across vehicles; your make and model may differ.