P2189

P2189 is the bank 2 mirror of P2188 — the fuel system on bank 2 runs lean AT IDLE specifically, with STFT + LTFT pinned above +15% at warm idle and trims returning to ±5% the moment the throttle cracks open. Because the code is bank-specific and idle-only, the diagnostic narrows fast: anything that affects both banks globally (low fuel pressure, dirty MAF, weak pump) typically throws P2188 AND P2189 together, so a solo P2189 points at a vacuum leak or intake fault mechanically isolated to the bank 2 side. Cheapest-first: smoke-test the bank 2 intake runners, the bank 2 PCV breather path (many V-engines route the PCV to one bank and a fresh-air breather to the other), the bank 2 intake-manifold gasket, and any rubber elbows on that bank. Check for exhaust leaks ahead of the bank 2 upstream O2 sensor — a crack at the manifold flange pulls atmospheric oxygen into the sensor's reading and fakes a lean condition. Compare bank 1 vs. bank 2 STFT at idle: bank 1 at +3% with bank 2 at +22% is the photograph of a bank-2-only mechanical leak. The at-idle code is the giveaway — don't condemn the O2 sensor; the sensor is correctly reporting that bank 2 sees more air than fuel at idle. Find the bank-2 unmetered air source.

Vehicle-specific patterns: 2007-2014 Ford F-150 / Expedition / Navigator with the 5.4L 3-valve Triton V8 throws P2189 alone from a cracked composite intake manifold on the passenger (bank 2) side near the EGR port — Ford issued multiple TSBs and the upgraded composite-plus-aluminum manifold is the durable fix ($350-$500 part, $700-$1,100 installed). 2005-2010 Chrysler 300 / Charger / Magnum 3.5L V6 throws P2189 from cracked rear-bank intake-manifold plenum gaskets. 2008-2014 BMW N63 twin-turbo V8 (550i, 750i, X5/X6 5.0i) throws P2189 from bank-2 intake-side oil-separator failure and from cracked intake boots between the turbos and the intake manifold. 2006-2012 GM 5.3L Vortec V8 (Silverado, Tahoe, Suburban) throws P2189 from a torn bank-2-side intake gasket and from a failing PCV fixed-orifice on the valley cover. Estimated repair: $90 to $1,100.