P219B⛽ Fuel / air metering (cylinder air-fuel balance, Bank 2)Stop and fix promptly

P219B: Bank 2 Air/Fuel Ratio Imbalance (Meaning, Causes, Fixes)

Reviewed 2026-10-23 · Based on 3 cited source(s)

What P219B means

The powertrain control module (PCM) watches the upstream oxygen or air-fuel ratio (A/F) sensor on each bank to judge how rich or lean the engine is running. Bank 2 is the side of a V6 or V8 that does not contain cylinder 1; P219A is the Bank 1 version. The sources describe the fault a little differently. OBD-Codes.com describes it as an air-fuel ratio imbalance for the whole bank, often from a large vacuum leak, exhaust leak, MAF or MAP sensor, or low fuel delivery. Honda's service bulletin names it 'air-fuel ratio variation of cylinder' on Bank 2 (the front bank), which points to one or more cylinders on that bank running differently from the others, such as a clogged injector. Mazda's CX-9 bulletin uses the name 'Bank 2 Air-Fuel Ratio Imbalance' and traces some cases to electrical noise in the A/F sensor wiring. OBD-Codes.com notes most vehicles need the fault on more than one drive cycle before the light comes on.

Severity: can I keep driving?

Stop and fix promptly

Get it fixed soon. OBD-Codes.com says P219B should be treated as severe and fixed as quickly as possible, because an engine bank running too rich or too lean hurts performance and fuel economy and often comes with misfire codes. If the engine misfires badly, shakes, loses power, or the check engine light flashes, keep driving to a minimum, because misfires can overheat and damage the catalytic converter.

Common symptoms

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

  1. A large engine vacuum leak (OBD-Codes.com)
  2. A faulty oxygen or A/F ratio sensor (OBD-Codes.com)
  3. Burnt, chafed, broken or disconnected wiring or connectors (OBD-Codes.com)
  4. Exhaust leaks (OBD-Codes.com)
  5. A faulty mass air flow (MAF) or manifold absolute pressure (MAP) sensor (OBD-Codes.com)
  6. A bad fuel pump or clogged fuel filter (OBD-Codes.com)
  7. Worn or clogged fuel injectors; on 2017-2019 Honda Pilot and Ridgeline and 2018-2019 Odyssey, Honda blames debris from the injector machining process or the high pressure pump (Honda Service Bulletin 21-010)
  8. Electrical noise in the A/F sensor signal wiring on 2011-2015 Mazda CX-9 (Mazda Service Bulletin 01-006/15)

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

  1. Read all stored codes and freeze frame data and write them down. OBD-Codes.com says to fix misfire, throttle position, MAP and MAF codes before diagnosing P219B.
  2. Check for technical service bulletins (TSBs) for your year, make, model and engine. Honda and Mazda both have bulletins for P219B on specific models.
  3. Inspect vacuum hoses, the intake and the exhaust for leaks, and look over oxygen sensor wiring and connectors for damage (OBD-Codes.com).
  4. With the engine warm and idling, watch the upstream oxygen sensors on a scan tool. OBD-Codes.com says a healthy pre-cat sensor keeps cycling between about 1 and 900 millivolts in closed loop; one that doesn't cycle may be bad if the engine is otherwise in good shape.
  5. Clear the code and drive to see if it returns. OBD-Codes.com warns an intermittent fault may need to get worse before it can be pinned down.

Typical fixes

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

  • The engine misfires, shakes, or the check engine light flashes
  • You own a Honda Pilot, Odyssey or Ridgeline or a Mazda CX-9 covered by a bulletin; a dealer can check whether the repair or warranty extension applies
  • Finding the cause needs injector testing, a smoke test or fuel pressure testing
  • The code keeps coming back after the obvious leaks and wiring are fixed

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

What is the difference between P219A and P219B?

Only the bank. P219A is Bank 1, the side of the engine with cylinder 1, and P219B is Bank 2, the other side of a V6 or V8. Honda calls Bank 2 the front bank on its V6 engines.

Is P219B serious?

OBD-Codes.com rates it severe and says to fix it as quickly as possible. It hurts fuel economy and performance, and it often comes with misfires that can damage the catalytic converter.

Is there a recall or warranty for P219B?

Not a recall, but Honda Service Bulletin 21-010 extends the warranty on fuel injector replacement for this code to 10 years or 150,000 miles on eligible 2017-2019 Pilot and Ridgeline and 2018-2019 Odyssey. Mazda has a wiring fix bulletin for the 2011-2015 CX-9. Ask a dealer to check your VIN.

Why do sources describe P219B differently?

OBD-Codes.com treats it as a whole-bank mixture problem, often from a vacuum leak or fuel delivery. Honda's bulletin calls it a cylinder-to-cylinder air-fuel variation and fixes it with new injectors, and Mazda traced some cases to wiring noise. The right fix depends on the vehicle, so check for a bulletin first.

How much does it cost to fix P219B?

None of these sources gives a repair cost. It can range from a vacuum hose to a set of injectors, so get a diagnosis or written estimate first, and check whether a warranty extension covers it.

Sources

  1. OBD-Codes.com: P219B Bank 2 Air/Fuel Ratio Imbalance (rated severe)
  2. Honda Service Bulletin 21-010: Warranty Extension, MIL with P0420/P0430, P030x and/or P219A/B (via NHTSA)
  3. Mazda Service Bulletin 01-006/15: MIL with DTCs P219A:00 and/or P219B:00, CX-9 (via NHTSA)

Last reviewed 2026-10-23. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.