P219A The engine computer has detected that the cylinders on bank 1 are running at noticeably different air-fuel ratios from each other

Bank 1 air-fuel ratio imbalance

P219A in short

P219A means the cylinders on bank 1 aren't all getting the same air-fuel mixture. Common causes are a leaking or clogged fuel injector, an intake or exhaust leak, a faulty oxygen or airflow sensor, and low fuel pressure. Have it inspected soon; if the check engine light starts flashing, stop and let the engine cool.

Each cylinder should burn roughly the same air-fuel mixture. Emissions rules require the engine computer to watch for an imbalance between cylinders, because one rich or lean cylinder raises emissions even when the average looks fine.

The computer usually spots it from ripples in the oxygen sensor signal or tiny changes in crankshaft speed as each cylinder fires. P219A sets for bank 1, the side with cylinder 1; on a four-cylinder engine that's the whole engine.

Imbalance often travels with misfire and catalyst codes. Honda's V6 bulletins list it alongside P0300-P0306 and P0430, and Acura collected parts from cars with the same mix. Toyota and Subaru issued fixes for some Corollas and BRZs, Subaru's being a software update to stop false detection.

Most likely causes

  1. Leaking, clogged or mismatched fuel injector

    Common general cause
    Why it ranks here
    One injector delivering more or less fuel than the rest is the classic cause; GM's bulletin directs an injector balance test and a rich/lean injector check.
    What would change this
    Likelier if an injector balance test or misfire count singles out one cylinder.
    How to test the fuel injector

  2. Intake or vacuum leak near one cylinder

    Common general cause
    Why it ranks here
    A leak close to one intake port leans that cylinder alone. KBB lists vacuum leaks first.
    What would change this
    Likelier if lean codes such as P0171 are also stored.
    How to test the vacuum hoses and intake leaks

  3. Faulty upstream oxygen sensor or exhaust leak

    Possible — needs testing
    Why it ranks here
    The computer often detects imbalance through the oxygen sensor, so a slow sensor or an exhaust leak can upset the reading.
    What would change this
    Likelier if the sensor responds slowly in live data.
    How to test the oxygen (o2) sensor

  4. MAF or MAP sensor fault, or low fuel pressure

    Possible — needs testing
    Why it ranks here
    KBB lists MAF/MAP faults and low fuel pressure, which can magnify differences between cylinders.
    What would change this
    Likelier if fuel trims are off on both banks or pressure tests low.
    How to test the mass airflow (maf) sensor

  5. Engine computer software (false detection)

    Supported by vehicle data
    Why it ranks here
    Subaru reprogrammed the 2017-2019 BRZ to prevent incorrect P219A detection; Toyota has a repair procedure for some 2012-2014 Corollas.
    What would change this
    Likelier on those models when the engine runs well.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Read all codes and freeze-frame data, noting misfire, lean or rich, and catalyst codes stored with P219A

    Low riskTool: OBD-II scan tool

  2. Run an injector balance test and check fuel pressure and oxygen sensor response

    Best left to a shopTool: Bidirectional scan tool, fuel pressure gauge

    Warning:The fuel system is under pressure; relieve it as the maker specifies and keep sparks and flames away.

Symptoms

  • Check engine light, steady
  • Rough idle or shaking
  • Worse fuel economy
  • Check engine light flashing, or the engine shakes and stumbles under load Gets more serious: stop and have it checked.

Compare with: Rough idle with the check engine light on, Car shaking with the check engine light on

How to fix

  1. Ask a dealer whether a bulletin or software update covers your VIN; Honda, Toyota, Subaru and GM have published P219A information.

Parts and cost context

  • Fuel injector:Replace an injector only after a balance test or equivalent singles it out. Labour varies; get a quote.
  • Oxygen (O2) sensor:Test the upstream oxygen sensor's response before replacing it. Labour varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Toyota

  • 2012–2014 · Corolla

    Supported by vehicle data

    P219A on the 2ZR-FE; Toyota publishes a repair procedure. Whether the bulletin is still current is not verified.

  • T-SB-0107-14Status unverified

    MIL with P219A (Bank 1 Air-Fuel Ratio Imbalance) on Corolla and Matrix 2ZR-FE

    2012–2014corolla, matrix · issued · NHTSA 10109554

    MIL with P219A on 2ZR-FE engines; follow the bulletin's repair procedure.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Honda

  • 2018–2019 · Odyssey

    Supported by vehicle data

    P219A alongside misfire or catalyst codes on the V6. Whether the bulletins are still current is not verified.

  • 2016–2019 · Pilot

    Supported by vehicle data

    P219A with misfire or catalyst codes on the V6. Whether the bulletins are still current is not verified.

  • 2017–2019 · Ridgeline

    Supported by vehicle data

    Same V6 bulletins as the Odyssey and Pilot. Whether the bulletins are still current is not verified.

  • A18-025Status unverified

    MIL with P0300-P0306 or P219A/B (Odyssey, Pilot, Ridgeline)

    2017–2019odyssey, pilot, ridgeline · issued · NHTSA 10187003

    MIL with P0300-P0306 or P219A/B on 3.5L V6 models.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • A17-036Status unverified

    MIL with P0430, possibly with P030X and P219A/P219B

    2016–2018odyssey, pilot, ridgeline · issued · NHTSA 10162448

    MIL with P0430, possibly with P030X misfire and P219A/P219B air-fuel ratio variation codes.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Subaru

  • 2017–2019 · BRZ

    Supported by vehicle data

    Software update to stop false P219A detection. Whether the bulletin is still current is not verified.

  • 11-184-18Status unverified

    ECM reprogram to prevent incorrect P119F/P219A detection (BRZ)

    2017–2019brz · issued · NHTSA 10153613

    ECM reprogram to prevent incorrect detection of P119F and P219A.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Acura

  • 2016–2020 · MDX

    Supported by vehicle data

    Acura asked dealers to collect parts from cars with P219A/B, misfire or lean codes; no fix published in the record. Not a repair bulletin.

Chevrolet

  • 2010–2015 · Equinox

    Supported by vehicle data

    GM diagnostic guidance for P219A focusing on injector balance. Whether the bulletin is still current is not verified.

  • PIP5301Status unverified

    P219A: if injector balance test does not isolate the cause, test injectors for rich or lean

    2010–2015equinox, captiva · issued · NHTSA 10115033

    P219A: use service information; if the injector balance test doesn't isolate it, evaluate injectors for rich or lean. Also Buick Verano and GMC Terrain.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • PIP5929Status unverified

    Diagnostic tips for MIL with P219A (Encore GX, Trailblazer, Trax)

    2021–2024trailblazer, trax · issued · NHTSA 10239163

    Diagnostic tips for MIL with P219A. Also Buick Encore GX.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • P0300Random or multiple-cylinder misfire detected

    Shares causes Supported by vehicle data

    Honda's V6 bulletin covers P0300-P0306 misfires and P219A together.

  • P0430Catalytic converter efficiency below the computer's limit (Bank 2)

    Shares causes Supported by vehicle data

    Honda lists P219A as a possible companion to the bank 2 catalyst efficiency code P0430.

  • P0171Engine computer has reached its limit adding fuel on bank 1: the mixture is lean

    Shares causes Possible — needs testing

    Acura's parts request covers lean codes P0171/P0174 alongside P219A; an air leak can set both.

All Fuel trim (air-fuel mixture) codes

P219A questions

Can I drive with P219A?

Usually for a short time if the engine runs smoothly and the light is steady. If the light flashes or the engine shakes, stop: that means misfire that can damage the catalytic converter.

Will a fuel system cleaner fix P219A?

It might help a slightly dirty injector, but it won't fix a leak, a failed sensor or a stuck injector. A balance test tells you which cylinder is off.

Sources and review

  1. p219a Code - Bank 1 Air-Fuel Ratio Imbalance — Kelley Blue Book (KBB Service Advisor)
  2. A17-036: MIL with P0430, possibly with P030X and P219A/P219B — American Honda Motor Co. / NHTSA ,
  3. 2023 Integra Owner's Manual: Indicator, Coming On/Blinking — American Honda Motor Co.
  4. Final Regulation Order: 13 CCR §1968.2, Malfunction and Diagnostic System Requirements (OBD II), 2004 and subsequent model-year passenger cars, light-duty trucks and medium-duty vehicles (2015 amendments) — California Air Resources Board
  5. 2026 Honda Pilot Owner's Manual: Indicator Coming On/Blinking (Malfunction Indicator Lamp) — American Honda Motor Co.
  6. PIP5301: P219A: if injector balance test does not isolate the cause, test injectors for rich or lean — General Motors / NHTSA ,
  7. 11-184-18: ECM reprogram to prevent incorrect P119F/P219A detection (BRZ) — Subaru of America / NHTSA ,
  8. T-SB-0107-14: MIL with P219A (Bank 1 Air-Fuel Ratio Imbalance) on Corolla and Matrix 2ZR-FE — Toyota Motor Sales USA / NHTSA ,
  9. A18-025: MIL with P0300-P0306 or P219A/B (Odyssey, Pilot, Ridgeline) — American Honda Motor Co. / NHTSA ,
  10. Dealer message (2021-08-30): Parts request: MIL with P030X, P0171/P0174 or P219A/B (MDX, RDX, TLX) — American Honda Motor Co. / NHTSA ,
  11. PIP5929: Diagnostic tips for MIL with P219A (Encore GX, Trailblazer, Trax) — General Motors / NHTSA ,
Last reviewed
Written by
Saurabh K.
Editorial review
Pending
Technician review
Technician review pending

This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error

My Car

Pick your car and code pages will point out notes and bulletins for it. Saved only in this browser.

Fill this in from your VIN

Used once to identify your engine; not stored.