P219A: Bank 1 Air-Fuel Ratio Imbalance
Quick Answer
Safe to drive (short-term)
P219A means the engine computer has found that the cylinders on bank 1 (the side with cylinder 1, or the whole engine on a four-cylinder) are not all running at the same air-fuel ratio. Depending on the manufacturer, it spots this from ripples in the upstream air-fuel ratio sensor signal, from small changes in crankshaft speed, or both. The usual causes are a leaking or clogged injector, an intake leak at one runner, an ignition or compression problem on one cylinder, or a faulty upstream sensor.
- Severity
- Moderate · Fuel System
- Estimated repair cost
- From €40 to €400+, varies by vehicle
€40 or €400, depending on your car.
- Replace one ignition coil€40–€180
- Replace one petrol fuel injector€100–€400
A scan shows whether P219A is really stored on your car, which codes sit next to it and how urgent each one is.
A scan needs a Bluetooth OBD2 adapter (Bluetooth LE on iPhone), about €25-60; the built-in demo runs without one. See which adapter to buy
What does P219A mean?
P219A is a fuel system-related diagnostic trouble code classified as moderate severity.
What are the symptoms of P219A?
- Check engine light on, often with no obvious change in how the car drives
- Slightly rough or uneven idle
- Hesitation or a faint stumble under light load
- Worse fuel economy
- Fuel smell from the exhaust when one cylinder runs rich
- Misfire codes stored alongside P219A
What causes P219A?
Leaking, clogged or sticking fuel injector on one cylinder
: high
Intake air leak at one intake runner or gasket, or deposits on one cylinder's intake port or valve
: medium
Ignition fault on one cylinder, such as a worn spark plug or a failing coil
: medium
Low compression on one cylinder from a valve or piston ring problem
: low
Faulty upstream air-fuel ratio sensor or its wiring
: medium
Exhaust leak ahead of the upstream sensor
: low
Is it safe to drive with P219A?
Generally yes, for short-term driving. Usually safe to drive gently to a workshop, but do not leave it for months. One cylinder running richer or leaner than the others raises emissions and fuel use, and if it develops into a misfire the unburned fuel can overheat the catalytic converter. If the check engine light starts flashing, the engine shakes or you smell raw fuel, stop driving and get it checked.
How do you diagnose P219A?
- Read every stored code and the freeze frame. Some manufacturers store a second code that names the weak cylinder, and any misfire, fuel trim or air-fuel ratio sensor code stored with P219A narrows the search
- Check the long-term fuel trims on a warm engine with a generic OBD2 reader. They show whether the bank as a whole is being corrected rich or lean, but not which cylinder is out of line
- On many newer cars the Mode 06 test results include a misfire count for each cylinder. A cylinder with a count well above the others is the first suspect, even if no misfire code is stored
- Check for intake leaks with a smoke test, paying attention to the gaskets and runners of individual cylinders, and look for exhaust leaks ahead of the upstream sensor
- Inspect the spark plugs and check the ignition coils, swapping a suspect coil to another cylinder to see whether the fault follows it
- Test the injectors. A workshop can use the manufacturer's tester to trim fuel to each cylinder in turn and watch the response, or flow and leak-test the injectors off the car; a generic reader cannot run these tests
- If the injectors and ignition check out, run a compression test and inspect the intake valves for deposits, then check the upstream air-fuel ratio sensor and its wiring
How much does P219A cost to fix?
| Repair | Parts Cost | Labor Cost | Total Estimate | DIY Difficulty |
|---|---|---|---|---|
| Professional fuel injector cleaning (petrol) | €20–€60 | €60–€200 | €80–€260 | Professional |
| Replace one petrol fuel injector | €50–€250 | €50–€150 | €100–€400 | Moderate |
| Fix intake vacuum leak (hose, clamp or PCV fault) | €10–€60 | €40–€150 | €50–€210 | Moderate |
| Replace one ignition coil | €20–€120 | €20–€60 | €40–€180 | Easy |
| Replace upstream wideband (air-fuel ratio) sensor, OE quality | €100–€280 | €50–€120 | €150–€400 | Moderate |
| Repair exhaust leak at the manifold gasket or studs ahead of the sensor | €20–€100 | €60–€200 | €80–€300 | Moderate |
Prices estimated as of October 2026. Costs vary by region, vehicle, and shop.
P219A on specific vehicles
P219A on Toyota
Toyota Tundra 4.6 V8 · Toyota Venza 2.7
Related diagnostic codes
Common questions about P219A
- What does P219A mean?
- P219A means the engine computer has detected that the cylinders on bank 1 are not all running at the same air-fuel ratio. Instead of the whole bank being too rich or too lean, one cylinder is out of step with the others. Bank 1 is the side of the engine with cylinder 1; on a four-cylinder engine it is the whole engine.
- What is the most common cause of P219A?
- A fuel injector that leaks, sprays unevenly or is partly blocked is the usual suspect, because it changes the mixture of one cylinder only. An intake leak at one runner, a weak spark plug or coil, deposits on one intake valve, low compression on one cylinder or a faulty upstream air-fuel ratio sensor can produce the same code, so test before replacing parts.
- Can a bad oxygen sensor cause P219A?
- Yes. The engine computer uses the upstream air-fuel ratio sensor to spot the imbalance, so a sensor that is contaminated, slow or poorly connected can trigger the code on a healthy engine. It is not the most likely cause, though. Check the injectors, the ignition and for intake leaks first, especially if a misfire code or a cylinder-specific code is stored as well.
- Why do I only see P219A on some cars?
- Californian OBD II rules phased in air-fuel ratio cylinder imbalance monitoring from the 2011 model year (a quarter of each manufacturer's cars) to all cars from 2014, so the code is typical of cars built for North America from then on. Cars built only to European rules are not bound by that requirement, so whether they run this monitor is up to the manufacturer; a car without it tends to report a similar fault as a misfire or fuel trim code instead.
- Is it safe to drive with P219A?
- For a short time, usually yes, if the engine runs smoothly and the light is steady. It is not a code to ignore: an injector that leaks can wash oil from the cylinder wall and send raw fuel to the catalytic converter, and an imbalance often turns into a misfire. If the light flashes or the engine shakes, stop driving and get it checked.
- How much does it cost to fix P219A?
- It depends on the cause. Professional injector cleaning costs about €80 to €260, and a single replacement petrol injector about €100 to €400 fitted. An intake leak repair is typically €50 to €210, one ignition coil €40 to €180, an exhaust leak ahead of the sensor €80 to €300, and an upstream air-fuel ratio sensor €150 to €400.
Read our detailed guides
Sources
- ttundra.com ttundra.com/835/bank_1_air_fuel_ratio_imbalance_p219a_p219f_p21a0_p21a3_.html
- en.wikipedia.org en.wikipedia.org/wiki/Toyota_UR_engine
- tovenza.com tovenza.com/bank_1_air_fuel_ratio_imbalance_p219a_p219c_p219f_-1052.html
- en.wikipedia.org en.wikipedia.org/wiki/Toyota_AR_engine