P02AA code meaning
Cylinder 5 - Fuel Trim at Max Limit
Powertrain system Generic code P02xx codes Check engine light
What P02AA means
These codes belong to an individual-cylinder fuel correction: a diesel's cylinder balance control measures each cylinder's crankshaft acceleration and adjusts its injection quantity; on gasoline engines a cylinder-selective mixture control does the same. CARB requires the system to report when such a correction has used up its range or one cylinder causes an imbalance. P02AA means the correction for cylinder 5 is at its upper limit: the module keeps giving this cylinder more fuel and still cannot even it out – a sign that the cylinder receives too little fuel or builds too little pressure. GM and Ford use other codes for this (P0263 ff, P219A ff); no manufacturer document describing this code with thresholds was found, so the description follows CARB and published patents.
P02AA at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor1 to 4 hours
- Clears after repairAfter a drive cycle
Symptoms of P02AA
- Check engine light on
- Rough idle, vibration
- Lack of power, possibly misfire
Common causes of P02AA
- Most likelyInjector of cylinder 5 coked or partly clogged
- PossibleCompression loss in this cylinder (valve, rings, leak at injector or glow plug)
- PossibleInjector circuit high-resistance or connector
- PossibleGasoline: false air at this cylinder's intake (manifold gasket)
- Less likelyInjector correction code missing or wrong after replacement
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fuel injector cylinder 5Crankshaft position sensorEngine control module
What each part of P02AA means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 2 | Area: fuel and air metering (injector circuit). |
| AA | The exact fault in that area. |
What to do next
- Note P02AA and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P02AA
What does P02AA mean?
P02AA means "Cylinder 5 - Fuel Trim at Max Limit". These codes belong to an individual-cylinder fuel correction: a diesel's cylinder balance control measures each cylinder's crankshaft acceleration and adjusts its injection quantity; on gasoline engines a cylinder-selective mixture control does the same. It is a generic code, so it means the same on every make.
Is it safe to drive with P02AA?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P02AA fail an emissions test?
Yes, it can. P02AA is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P02AA to fix?
Difficulty: medium. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P02AA clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.