Faulty, clogged or leaking fuel injector on cylinder 7; Air leak at the cylinder 7 intake runner, manifold gasket or a nearby vacuum hose (lean condition); Ignition fault on cylinder 7 such as a worn spark plug or failing coil causing misfire and unburnt oxygen; Wiring or connector fault on the cylinder 7 injector circuit; Exhaust leak upstream of the oxygen or air-fuel sensor skewing readings; Mechanical problem on cylinder 7 such as low compression, a burnt valve or a leaking head gasket; Faulty air-fuel or oxygen sensor on the bank containing cylinder 7.

P02B2

Cylinder 7 - Fuel Trim at Max Limit.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
2: AreaFuel and air metering (injector circuit)
B2: FaultThe specific fault in that area

What it means

P02B2 means the engine control unit has found that the fuel trim correction for cylinder 7 has reached its maximum limit. The ECU is adding or removing as much fuel as it is allowed to for that cylinder and still cannot bring the mixture to target. It only applies to engines with at least seven cylinders, and how the correction is calculated depends on the engine.

Symptoms

Engine management light on
Rough idle or a noticeable misfire
Hesitation or flat spots under acceleration
Poor fuel economy
Fuel smell or raised exhaust smell
Possible additional misfire or fuel trim codes stored

Possible causes

Faulty, clogged or leaking fuel injector on cylinder 7likely
Air leak at the cylinder 7 intake runner, manifold gasket or a nearby vacuum hose (lean condition)likely
Ignition fault on cylinder 7 such as a worn spark plug or failing coil causing misfire and unburnt oxygenpossible
Wiring or connector fault on the cylinder 7 injector circuitpossible
Exhaust leak upstream of the oxygen or air-fuel sensor skewing readingspossible
Mechanical problem on cylinder 7 such as low compression, a burnt valve or a leaking head gasketrare
Faulty air-fuel or oxygen sensor on the bank containing cylinder 7rare

How to diagnose

Read all stored and pending codes and record the freeze frame data, noting load, engine temperature and fuel trim values when the fault set.
Check for related codes such as misfires, injector circuit faults or bank fuel trim codes, and deal with those first.
Where the scan tool supports it, view live fuel trim and misfire counts for each cylinder at idle and under load to see whether the correction is lean or rich.
Inspect the cylinder 7 injector connector, wiring and earth points for damage, corrosion or looseness, and check for vacuum hoses and intake seals near that cylinder.
Smoke test the intake system to find air leaks, paying attention to the cylinder 7 runner and manifold gasket.
Inspect the exhaust for leaks upstream of the sensors on the relevant bank.
Swap the cylinder 7 coil, spark plug or injector with a neighbouring cylinder and see whether the fault moves with the part.
Test injector resistance and spray pattern or flow, check fuel pressure against the manufacturer's specification, and carry out compression or leak-down tests if the fault stays on cylinder 7.

How to fix

Replace or professionally clean and flow-test the faulty cylinder 7 injector.
Repair the intake air leak by replacing the manifold gasket, seals or damaged hoses.
Replace the worn spark plug or failing ignition coil on cylinder 7.
Repair or replace damaged injector wiring, terminals or connectors.
Repair the exhaust leak ahead of the sensor, or replace the sensor if testing shows it is faulty.
Carry out the necessary engine repair if compression or valve problems are confirmed.

Can I keep driving?

Medium severity

The car can usually be driven for a short time to get it to a garage, but a lasting lean or rich condition or misfire can overheat the catalytic converter or damage the engine. Avoid heavy loads and book diagnosis soon, and stop if it runs very roughly or the warning light flashes.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.