Clogged or partially blocked cylinder 3 injector from deposits or contaminated fuel; Injector internal fault such as a sticking pintle or weak spray pattern; Poor electrical connection, damaged wiring or corroded connector at the cylinder 3 injector; Low fuel pressure or restricted fuel supply affecting delivery (fuel filter, pump or regulator, depending on the engine); Vacuum or intake leak near cylinder 3 causing a local lean condition that mimics a restriction; Fault in the engine control unit injector driver circuit.

P02A4

Cylinder 3 - Injector Restricted.

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)
A4: FaultThe specific fault in that area

What it means

P02A4 means the engine control unit has detected that the fuel injector on cylinder 3 is restricted, so it is delivering less fuel than commanded. The fault is typically set when fuel trim, misfire or exhaust oxygen sensor data shows cylinder 3 running lean compared with the other cylinders. The exact monitoring method varies by engine and manufacturer.

Symptoms

Rough idle or a noticeable shake at idle
Misfire or hesitation under load, especially on cylinder 3
Reduced power and poor acceleration
Poor fuel economy
Engine management light on
Hard starting or uneven running when cold

Possible causes

Clogged or partially blocked cylinder 3 injector from deposits or contaminated fuellikely
Injector internal fault such as a sticking pintle or weak spray patternlikely
Poor electrical connection, damaged wiring or corroded connector at the cylinder 3 injectorpossible
Low fuel pressure or restricted fuel supply affecting delivery (fuel filter, pump or regulator, depending on the engine)possible
Vacuum or intake leak near cylinder 3 causing a local lean condition that mimics a restrictionpossible
Fault in the engine control unit injector driver circuitrare

How to diagnose

Read all stored and pending codes and record the freeze frame data, noting engine load, temperature and fuel trim values at the time of setting.
Check for other related codes such as misfires, lean codes or fuel pressure faults, and deal with those first if present.
Inspect the cylinder 3 injector connector and wiring for damage, corrosion, heat damage or loose pins.
Look for intake leaks near cylinder 3, such as cracked hoses, split intake seals or loose manifold connections.
Check fuel pressure against the manufacturer's specification, and inspect the fuel filter where one is fitted and serviceable.
Use live data to compare fuel trims and misfire counts for cylinder 3 against the other cylinders, and check whether the fault is worse at idle or under load.
Swap the cylinder 3 injector with another cylinder, if the engine design allows, and see whether the fault follows the injector.
Test the injector resistance and spray pattern or flow rate using the manufacturer's procedure, as the method depends on the engine and injection type.

How to fix

Clean the injector only if the manufacturer's procedure allows it, otherwise replace the restricted injector.
Replace a faulty cylinder 3 injector, following the correct fitting procedure and any coding or adaptation steps for that engine.
Repair or replace damaged wiring or the connector at the injector.
Replace a blocked fuel filter or repair the fuel supply fault that is causing low pressure.
Repair any intake leaks found near cylinder 3.
Drain and replace badly contaminated fuel if it is found to be the source of the blockage.

Can I keep driving?

Medium severity

The car can usually be driven short distances to get it checked, but a restricted injector can cause a lean misfire that may damage the catalytic converter or the engine if left. Avoid heavy loads and fix it soon.

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