Worn, fouled or incorrectly gapped spark plug on cylinder 7 (petrol engines); Faulty ignition coil or coil wiring/connector for cylinder 7; Faulty, leaking or clogged fuel injector on cylinder 7, or wiring fault to it; Low compression in cylinder 7 from valve, piston ring or head gasket wear or damage; Vacuum or intake leak affecting cylinder 7, such as a cracked manifold runner or leaking seal; Poor fuel quality or fuel delivery problem affecting mixture; Crankshaft position sensor or reluctor wheel fault causing false cylinder readings.

P03DA

Cylinder 7 Combustion Performance.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
3: AreaIgnition system or misfire
DA: FaultThe specific fault in that area

What it means

P03DA is a generic powertrain code meaning the engine control unit has judged that combustion in cylinder 7 is not performing as expected. It usually sets when the ECU detects a deviation in that cylinder, such as a torque contribution or crankshaft speed change that differs from the other cylinders. The exact monitoring method and thresholds depend on the manufacturer and engine, and the code only applies to engines with at least seven cylinders.

Symptoms

Engine management light on, possibly flashing if misfire is severe
Rough idle or vibration, especially when cold or under load
Hesitation, flat spots or loss of power
Raised fuel consumption
Possible misfire codes stored alongside it
Uneven or lumpy running with a smell of unburnt fuel

Possible causes

Worn, fouled or incorrectly gapped spark plug on cylinder 7 (petrol engines)likely
Faulty ignition coil or coil wiring/connector for cylinder 7likely
Faulty, leaking or clogged fuel injector on cylinder 7, or wiring fault to itlikely
Low compression in cylinder 7 from valve, piston ring or head gasket wear or damagepossible
Vacuum or intake leak affecting cylinder 7, such as a cracked manifold runner or leaking sealpossible
Poor fuel quality or fuel delivery problem affecting mixturepossible
Crankshaft position sensor or reluctor wheel fault causing false cylinder readingsrare

How to diagnose

Read all stored codes and freeze frame data to note engine load, speed, temperature and any accompanying misfire or fuel trim codes
Inspect the wiring and connectors for the cylinder 7 coil and injector for damage, corrosion or looseness
Check live data for misfire counts and confirm the fault follows cylinder 7 rather than moving around
Remove and inspect the cylinder 7 spark plug for wear, fouling, oil or fuel contamination, and check the gap (petrol engines)
Swap the cylinder 7 coil with another cylinder, clear the codes, and see whether the fault moves
Test the cylinder 7 injector electrically and check its spray pattern and balance, following the manufacturer procedure
Perform a compression or cylinder leak-down test on cylinder 7
Smoke test the intake for leaks and check fuel pressure and quality if the cause is still not found

How to fix

Replace the cylinder 7 spark plug, or the full set if they are due for service
Replace the faulty ignition coil on cylinder 7
Repair damaged wiring or connectors, or replace or professionally clean/test the faulty injector
Repair mechanical faults found in cylinder 7, such as valve or ring damage or a head gasket leak
Repair intake leaks by replacing the leaking seal, hose or manifold part
Replace a faulty crankshaft sensor if testing shows it is causing the fault, and drain and replace poor-quality fuel

Can I keep driving?

Medium severity

Gentle short-term driving is usually possible, but avoid heavy loads and high revs, and get it checked soon. If the engine management light flashes or the engine runs very roughly, stop driving, as unburnt fuel can damage the catalytic converter.

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