P03E2

What it means

P03E2 is a generic code meaning the engine control unit has seen the combustion pressure variation in cylinder 8 fall below its expected range. The cylinder 8 pressure signal, or the combustion quality figure derived from it, was too weak or too uniform compared with the other cylinders. How the pressure is measured depends on the engine, so the exact setting criteria vary by manufacturer and model.

Symptoms

• Engine warning light on
• Rough running or a misfire-like shake, especially at idle
• Loss of power or flat response under load
• Poor fuel economy
• Possible additional misfire or fuel trim codes stored

Possible causes

• Weak or failed combustion on cylinder 8 from a worn or faulty spark plug, ignition coil or injectorlikely
• Faulty cylinder pressure sensor or its wiring and connector, on engines that have onelikely
• Low mechanical compression in cylinder 8 from valve, piston ring or head gasket problemspossible
• Intake or exhaust restriction, or an air leak affecting cylinder 8 (for example a leaking intake manifold gasket or a carbon-blocked intake valve)possible
• Fuel delivery problem to cylinder 8, such as a clogged or leaking injector or low fuel pressurepossible
• Valve timing fault or variable valve actuation problem affecting cylinder 8rare
• Control unit fault or outdated calibration where the manufacturer lists one as a known causerare

How to diagnose

1. Read all stored codes and freeze frame data, noting engine load, speed and temperature when the code set, and look for misfire, fuel trim or sensor circuit codes
2. Check live misfire counters and cylinder balance data to see whether cylinder 8 is weak compared with the others
3. Inspect the wiring and connectors to the cylinder 8 coil, injector and any pressure sensor for damage, corrosion, chafing or oil contamination
4. Remove and inspect the cylinder 8 spark plug, and swap the coil with another cylinder to see if the fault follows it
5. Check for intake leaks and restrictions, and fuel pressure against the manufacturer's specification
6. Test the cylinder 8 injector for correct resistance and operation
7. Carry out a compression or leak-down test on cylinder 8 if the ignition and fuel checks are good
8. Check valve timing and variable valve operation against model-specific data, and see whether the manufacturer has a calibration update for this code

How to fix

• Replace the worn spark plug or faulty ignition coil on cylinder 8
• Repair or replace damaged wiring, connectors or the cylinder pressure sensor, following model-specific procedures
• Clean or replace the faulty cylinder 8 injector, and correct any fuel pressure fault
• Repair intake leaks or clear intake restrictions, including carbon build-up where that is the cause
• Carry out the necessary engine repair for low compression, such as valve, ring or head gasket work
• Apply a manufacturer calibration update only where an outdated one is a documented cause

Can I keep driving?

Nearby codes

• P03E1GenericCylinder 8 Pressure Too High
• P03E3GenericCylinder 8 Pressure Variation High