P03D2

What it means

P03D2 is a generic code meaning the engine control unit has found the signal from the cylinder 7 pressure sensor to be outside the expected range or not behaving plausibly. The sensor measures pressure inside the combustion chamber, so the control unit compares its output with expected values for the current engine speed and load, and with other cylinders. Not every engine has these sensors, and where they are fitted the exact strategy depends on the manufacturer and engine.

Symptoms

• Engine warning light on
• Rough running or uneven idle
• Misfire on cylinder 7 or reduced smoothness under load
• Loss of power or reduced performance
• Poor fuel economy
• Engine running in a limited power mode

Possible causes

• Damaged wiring, poor connection or corroded terminals in the cylinder 7 pressure sensor circuitlikely
• Faulty or drifting cylinder 7 pressure sensorlikely
• Carbon fouling or contamination of the sensor tip or its portpossible
• Genuine combustion problem in cylinder 7, such as a misfire, low compression or a faulty injector or ignition componentpossible
• Sensor supply or reference voltage fault, or poor earthpossible
• Fault in the engine control unit or its sensor input stagerare

How to diagnose

1. Read all stored and pending codes and note the freeze frame data, including engine speed, load and temperature, and look for related misfire or other cylinder pressure sensor codes.
2. Check for technical service bulletins and confirm that this engine is fitted with cylinder pressure sensors, as the layout depends on the model and engine.
3. Inspect the sensor wiring, connector and terminals for damage, chafing, heat damage, moisture or corrosion, and check the connector locks fully.
4. View live data for the cylinder 7 pressure signal and compare it with the other cylinders at idle and under load, checking for a flat, noisy or implausible reading.
5. Check the sensor supply voltage, signal and earth at the connector against the manufacturer's specification, and test the wiring for continuity and shorts.
6. Check for misfires and review cylinder 7 ignition and injector condition to rule out a real combustion fault.
7. If the electrical checks pass, carry out a compression or leak-down test on cylinder 7.
8. Remove and inspect the sensor for fouling or damage, following the manufacturer's procedure.

How to fix

• Repair or replace damaged wiring and clean or replace corroded connector terminals.
• Replace the cylinder 7 pressure sensor if it is faulty, then clear the code and verify the repair with a road test.
• Clean or replace a sensor affected by fouling, if the manufacturer permits.
• Repair the underlying cylinder 7 combustion fault, such as a faulty injector, ignition component or mechanical problem.
• Repair the supply or earth fault, and update the control unit software only if the manufacturer lists an outdated calibration as a known cause.

Can I keep driving?

Nearby codes

• P03D1GenericCylinder 7 Pressure Sensor Circuit
• P03D3GenericCylinder 7 Pressure Sensor Circuit Low