Injector Control Pressure Erratic

Possible causes

• CommonLow engine oil level, or oil of the wrong grade
• CommonFailed injector control pressure sensor
• CommonCorroded or oil-contaminated connector
• CommonLeaking high-pressure oil rail, fitting or standpipe
• PossibleFailed high-pressure oil pump
• PossibleFailed pressure regulator valve

What you might notice

• Hard starting or no start
• Rough running and misfire
• Loss of power
• White smoke on start-up
• Check engine light on

What to check, in order

1. Check the oil level and condition. Aerated oil produces exactly this and is often caused by an overfilled sump as well as an underfilled one.
2. Look for leaks that could draw air into the high-pressure circuit.
3. Watch the pressure trace on the live data screen while the fault is present.
4. Check the engine oil level, condition and grade first. These systems use engine oil at very high pressure to fire the injectors, so oil that is low, degraded or the wrong grade causes faults here before anything else does.
5. Inspect the connector for oil contamination - a leaking sensor seal fills its own plug.
6. Watch the reported pressure on the live data screen during cranking and at idle.
7. Look for external oil leaks around the high-pressure rail and its fittings.
8. Read all codes. A pressure-too-low code alongside a sensor code usually means the pressure is genuinely low and the sensor is right.