What it means
During engine cranking, injector control pressure is below the expected limit. This may prevent the engine from starting; the code does not identify the cause by itself.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
On systems that use high-pressure engine oil to actuate the injectors, the control module monitors injector control pressure while the starter is turning the engine. P2291 sets when pressure fails to reach the required level during cranking, which can leave the injectors unable to deliver fuel properly.
Common causes
Most likely first.
- High-pressure oil system leak
- High-pressure oil pump unable to build pressure
- Injector pressure regulator stuck open or faulty
- Low engine oil level or incorrect oil viscosity
Symptoms
- Check-engine light on
- Extended cranking or no start
- Rough running immediately after starting
How to diagnose it
- Use a scan tool to review freeze-frame data and compare commanded with measured injector control pressure during cranking.
- Check the engine oil level and confirm the oil grade matches the manufacturer's specification, since low or unsuitable oil can impair pressure buildup.
- Inspect the high-pressure oil pump, rails, lines, and related connections for visible oil leaks.
- Check the injector pressure regulator and its wiring or connector for damage or sticking, following the vehicle's service information.
- If the external checks pass, test high-pressure oil system leakage and pump output using the manufacturer's procedure.
Common fixes
- Correct the engine oil level or use oil of the specified grade.
- Repair a leaking high-pressure oil line, connection, or seal.
- Repair or replace a faulty injector pressure regulator.
- Repair or replace a high-pressure oil pump that fails its output test.
Can I keep driving?
If the engine will not start or cranks for a long time, avoid repeated extended cranking because it can overheat the starter and drain the battery. If it starts but runs roughly, limit driving and arrange diagnosis promptly; low injector control pressure can cause stalling.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.