P2289: Injector Control Pressure Too High Engine Off
What to do
The engine will usually start and run. This one points quite specifically at the pressure regulator or its return path, because with the engine stopped nothing is making pressure and the only question is why it has not been let go. If the over-pressure code for the running engine is stored alongside it, the two agree with each other and that is a reasonably firm diagnosis.
What this code means
Pressure is still standing in the injection control circuit after the engine has stopped. This is a genuinely specific observation and it narrows the diagnosis further than any of the running-engine codes can.
With the engine off, nothing is generating pressure — the pump is not turning. So any pressure that remains is pressure that has not been released, and there is only one thing whose job is releasing it. That makes this close to a direct accusation of the pressure regulator, or of the return path it opens into.
Why it matters beyond the code itself: an engine shut down with pressure still standing may fire on the next start before the module has commanded anything, or may crank against a system already loaded. It also means the seals in the high-pressure circuit are held under load while the engine sits, which is not what they were designed for.
The useful part for anyone reading a code list is that this code and the running-engine over-pressure code at P2288 stored together are strongly consistent with one another — both say the release path is not releasing — and that agreement is worth more than either alone.
Likely causes
Start here
- Faulty injection pressure regulator · moderate
- Regulator return path restricted · moderate
Less common
- Faulty injection control pressure sensor · moderate
- Damaged wiring to the pressure regulator · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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