Cause
Failed accumulator
A hydraulic accumulator that no longer holds its charge. It stores pressurised fluid so the system can respond faster than its pump can build, which matters for a shift, an actuation, or the moment after a start-stop restart.
Its failure shows as a pump cycling far more often than it should, refilling a store that will not hold. Most are gas-charged behind a diaphragm, and the failure is the gas leaking away — after which the unit behaves as a plain length of pipe, with nothing leaking externally and every running pressure test passing. Watch pressure decay with the pump stopped: a healthy accumulator holds for a long time and a failed one drops at once, which distinguishes it from a leak that decays gradually.
Typically specialist work. Needs equipment or training most home workshops do not have.
Some of these codes mean you should stop driving
1 of the 1 codes this can cause indicate a fault where continuing to drive risks damage or is unsafe. Which one you have matters more than the cause does — read the code's own page before deciding.
Codes this can cause (1)
Codes where this is a likely explanation first, rather than merely a possible one.
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