U0287: Lost Communication With Transmission Fluid Pump Module A
What to do
If your stop-start has stopped working and this code is present, they are the same problem — and the car switching stop-start off is it protecting the gearbox, which is the right thing for it to do.
This pump keeps the transmission pressurised while the engine is off, so that drive is there the instant it restarts. Without it, pressure bleeds away.
The thing to watch for, and to act on: a clunk or a delay when the engine restarts and you pull away. Repeated harsh engagement is hard on the transmission's clutches, so if the car is banging into gear, stop using stop-start if you can switch it off manually, and get it looked at rather than living with it.
If your car is a hybrid, treat this as more urgent. The transmission may be losing pressure during electric-only running, which is most of the time in town — and that is a bigger risk than an occasional harsh restart.
What this code means
The first transmission fluid pump module has stopped being heard from. See U0200 for the block's framing.
An automatic gearbox has always had a pump driven by the engine, and the reason a second, electrically driven one exists is stop-start.
A conventional transmission pump turns with the engine. Stop the engine at a junction and the pump stops, line pressure bleeds away, and the clutches that were holding a gear release. Restarting then means re-pressurising the whole system before the vehicle can move — which is the delay and the shunt that early stop-start systems were criticised for.
An auxiliary electric pump solves it by keeping the transmission pressurised while the engine is off, so drive is available the instant it restarts. On hybrids the same pump does more: it maintains pressure through every period of electric-only running, which on some vehicles is most of the time.
The consequences of losing it follow directly, and they are why this is not filed as a low-severity body code:
- Stop-start will usually disable itself, which is the vehicle protecting the transmission and is the correct response.
- If it does not, the engagement after a restart can be delayed or harsh, and repeated harsh engagement is genuinely hard on clutches.
- On a hybrid, the transmission may lose pressure during electric running, which is the more serious version and the reason to act promptly.
So the practical advice is specific: if stop-start has switched itself off and this code is stored, do not treat that as two problems. And if the vehicle is banging into gear after a restart, that is a reason to stop using it rather than to live with it.
The pump is usually mounted on or near the transmission, so heat, vibration and its connector dominate the causes.
Likely causes
Start here
- Corroded or loose connector · easy
- Heat damage to sensor or wiring · moderate
- Damaged wiring harness · moderate
- Failed power or earth supply to the module · moderate
Less common
- Damaged data bus wiring · 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.
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