P276A: Motor van transmissieoliepomp B — voedingsspanningscircuit onderbroken
Wat te doen
The car will drive normally — the most likely sign is that stop-start no longer switches the engine off. That is the system protecting itself rather than a battery problem, which is what usually gets blamed. You may also notice a slight delay before the car moves after the engine restarts. Worth diagnosing, not urgent.
Wat deze code betekent
The electric auxiliary transmission fluid pump B motor supply voltage circuit has an open circuit.
An automatic gearbox loses all its hydraulic pressure the moment the engine stops turning, and stop-start made that a problem worth solving.
The main pump is driven by the engine. Engine off, no pressure, no clutch applied — which is fine when the engine only stops at the end of a journey. On a car that shuts the engine off at every red light, the transmission would have to rebuild pressure before the car could move, and the delay is exactly the hesitation that makes people dislike stop-start.
So an electric auxiliary pump keeps pressure up while the engine is stopped, and lets the car pull away the instant the engine restarts. Hybrids need it for the same reason and more often. A fault here does not usually stop the car — it stops the stop-start, and many vehicles simply disable engine shutdown, which is the system failing safe.
The supply circuit is separate from the control signal, and this code names the supply. These pumps draw a substantial current, so the feed, its fuse, its ground and its relay matter as much as the motor — and a corroded ground reproduces the fault exactly.
What the driver notices is usually nothing, or that stop-start has stopped working. That is worth stating plainly, because an unexplained loss of stop-start is often blamed on the battery — and on a car with this code the transmission is the reason.
Pump B implies a pump A, so this is a vehicle with more than one auxiliary pump or one that numbers them for a second circuit. Read every stored code before assuming which unit is meant.
Transmission fluid is the first thing to check and the thing most often skipped.
It is not a lubricant that also happens to move things — it is the working fluid of a hydraulic machine. It carries the pressure that applies every clutch, it carries the heat away, it lubricates, and it is the friction surface itself: the additive package is tuned so clutches grip smoothly rather than snatching.
So fluid that is low, old, burnt or of the wrong specification changes how the transmission behaves, and it does so before any part has failed. Burnt fluid smells burnt and looks dark; healthy fluid is translucent. Checking it costs nothing and rules out a great deal.
"Filled for life" is a claim about the warranty, not the transmission. Many sealed units have no dipstick and a manufacturer schedule that never changes the fluid, and they still wear out faster on original fluid than on serviced fluid.
Waarschijnlijke oorzaken
Begin hier
- Gecorrodeerde of losse stekker · specialistisch
- Hulppomp transmissieolie defect · specialistisch
- Kabelboom beschadigd · specialistisch
- Slechte massaverbinding van de module · specialistisch
Minder vaak
- Transmissieolie te laag of versleten · gemiddeld
Symptomen
Betrokken onderdelen
Informatie, geen instructie
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Wat het de moeite waard maakt:
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- Wat het echt verholpen heeft — of dat niets dat deed, wat ook nuttig is om te weten.
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