Control Unit 6-speed SMG

Our refurbished pressure accumulators are equipped with a filling valve and freshly filled with new nitrogen gas.

The accumulator is responsible to store the pressure of the SMG system for later access by the actuators. The piston type accumulator has two cells: one cell storing the hydraulic fluid and one cell containing a gas to create counterpressure. Both cells are separated by a moving piston. A broken accumulator causes the pump to prime permanently.

Important: You will need to pay a core charge (deposit) of 300,00€ which will be refunded when you return your used part. You can learn more here. This is a repair service (no purchase of a product). Our terms and conditions and the right of withdrawal for the order of services apply.

The pump relay is responsible to turn on / off the hydraulic pump of the SMG system. A broken relay causes the pump to fail priming. Without hydraulic pressure, the system cannot engage the clutch or change gears.

Pictures shown are for illustration purpose only. Fits only E46 models.

The pump motor drives the gear pump, which generates the pressure for the SMG transmission. Both parts together form the hydraulic pump. Without hydraulic pressure, the transmission cannot perform any action – neither change gears, nor operate the clutch. Therefore, the hydraulic pump is the most important component in the system.

In most cases, it is sufficient to replace only the electric motor, as this is a wearing part. The gear pump fails only very rarely. Another advantage is that when only the pump motor is changed, the hydraulic system does not need to be bled afterwards, unless it has been opened.

We sell an original, brand new Magneti Marelli spare part – the same part you would get from BMW.