12 14 550 Replacing control unit (DME) (N54)

WARNING: This page is about a different car, the 2016 BMW Z4, 2015 BMW Z4, and 2014 BMW Z4. However, it is still accessible from the selected car via links, so may be relevant.

IMPORTANT: Read and comply with notes on PROTECTION AGAINST ELECTROSTATIC DISCHARGE (ESD PROTECTION) .

Necessary preliminary tasks:

Switch off ignition.
Disconnect BATTERY EARTH LEAD .

IMPORTANT: Follow instructions for REMOVING AND INSTALLING CONTROL UNITS

Replacement:

Carry out programming/encoding.
If no data can be read out from the previous control unit, carry out injection quantity compensation (description at end of instructions).

IMPORTANT: It is absolutely essential to read out the fault memory with the BMW diagnosis system and to create a fault memory printout.

Switch off ignition.

Release bolts along line (1).

Tightening torque 12 90 1AZ .

Remove electronics box cover.

Fig 1: Identifying Control Unit Bolts (DME)

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Fig 2: Removing Control Unit Locks

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Unlock battery positive lead (1), detach and lay to one side.

Release locks (2) in direction of arrow and pull control unit upwards slightly.

Pull control unit (1) upwards slightly until plug (2) can be released from control unit in direction of arrow.

Unlock plug (2) and detach from control unit (1).

Fig 3: Removing Control Unit Plug Connection

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Lift out control unit (1).

Fig 4: Removing Control Unit

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Fig 5: Identifying Injector Adjustment Value

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Injector adjustment:

If the DME control unit has been replaced, it will also be necessary to carry out adjustment of the injectors!

Injector adjustment is carried out with the aid of so-called adjustment values.

The adjustment values are printed in two blocks of three digits on each injector.

The adjustment values must be stored in the new control unit!

If injector adjustment is not carried out, the engine may run roughly or fail to start.

Read off the adjustment values and enter according to the installation location (cylinder) of the injectors:

Connect BMW diagnosis system
Identify vehicle
Select "Function selection"
Select "Service functions"
Select "Engine electronics"
Select "Adjustment function"
Select "Adjust injectors"
Select "Test schedule"
The adjustment value must be entered for each cylinder.

Fig 6: Identifying Injector Adjustment Values

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NOTE: Check stored fault message.
Delete fault memory.