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

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

Necessary preliminary tasks:

IMPORTANT: Follow instructions for REMOVING AND INSTALLING CONTROL UNITS .

Replacement:

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

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.

Slacken nut (1).

Release screw (2).

Remove heat shield (3).

Fig 1: Identifying Heat Shield, Screw And Nut

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Release screws (1).

Tightening torque 12 90 2AZ .

Remove electronics box cover (2).

Fig 2: Identifying Electronics Box Cover And Screws

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Unlock all plugs (1) from control unit and disconnect.

Unclip grommet holding-down element (2) and remove.

Release rubber grommets (3) from electronics box. Lay wiring harnesses to one side.

Installation:

Make sure grommets are correctly seated (watertightness).

Fig 3: Identifying Rubber Grommets, Grommet Hold-Down Device And Connectors

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Release outer locks on electronics box at front and rear.

Remove cover (1) from control unit.

Fig 4: Identifying Control Unit Cover

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Lift out control unit (1).

Installation:

Replacement:

Modify holder (2).

Fig 5: Lifting Out Control Unit

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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!

Fig 6: Identifying Injector Adjustment Value

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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:

NOTE: Check stored fault message.
Now clear the fault memory.

Fig 7: Identifying Injector Adjustment Value

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