12 14 550 Replacing control unit (DME)

WARNING: This page is about a different car, the 2010 BMW 135i, 2009 BMW 135i, and 2008 BMW 135i. However, it is still accessible from the selected car via links, so may be relevant.

Necessary preliminary tasks:

Switch off ignition
Disconnect battery . See 61 20 900 DISCONNECTING AND CONNECTING BATTERY NEGATIVE LEAD .
Remove microfilter housing . See MICROFILTER .

IMPORTANT: Follow instructions for removing and installing control units

IMPORTANT: Read and comply with notes on protection against electrostatic damage (ESD protection). See 61 35... NOTES ON ESD PROTECTION (ELECTRO STATIC DISCHARGE) .

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 MoDiC or the BMW DIS and to create a fault memory printout.

Switch off ignition.

Unlock fasteners (1) from below and slide upwards approx. 10 mm.

Unlock locks (2) in direction of arrow.

Remove cover (3).

Fig 1: Unlocking Locks

Courtesy of BMW OF NORTH AMERICA, INC.

Unlock plug (1) and remove.

Release grommet (2) from electronics box.

Installation:

Make sure grommet (2) is correctly seated in housing (watertightness).

Unlock control unit (3) and raise slightly.

Fig 2: Identifying Plug, Grommet And Control Unit

Courtesy of BMW OF NORTH AMERICA, INC.

Unlock plugs (1) using slide in direction of arrow and remove.

Remove control unit (2).

Installation:

Replacement:

Note device identification number and coding.

Fig 3: Unlocking Plugs

Courtesy of BMW OF NORTH AMERICA, INC.

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 4: Identifying Adjustment Values On Injector

Courtesy of BMW OF NORTH AMERICA, INC.

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 DIS Tester
Identify car
Select "Function selection"
Select "Service functions"
Select "Engine electronics"
Select "Adjustment programs"
Select "Adjust injectors"
Change "Test schedule"
The adjustment value must be entered for each cylinder.

Fig 5: Identifying Adjustment Value On Cylinder

Courtesy of BMW OF NORTH AMERICA, INC.

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