12 14 550 Replacing control unit (DME) (N20, N26)

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2016 BMW 328i xDrive, 2016 BMW 328d xDrive, 2015 BMW 328i xDrive, 2015 BMW 328d xDrive, and 2014 BMW 328i xDrive. 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 damage (ESD protection)

Necessary preliminary tasks:

Switch off ignition.
Disconnect BATTERY NEGATIVE LEAD .
Remove ACOUSTIC COVER

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.

Unlock and pull off all connectors (1) from the DME control unit (2).

Release screws.

Tightening torque 12 14 1AZ .

Remove DME control unit.

Fig 1: Locating DME Control Unit Connectors

Courtesy of BMW OF NORTH AMERICA, INC.

Injection quantity compensation:

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

Injection quantity compensation is carried out with the aid of so-called adjustment values.

The adjustment value is printed on each injector in three digits.

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

If injector quantity compensation 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 plan"
The adjustment value must be entered for each cylinder.

Fig 2: Identifying Injection Quantity Compensation Value
Courtesy of BMW OF NORTH AMERICA, INC.

NOTE: Check stored fault message.
Delete fault memory.