Engine Control Module: Service and Repair

12 14 550 Replacing Control Unit (DME) (N55)







IMPORTANT: Read and comply with notes on protection against electrostatic damage (ESD protection).







Necessary preliminary work:
- Switch off ignition.
- Disconnect battery negative lead.
- Remove intake plenum.

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 screws (1).
Tightening torque 12 14 2AZ.







Release screws (1).
Tightening torque 12 14 1AZ.
Remove control unit from intake plenum.







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 value is printed with three digits - depending on the version - on the injector body.
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 plan"
- The adjustment value must be entered for each cylinder.







NOTE:
Check stored fault message.
Delete fault memory.