12 14 552 Replace Control Unit (DME) Cylinders 1-6

12 14 552 Replace Control Unit (DME) Cylinders 1-6 (N74)







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







Necessary preliminary tasks:
- Turn off ignition
- Disconnect battery negative lead
- Drain coolant for intercooler
- Remove right intake manifold

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.







Release screw (1).
Lay filler neck (2) for windscreen washer fluid to one side.







Release screws (1).
Tightening torque 12 90 2AZ.
Remove electronics box cover (2).







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).







Release outer locks on electronics box at front and rear.
Remove cover (1) from control unit.







Release screws (1).
Tightening torque 12 90 1AZ.
Unclip coolant lines at retainer (2) from electronics box.
Release electronics box (3) from spring strut, do not remove.







NOTE: Picture shows rear coolant line on control unit, procedure for front is identical.

Press in lock (2) and detach coolant line (1) from control unit.
Catch and dispose of escaping coolant.
Lift out control unit.







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







NOTE:
Check stored fault message.
Delete fault memory.
Vent cooling system for intercooler.