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Home >> BMW >> 1997 >> 540i Standard >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Engine Electrical System - Repair Instructions >> Electronic Switching Or Control Unit >> 12 14 550 Replacing control unit (DME) (M52, M62, M54)

12 14 550 Replacing control unit (DME) (M52, M62, M54)

Follow instructions for removing and installing electronic control units.

Read fault memory.

Turn off ignition.

Before replacing the control unit, comply with the following instructions:

Open locking bracket (1). Open cover on filter and unhook from hinges.

Detach rubber seal (2).

Installation 

Hook cover of filter housing into hinges in correct position.

Incorrect installation leads to sealing problems.

Fig 1: Detaching Rubber Seal
G03152849Courtesy of BMW OF NORTH AMERICA, INC.

Remove retaining clip (3).

Lift out filter housing (4).

Fig 2: Removing Filter Housing
G03152850Courtesy of BMW OF NORTH AMERICA, INC.

Release screws (1).

Tightening torque, see 12 90 4AZ in ENGINE ELECTRICAL SYSTEM - TIGHTENING TORQUE .

Fig 3: Releasing Screws Of Control Unit
G03152851Courtesy of BMW OF NORTH AMERICA, INC.

From 10/2000: 

NOTE: For purposes of clarity, locking clips (1) are shown with cover opened.

After releasing screws, unlock both locking clips (1) and remove cover.

Fig 4: Identifying Locking Clips
G03152852Courtesy of BMW OF NORTH AMERICA, INC.
  1. Control unit of Digital Motor Electronics:

    Unlock plug connections and detach from DME control unit. Remove DME control unit from retaining clips.

  2. Control unit for automatic transmission
Fig 5: Identifying Control Unit Of Digital Motor Electronics
G03152853Courtesy of BMW OF NORTH AMERICA, INC.
NOTE: Interrogate fault memory of DME control unit.
Check stored fault messages.
Rectify faults.
Then clear fault memory.