A4 Mk2
→ The display of fault reader VAS 5051 will show the control unit identification and coding -2-.
|
|
|
|
→ The display on vehicle diagnostic, test and information system VAS 5051 will show the control unit identification and the coding -2-.
|
|
|
|
Note: Item -1- in the illustration shows the engine control unit with protective metal casing. |
→ As a deterrent against unauthorised access to the connectors on the engine control unit, the control unit -1- is bolted to a metal casing -4- by means of shear bolts -3- and a locking plate -2-. The threads of the shear bolts are additionally coated with a thread-locking compound to make them more difficult to remove. In order to unplug the connectors from the engine control unit (for instance when connecting the test box or replacing the control unit), the control unit must be separated from the protective casing. The required procedure is described below: The following tools are required: |
Procedure: Caution
Keep exactly to the following procedure to avoid damage (burning) to the wiring, connectors, insulation or the control units. Follow the operating instructions supplied with the hot-air blower. |
|
Note: In the next step the blower is used to heat the threads for the shear bolts in the locking plate. This reduces the effect of the thread-locking compound so the bolts can then be removed more easily. Warning
When the threads in the locking plate are heated up, this also heats the shear bolts and parts of the metal casing. Take care not to burn your hands. Also make sure that, as far as possible, you only apply heat to the threads and not to the adjacent parts. Cover these up if necessary. |
|
Repeat the procedure for the second shear bolt. Be particularly careful here because the control unit connectors are very close to this bolt. |
|
The engine control unit can now be separated from the metal casing.
Installing After competing repair, install metal casing on engine control unit. Use new shear bolts. Install in reverse sequence; note the following points: The following step needsto beperformed after connecting the new engine control unit:
For this step use vehicle diagnostic, testing and information system VAS 5051. |