Volkswagen Workshop Service and Repair Manuals

Removing and installing anti-theft engine control unit Special tools and workshop equipment required t  Grip pliers

t  Hot air blower from wiring harness repair set -VAS 1978-   Note t  If the engine control unit is to be renewed, connect vehicle diagnostic, testing and information system -VAS 5051B- and perform „Renewing engine control unit“ in guided functions. t  The shear-head bolt threads are coated with locking compound. Heating the shear-head bolt with a hot air blower releases the locking effect of the locking compound. Removing: –  Switch off ignition. –  Remove wiper arms, plenum chamber cover and plenum bulkhead → Electrical system; Rep. gr.92.   Caution Cover lines, connections and control units in the vicinity of the engine control unit to prevent damage through heat (scorching/melting of plastics etc.). Perform settings on hot air blower -4- as shown:

–  Turn temperature settings potentiometer -2- to a maximum heat output of 600 °C. –  Set two-stage switch for volume of air -3- to position 3.   WARNING When shear-head bolts are heated up, parts of the protective housing will be subjected to a large amount of heat. Wear protective gloves to avoid possible injury. –  Place nozzle of hot air blower close to shear-head bolt. –  Switch on hot air blower and heat the bolts. –  Remove bolts with grip pliers.   Note

If the bolts will not move, saw into heads of shear-head bolts so that two parallel slots are created -arrows- and then remove the bolts.

–  Insert a screwdriver between protective housing -A- and bracket -arrow-.

–  Lever up protective housing using screwdriver -A- and pull to side off bracket -arrow-.

–  Bend catch open slightly -1-. –  Then push engine control unit out of retainer -arrow-. –  Now release connector on engine control unit and pull off connector. Installing: –  Fit connector to engine control unit and lock connector in position. –  Push engine control unit onto bracket.

–  Press catch -1- against engine control unit. –  Push protective housing onto bracket.

–  Tighten new shear-head bolts -1- evenly until heads shear-head off. –  Install plenum chamber bulkhead, plenum chamber cover and wiper arms → Electrical system; Rep. gr.92.