SEAT Workshop Service and Repair Manuals

Engine control unit -J623- with locking device type II: Removing and installing Consult the equivalence table for tools and equipment according to applicability among Seat / VW / Audi / Skoda → Chapter. Special tools and workshop equipment required

t  Electric knife -SAT 1561-, see equivalent → Anchor

t  Wiring harness repair set -VAS 1978A-, see equivalent → Anchor t  Pliers Engine control unit -J623- with locking device type II: Removing → Anchor Engine control unit -J623- with locking device type II: Fitting → Anchor

Removing: –  Release clip -arrow- and remove engine control unit -J623-.   Note Cover painted surfaces with a cloth to prevent scratching.

To help prevent unauthorised access to the connectors on the engine control unit, the control unit is secured by means of shear bolts to a locking plate and a metal casing.

The threads of the two shear bolts -4- which are not screwed into the engine control unit are secured with locking fluid. This is why these screws must be heated using a hot air blower to enable them to be unscrewed.

The threads of the two shear bolts -3- which are screwed into the engine control unit are not secured with locking fluid. Do not apply heat to the threads in the control unit housing; this is not necessary and would cause overheating of the control unit.

Adjust the settings on the hot air gun as shown in the fig., i.e. the potentiometer for the temperature setting -2- on the maximum heating line and the two level switch for air quantity -3- on position 3.   WARNING Heating the thread of the locking plate also heats up the shear bolts and parts of the metal housing. Risk of burn injuries! It is also important to ensure that only the thread is heated and none of the surrounding components if at all possible. If necessary, cover these parts.

–  Heat the thread of the shear bolt on the connecter side for about 25 to 30 seconds. –  Unscrew shear bolts using suitable vice-grip pliers (see arrow in illustration).

–  The two shear bolts screwed into the engine control unit do not need to be heated. They must be removed without being heated. –  Detach metal locking plate from control unit connectors. –  Disengage and remove the engine control unit -J623- connector. –  Remove engine control unit -J623-. Installing Install in reverse order to dismantling, noting the following: –  After installation, the locking plate must be re-fitted on the engine control unit -J623-. –  Remove the remains of the threadlocker from the breakaway bolt holes. The threads can be cleaned with a thread tap. –  Always use new shear bolts. –  Install the cover of the plenum chamber → Cover of the plenum chamber: removing and installing ; Rep. gr.55 –  Activate engine control unit via vehicle diagnostic, testing and information system -VAS 505X- in „Guided Functions“ mode, „Replace engine control unit“. –  Take vehicle for a test drive.