Removing and installing engine control unit J623 (with protective housing) — VW

🧭 Before you start

Fits: VW Golf VII Variant (BA), VW Golf Sportsvan (AM1, 2014–2020), VW Golf VII (5G, 2012–2020), VW Passat B8 (3G, 2014–), VW Touran II (5T, 2015–)

• Renewed: shear-head bolts

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• The threads of the shear bolts are secured with locking fluid. To unscrew these bolts, the threads must therefore be heated with the hot air blower.

🔧 Engine codes this applies to

📐 34 workshop diagrams for CHPA

Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.

📋 Procedure

1. If the engine control unit is to be renewed, switch on ignition, and select the following menu options on vehicle diagnostic tester:
2. Switch off ignition and remove ignition key. [Note: If the engine control unit comes into contact with the positive battery terminal, the engine control unit will be destroyed.Therefore, the battery must be disconnected before the engine control unit is removed Electrical system27Battery; Disconnecting and connecting battery.] [Note: Cover the area around the engine control unit, and protect it from flying sparks.]
3. Make groove (for a screwdriver) in head of shear bolt (1) using a small grinder (2). [Note: The threads of the shear bolts are secured with locking fluid. To unscrew these bolts, the threads must therefore be heated with the hot air blower.]
4. Select settings on hot air blower as shown in illustration, i.e. set temperature potentiometer (2) to maximum heat output and two-stage air flow switch (3) to position 3.
5. Heat head of shear bolt (1) for approx. 20 to 30 seconds.

6. Unscrew shear bolt (1) using screwdriver (2).
7. Release fastener (arrow) and detach engine control unit (1).
8. Release and unplug connectors for engine control unit J623.
9. It is essential that the engine control unit J623 be provided with the protective housing again.
10. Remove any locking compound residues from the threaded holes for the shear-head bolts. Threads can be cleaned using a tap (thread cutter).
11. Use new shear-head bolts.
12. Connect battery Electrical system27Battery; Disconnecting and connecting battery.
13. Connect vehicle diagnostic tester.
14. Switch on ignition and select the following menu options on vehicle diagnostic tester:

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