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

Removing and installing
engine control unit
J623
, engine control unit with protective housing
Removing
To remove protective housing
1
, unscrew shear-head bolts
arrows
as follows:
Make groove (for a screwdriver) in head of shear-head bolt
1
using a small grinder
2
.
Note
The threads of the shear-head bolts are secured with locking fluid. To unscrew these bolts, the threads must therefore be heated with the hot air blower.
Select settings on hot air blower as shown in figure, i.e. set temperature potentiometer
2
to maximum heat output and two-stage air flow switch
3
to position 3.
WARNING
Risk of burns from hot air blower.
When heating up the thread of the locking element, the shear-head bolts and parts of the sheet-metal housing become hot as well. Ensure to only heat up the thread and no surrounding components. Cover surrounding components, if necessary.
Heat head of shear-head bolt
1
for approx. 20 to 30 seconds.
Unscrew shear-head bolt
1
using screwdriver
2
.
Caution
If the engine control unit comes into contact with the positive battery terminal, the engine control unit will be destroyed. For this reason, the battery always needs to be disconnected prior to removing the engine control unit from its bracket
Electrical system
Rep. gr.
27
Battery; Disconnecting and connecting battery
.
Release fastener
arrow
and detach engine control unit
1
.
Release and pull off connectors for
engine control unit
J623
.
Installing
Installation is carried out in the reverse order; note the following:
It is essential that the
engine control unit
J623
be provided with the protective housing again.
Remove any locking compound residues from the threaded holes for the shear-head bolts. Threads can be cleaned using a tap (thread cutter).
Always use new shear bolts.
After having installed the new engine control unit, the following work must be carried out:
Use
Vehicle diagnostic tester
to activate engine control unit.
Self-diagnosis-capable systems
0001 - Engine electronics
0001 - Engine electronics, functions
0001 - Renew engine control unit