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

Removing and installing
engine control unit
J623
with protective housing, CC
Special tools and workshop equipment required
Hot air blower
VAS 1978/14A
item 1
with nozzle
2
from
wiring harness repair set
VAS 1978 B
Grinder e.g.
axial grinder, straight
VAS 6682
Vehicle diagnostic tester
Note
If the engine control unit is to be replaced, connect the
vehicle diagnostic tester
and carry out the guided function
“Renewing engine control unit”
.
The shear-head bolt threads may coated with locking compound. To simplify removing, the shear-head bolts can be heated using
hot air blower
VAS 1978/14
. When doing this, ensure that no adjacent cables, connectors or components are damaged!
Removing
If the engine control unit is to be renewed, switch on ignition, and select the following menu options on
vehicle diagnostic tester
:
01 - Engine electronics
Guided functions
01 - Renew engine control unit
Switch off ignition and remove ignition key.
Remove wiper arms
Electrical system
Rep. gr.
92
Removing and installing wiper arms
.
Remove plenum chamber cover
General body repairs, exterior
Rep. gr.
50
Plenum chamber cover
.
Detach wiring harness for engine control unit from inner side of plenum chamber bulkhead.
Remove plenum chamber bulkhead
General body repairs, exterior
Rep. gr.
50
Plenum chamber bulkhead
.
Release feed-through for wiring harness
arrow
, and pull it off upwards.
Detach wiring harness for engine control unit.
Release and pull off connector on wiper motor
Electrical system
Rep. gr.
92
Windscreen wiper system; Removing and installing windscreen wiper system
.
Pull engine control unit as far as possible towards front right wheel housing.
Detach engine control unit from plenum chamber.
Push down retaining frame in direction of
arrow
and remove engine control unit.
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.
Set hot air blower as shown in illustration.
Potentiometer for temperature adjustment
2
set to maximum heat output.
Two-stage switch for air flow rate
3
set to position 3.
Note
Risk of damage to adjacent components caused by hot air blower. Risk of overheating.
Cover surrounding components.
Heat head of shear bolt
1
for approx. 20 to 30 seconds.
Unscrew shear bolt
1
using screwdriver
2
.
Remove protective housing from
engine control unit
J623
.
Unscrew shear-head bolts
arrows
using a pair of pliers.
Insert screwdriver between both locking plates
arrow
.
Carefully push screwdriver in
direction of arrow
.
At the same time, bend locking bar
1
upwards.
Bend locking bar
1
in
direction of arrow
until it can be pulled off connector.
Push locking devices of connectors in
direction of arrow
and pull off connectors.
Installing
Fit connectors to engine control unit.
Push locking devices to stop in
direction of arrow
.
Fit retaining bar
1
onto connectors and press it in direction of
arrow
.
Guide pin
2
to stop into hole on engine control unit.
Use new shear-head bolts
arrows
to secure retaining bar on engine control unit.
Evenly tighten shear-head bolts until bolt heads shear off
arrows
.
Insert engine control unit into retaining frame and push retaining frame upwards in direction of
arrow
.
Install plenum chamber bulkhead, plenum chamber cover and wiper arms
General body repairs, exterior
Rep. gr.
50
Plenum chamber bulkhead
.
Install wiper arms and plenum chamber cover
General body repairs, exterior
Rep. gr.
50
Bulkhead; Removing and installing plenum chamber cover
.