Removing and installing engine control unit J623 and engine control unit 2 J624 — VW

Removing and installing
engine control unit
J623
and
engine control unit 2
J624
Note
If the engine control unit is to be replaced, connect vehicle diagnosis tests and carry out the guided function
“Replacing engine control unit”
. In this guided function, important adaptation values are read out of the old engine control unit and transferred to the new engine control unit.
The two engine control units have identical plug-in connectors. However, it must be ensured that they are not mixed up with each other.
Special tools and workshop equipment required
Hot air blower from
wiring harness repair set
VAS 1978 B
Nozzle attachment from
wiring harness repair set
VAS 1978 B
Grip pliers
Removing:
Switch off ignition.
Remove windscreen wiper arms
Electrical system
Rep. gr.
92
Windscreen wiper system; Removing and installing wiper arms
.
Remove right plenum chamber cover
General body repairs, exterior
Rep. gr.
50
Plenum chamber cover
.
Cover engine compartment in the area of the engine control unit in order to prevent paintwork from being scratched.
Unscrew bolt
1
and nut
2
. Take out
engine control unit 2
J624
upwards.
Remove bolts
1
and unclip wiring harness
2
. Remove nuts
3
and remove bracket
A
.
Carefully remove
engine control unit
J623
upwards out of the plenum chamber.
Note
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.
Caution
Make sure that no components are damaged due to burning.
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.
Heat shear-head bolt
arrow
with the help of a hot-air blower.
Fit clamping pliers to end of bolt
1
and loosen bolt.
Bend metal edges
2
of protective housing downwards and unscrew bolt.
Remove the other shear-head bolts in the same way.
Installing:
Replace protective housing.
Install new protective housing with new shear-head bolts.
Evenly tighten shear-head bolts until bolt heads shear off.
First, insert
engine control unit
J623
into plenum chamber.
Then, insert
engine control unit 2
J624
into plenum chamber.
Firmly bolt on brackets for engine control units.
Install plenum chamber cover
General body repairs, exterior
Rep. gr.
50
Plenum chamber cover
.
Install wiper arms
Electrical system
Rep. gr.
92
Windscreen wiper system; Removing and installing wiper arms
.