Volkswagen Golf Service & Repair Manual: Removing and installing engine control unit -J623- (with protective housing)
| 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- |
| Small grinder (commercially available) |
| Vehicle diagnostic tester |
| – |
If engine control unit is renewed, select test
sequence/function Replace engine control unit on “vehicle
diagnostic tester” in “Guided functions” mode. |
| – |
Switch off ignition and remove ignition key. |
 Note
|
t |
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 system; Rep. gr.27. |
|
|
|
| To remove protective housing -1-,
unscrew shear bolts -arrows- as
follows: |
Note
| Cover the area around the engine control unit, and protect
it from flying sparks. |
|
|
|
| – |
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. |
| – |
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. |
Risk of damage to adjacent components caused by hot air blower. Risk of
overheating.If necessary, cover adjacent components. |
|
|
| – |
Heat head of shear bolt -1- for
approx. 20 to 30 seconds. |
|
|
|
| – |
Unscrew shear bolt -1- using
screwdriver -2-. |
|
|
|
| – |
Release fastener -arrow- and
detach engine control unit -1-. |
| – |
Release and unplug connectors for engine control unit
-J623-. |
| 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). |
| – |
Use new shear-head bolts. |
| After having installed the new engine control unit, the
following work must be carried out: |
| – |
Connect battery
→ Electrical system; Rep. gr.27. |
| – |
Connect vehicle diagnostic tester. |
| – |
Switch on ignition and select the following menu options on
vehicle diagnostic tester: |
| 01 - Renew engine control unit |
|
|
|
Special tools and workshop equipment
required
Hot air blower -VAS 1978/14A--1-
with nozzle -2- fr ...
Other materials:
Anti-corrosion treatment
Caution
Missing anti-corrosion treatment results in damage
to the onboard supply.
Note
All threaded connections must be tightened to specified
torque.
...
Fitting wheel, fitting instructions for Audi
Vehicles with tyre pressure sensor
If the wheels are changed (e.g. switch from summer to winter
tyres), the wheel electronics transmit data as soon as the speed
of the new wheels exceeds 25 km/h. The new wheel electronics' ID
numbers are ...
Safety precautions when working on fuel supply system
Risk of injury due to highly-pressurised fuel.
The fuel system is under high pressure. Risk of injury due to fuel
which may spurt out.
–
Release high pressure before opening the fuel system.
& ...
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Removing and installing engine control unit -J623- (with metal locking
plate)
Exhaus system