Renewing Motronic control unit J220 — AUDI

Renewing
Motronic control unit
J220
Removing
If the
motronic control unit
J220
is to be renewed, you must first print out the control unit identification and coding before removing it.
Connect
vehicle diagnostic, testing and information system
VAS 5051B
and select vehicle system
“01 - Engine electronics”
from list. When doing this, the ignition must be switched on.
The display on
vehicle diagnostic, testing and information system
VAS 5051B
will show the control unit identification and the coding
2
.
Always start by displaying the control unit identification and coding and printing it out.
Switch off ignition.
Lever off caps on windscreen wiper arms with a screwdriver.
Loosen hexagon nuts
arrow
several turns.
Loosen wiper arms from wiper shafts by tilting slightly.
Completely remove hexagon nuts and detach wiper arms from wiper shafts.
Unclip washer jets
arrow
.
Push washer jets through assembly opening back into plenum chamber, leaving hoses connected.
Pull off rubber seal
1
from plenum chamber cover.
Detach plenum chamber cover
2
.
Bracket for engine control unit: version 1
Bracket for engine control unit: version 2
Release clip
“arrow”
and remove engine control unit. You can then unplug the connector from the engine control unit.
The following steps are only required if the engine control unit is installed as in version 1 in the illustration.
Set wiper shafts to service position (to enable electrical connector to be detached from engine control unit).
First close bonnet.
Switch ignition on and then off again. Within 10 seconds, press wiper switch down once to brief wipe position.
Note
The wiper shafts will now run to the service position.
Then open bonnet again.
The following steps are only required up to and including model year 2006.
Remove ignition key.
To make it more difficult to access connectors on engine control unit, the engine control unit is covered by a protective housing
1
and secured with shear bolts
2
.
To make it more difficult to unscrew the shear bolts, their threads have been coated with locking fluid.
Engine control unit must be separated from protective housing before connectors can be unplugged from engine control unit (e.g. when connecting test box or replacing engine control unit). This procedure is described in the following.
Special tools and workshop equipment required
Hot air blower
1
(from the
wiring harness repair set
VAS 1978A
)
Nozzle attachment
2
(also from
wiring harness repair set
VAS 1978A
)
Commercially available vice-grip pliers
Procedure:
WARNING
The following procedure must be followed exactly to prevent any damage (scorching) to wiring, connectors, insulation and control units. Observe operating instructions for 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.
Note
Then use hot air blower to heat shear bolts. This step reduces inhibiting action of locking fluid on shear bolt threads and makes it easier to unscrew these bolts.
Cover up all painted parts to avoid any damage caused by hot air blower or vice-grip pliers.
WARNING
Parts of the protective housing will become very hot as a result of heating the shear bolts. Take care to avoid burns. Try to ensure that only the shear bolt is heated and none of the nearby components. These should be covered if necessary.
Place the hot air blower nozzle close to the shear bolt on the protective housing.
Switch on the hot air blower and heat the bolt for approximately 20 to 25 seconds.
Then grasp the bolt head with the vice-grip pliers and unscrew the shear bolt.
The procedure for the second shear bolt is exactly the same.
Engine control unit can now be separated from protective housing.
Release front connector
1
from engine control unit and unplug.
Pull engine control unit out of retainer
arrow
(wiper shafts in service position).
Release rear connector on engine control unit and unplug.
Installing engine control unit on vehicles with protective housing
Installation is performed in the reverse sequence.
Make sure you fit protective housing back on engine control unit.
Clean threaded holes for shear bolts to remove any residue from locking fluid. This can be done using a thread tap.
Use new shear bolts.
Return wiper arms to normal position.
First close bonnet.
Switch on ignition and press wiper switch down once to brief wipe position. The wipers will then return to the normal position.
The following step must be performed after installing the new engine control unit:
Activate engine control unit in
“Guided Fault Finding”
under the test procedure / function
“Replace engine control unit”
.