Wiring and Component Check With Test Box Adapter Cable VAG 1598/31
Wiring and Component Check with Test Box Adapter Cable VAG 1598/31
• The test box VAG 1598 / 31 is designed in such a way that it can be connected simultaneously to the engine control module wiring harness and to the engine control module itself.
• This has the advantage that the electronic motor control system remains fully functional when the test box is connected (for example, for measuring signals when the engine is running).
• Whether the engine control module has to be connected to the test box or not is described in the respective test procedures.
• Always use test leads from adapter set V.A.G 1594 for connection of testers to test box V.A.G 1598/31.
CAUTION!
To prevent damage to the electronic components, select the appropriate measuring range before connecting the test leads and observe the test requirements.
Connecting test box Adapter Cable (121-point) (VAG 1598/31)
- Switch ignition off.
- Remove rubber seal in direction of - arrow -.
- Remove plenum chamber cover - 1 - to front.
- Pry off two caps - 3 - using screwdriver.
- Loosen hex nuts - 4 - by several turns.
- Loosen wiper arms - 2 - from wiper shaft by tilting slightly.
- Remove hex nuts and detach wiper arms.
- Remove securing clips - 1 - and detach cowl panel grille - 5 -.
- Remove cover for electronics box in plenum chamber - arrows -.
- Carefully pry off fastener - arrow -) using screwdriver.
• Item - 1 - in illustration shows engine control module with protective enclosure.
To render access to the connectors on the engine control module more difficult, the engine control module - 1 - is bolted by the way of a catch - 2 - and shear bolts - 3 - to a protective enclosure - 4 -.
Locking fluid is applied to thread of shear bolts to make bolts more difficult to remove.
Engine control module must be separated from protective enclosure to disconnect connectors from engine control module (e.g. when connecting up test box or replacing engine control module). This procedure is described in the following.
Tools required:
• Hot-air blower - 1 - (from wiring-harness repair set VAS 1978)
• Nozzle attachment - 2 - (also from wiring-harness repair set VAS 1978)
• Commercially available locking pliers
Procedure:
CAUTION!
To avoid damaging (scorching) wires, connectors, insulation and control modules, always adhere to the following operations and observe operating instructions for hot-air blower.
- Tilt engine control module with protective enclosure toward engine compartment so the catch (item - 2 -) becomes visible, and place a clean cloth beneath engine control module with protective enclosure.
- Make settings on hot-air blower as shown in illustration, i.e. set temperature potentiometer - 2 - to max. heat output and two-stage air flow switch - 3 - to position 3.
• Then use hot-air blower to heat thread of catch into which shear bolts are screwed. This operation is designed to reduce the inhibiting action of the locking fluid on the shear bolt thread to make it easier to screw out the shear bolts afterward.
CAUTION!
Heating the thread of the catch also greatly increases the temperature of the shear bolts and protective enclosure components. Take care to avoid burns. Make sure that only the thread is heated and none of the surrounding components if at all possible (these should be covered if necessary).
- Direct nozzle - 1 - of hot air blower onto thread of catch, so that nozzle "encloses" thread. Nozzle can safely be allowed to contact upper end of metal housing.
- Switch on hot-air blower and heat thread for approx. 20 to 25 seconds.
- Then grip bolt head - 2 - with locking pliers - 1 - and screw out shear bolt in direction of - arrow -.
Use the same procedure for the second shear bolt, taking particular care to avoid the control module connectors in the immediate vicinity.
- Direct nozzle - 1 - of hot air blower onto thread of catch again, so that nozzle "encloses" thread. Nozzle can safely be allowed to contact upper end of metal housing.
- Switch on hot-air blower and heat thread for 20 to 25 seconds.
- Then grip bolt head - 2 - with locking pliers - 1 - and screw out shear bolt in direction of - arrow -.
Engine control module can now be separated from protective enclosure.
- Release connectors of engine control module and disconnect.
- Connect test box V.A.G 1598/31 to wiring harness connector. Ground clip - arrow - must be connected to ground (GND). Whether or not engine control module is additionally to be connected to test box is indicated in the appropriate test sequences.
- Perform testing as described in appropriate repair operations.
Installing engine control module
Install in reverse order of removal; protective enclosure is always to be reinstalled to engine control module. Use new shear bolts.
- Check Diagnostic Trouble Code (DTC) memory and erase, if necessary.