If No Diagnosis Is Possible
NO DIAGNOSIS POSSIBLEIf the System Tester 9288 cannot enter the diagnosis, check the following Items:
- Check adapter lead 9288/1 for continuity
- Check K and L wire on adapter lead 9288/1 for continuity.
- Connector on tester
- Socket 3 = L wire
- Socket 7 = K wire
- Socket 3 (8-pin connector) to pin 7 (19-pin connector)
- Socket 7 (8-pin connector) to pin 8 (19-pin connector)
^ Check voltage supply
Check ground and terminal 15 on adapter lead 9288/1 for voltage supply.
Connector on tester
Socket 4 = Ground
Socket 5 = Terminal 15
Check K and L wires with oscilloscope and Special Tool 9540
Checking L wire:
Pull connector 2 (yellow) off the alarm control unit. Connect Special Tool 9540 between alarm control unit and connector 2. Connect oscilloscope to socket 14 (L wire) of Special Tool 9540. Check L wire. To do this, switch on ignition and System Tester 9288 and start diagnosis (energizing).
Checking K wire:
Same procedure as for L wire, but use socket 15 for K wire instead of socket 14 for L wire.
NOTE: If the signals displayed deviate from the specifications, this may be due to interference generated by a control unit connected to the K or L wire (for diagnosable systems, refer to wiring diagram). Pull one connector after another off the control units and repeat checking the K and L wires. Start with the alarm control unit as described below. If the last control unit has been disconnected, one of the control units that had been disconnected must be reconnected again. Otherwise no signal can be generated anymore.
NOTE: The on-board computer (rev counter) is connected to the K and L wires but is not diagnosable. It may cause interferences, however!
CAUTION: If the airbag control unit is disconnected, power supply to term. 15 of the DME control unit is interrupted.
^ Disconnect alarm control unit and install jumper
- Pull connector 1 (black) off the alarm control unit.
- Connect jumper to connector 1 of the alarm control unit, pin 4 and pin 6.
- Check signals of the K and L wire again as described above
^ Disconnect other control units.
- Disconnect next control unit, switch on ignition.
- switch tester off and on again and start diagnosis (energize again).
- Check signals of K and L wire.
- Repeat procedure until all control units have been disconnected.
^ Check K and L wires for short to ground
^ Check all control units for continuity to diagnosis socket