Central Locking System

Fault symptom
The central locking system does not work.







Diagnostic procedure
1 Check the operation of the central locking system
- Connect an Intelligent Saab Tester (ISAT) scan tool,
- Select "READ VALUES".
- Select "LOCK SIGNAL" or "UNLOCK SIGNAL".
- Lock or unlock the central locking system using the door key lock.

The ISAT scan tool should display "INACTIVE" when the key is in its normal position and "ACTIVE" when the key is turned.
Does it display correct readings for the locked and unlocked central locking system?
[YES] Continue with point 5.
[NO] Continue with point 2.







2 Check the operation of the central locking system
- Unplug connector H22-1.
- Select "LOCK SIGNAL" or "UNLOCK SIGNAL".

When the connector is unplugged the ISAT scan tool should show "INACTIVE".
Does the ISAT scan tool show "INACTIVE"?
[YES] Continue with point 3.
[NO] Unplug connector H22-2 and enter the same ISAT scan tool command again. When the connector is unplugged the ISAT scan tool should show "ACTIVE".

3 Check the voltage levels
- Connect a BOB.
- Check the voltage by taking readings across:
- pins 17 and 13 of the control module when locking the central locking system.
- pins 6 and 13 of the control module when unlocking the central locking system.

The voltage reading obtained should be about 7 V to battery positive (Batt+) and dip to about 0 V for 750 ms. See the test readings for pins 17 and 6 of the control module connectors.
Is the voltage reading OK?
[YES] Continue with point 5.
[NO] Continue with point 4.







4 Check the wiring
Check the wiring harness for continuity between:
- pin 17 of the control module and
- connector H22-1, pin 21 (LHD)
- connector H22-2, pin 21 (RHD)
- pin 6 of the control module and
- connector H22-2, pin 19 (LHD)
- connector H22-1, pin 19 (RHD)

The resistance should be < 1 ohm.
Is the resistance OK?
[YES] Continue with point 5.
[NO] Repair or replace the wiring harness.

5 Final test
Check to see if the fault symptom persists.

Does the trouble persist?
[YES] Continue as described in "Before Changing the Electronic Control Module". Before Changing the Electronic Control Module
[NO] The remedial measure taken was correct or the fault is of intermittent nature.