System Completely Inoperable
C1: Checking Fuses.
Switch off ignition.
Remove fuses 3 and 6.
Check that fuses 3 and 6 in fusebox are intact.
If fuses are faulty:
Temporary overload or fault in central locking system. Replace fuse(s) and check system operation as per C4.
If fuses are Intact:
Check voltage supply (30) to fuse 6 in fusebox as per C2.
C2: Checking Supply (30) To Fuse 6 In Fusebox.
Switch off ignition.
Connect a voltmeter between fuseholder terminal 11/6:1 (fuse 6) and ground. The voltmeter should indicate battery voltage.
If reading is correct:
Check supply (15) to fuse 3 in fusebox as per C3.
If reading is Incorrect:
Open-circuit or short circuit is present in supply lead between fuseholder terminal 11/6:1 and battery 1/1. Correct the fault or replace supply lead between battery and fuseholder. Reinstall fuses.
C3: Checking Supply (15) To Fuse 3 In Fusebox.
Switch off ignition.
Connect a voltmeter between fuseholder terminal 11/3:1 (fuse 3) and ground. The voltmeter should indicate 0 V.
Switch on ignition.
Connect a voltmeter between fuseholder terminal 11/3:1 (fuse 3) and ground. The voltmeter should indicate battery voltage.
If rereadings correct:
Check system operation as per C4
If reading is Incorrect:
Check supply lead between fuse holder terminal 11/3:1 and ignition switch 3/1 for open circuit or short-circuit. Correct the fault or replace the supply lead between ignition switch and fuseholder terminal 11/3:1. Reinstall the fuses.
C4: Checking System Operation
Switch off Ignition.
Reinstall fuses.
Check that the system can be operated from the other front door or from trunk/tailgate.
If central locking can be operated:
Check the ground lead for the front door operating switch C17.
If central locking cannot be operated:
Check the mechanical locking function of all central lock units C5.
C5: Checking Mechanical Locking Function Of All Central Locking Units
Switch off ignition.
Check if front doors and trunk/tailgate can be locked and unlocked with key, and if rear doors can be unlocked by raising the interior locking button and/or opening with inside handle.
If all units can be operated mechanically:
Check ground lead to central locking relay as per C6.
If any unit cannot be operated mechanically:
Mechanical fault is present in central locking unit. Correct the fault or replace the unit.
C6: Checking Central Locking Relay Ground Lead
Switch off ignition.
Remove central locking relay 2/7. Connect an ohmmeter between relay base terminal 31 and ground. The ohmmeter should indicate approx. 0 Ohm.
If reading is correct:
Check supply (30) to central locking relay as per C7.
If reading is Incorrect:
Check ground lead between relay base terminal 31 and electrical distribution unit (31/50) power ground terminal for open-circuit or short-circuit. Correct the fault or replace central locking relay ground lead. Reinstall central locking relay 2/7.
C7: Checking Supply (30) To Central Locking Relay
Switch off ignition.
Connect a voltmeter across relay base terminals 30 and 31.
The voltmeter should indicate battery voltage.
If reading is correct:
Check trigger supply (15) to central locking relay as per C8.
If reading is Incorrect:
Check supply lead between relay base terminal 30 and fuse holder terminal 11/6:2 (fuse 6) for open-circuit or short-circuit to ground. Reinstall central locking relay 2/7.
C8: Checking Trigger Supply (15) To Central Locking Relay
Switch off ignition.
Connect a voltmeter across relay base terminals 15 and 31.
The voltmeter should indicate approx. 0 V.
Switch on ignition.
Connect a voltmeter across relay base terminals 15 and 31.
The voltmeter should indicate battery voltage.
If readings are correct:
Check lead 87 to central locking motors as per C9.
If readings are Incorrect:
Check trigger supply lead between relay base terminal 15 and fuseholder terminal 11/3:2 (fuse 3) for open-circuit or short-circuit to supply. Correct the fault or replace trigger supply lead to central locking relay. Reinstall central locking relay 2/7.
C9: Checking Lead 87 To Central Locking Motors
Switch off Ignition.
Connect an ohmmeter between relay base terminals 87 and 31.
The ohmmeter should indicate infinite resistance.
Connect a voltmeter across relay base terminals 87 and 31.
The voltmeter should indicate 0 V.
If readings are correct:
Check lead 88 to central locking motors as per C10.
If readings are Incorrect:
Check lead between relay base terminal 87 and central locking motors for short-circuit. Correct the fault or replace lead between relay base terminal 87 and central locking motors. Reinstall central locking relay 2/7.
C10: Checking Lead 88 To Central Locking Motors
Switch off ignition.
Connect an ohmmeter between relay base terminals 88 and 31.
The ohmmeter should indicate infinite resistance.
Connect a voltmeter across relay base terminals 88 and 31.
The voltmeter should indicate approx. 0 V.
If readings are correct:
Check operation of central locking motors as per C11.
If readings are Incorrect:
Check lead between relay base terminal 88 and central locking motors for short circuit. Correct the fault or replace lead between relay base terminal 88 and central locking motors. Reinstall central locking relay 2/7.
C11: Checking Operation Of Central Locking Motors
Switch off ignition.
Unlocking
Ground relay base terminal 87 by bridging with terminal 31. Then apply battery voltage to relay base terminal 88 for approx. 2 seconds by bridging with terminal 30. The central locking units should switch to unlocked position.
Locking
Ground relay base terminal 88 by bridging with terminal 31. Then apply battery voltage to relay base terminal 87 for approx. 2 seconds by bridging with terminal 30. The central locking units should now switch to locked position.
If central locking units are activated:
Check operating switch signal leads as per C15.
If central locking units are not activated:
Check central locking motor windings as per C12.
C12: Checking Central Locking Motor Windings
Switch off ignition.
Unlock the trunk/tailgate, filler cover and all doors.
Connect an ohmmeter between relay base terminals 87 and 88. The ohmmeter should indicate 1-15 Ohm
If reading is 1-15 Ohm:
Although central locking motor windings may appear Intact, an individual winding may be faulty. Check motor windings as per C14.
If reading is 0 Ohm:
Check wiring between central locking molars and relay base terminals 87 and 88 for short circuit. Correct fault or replace wiring between relay base terminals 87 and 88 and central locking motors. Reinstall central locking relay 2/7.
If the ohmmeter indicates infinite resistance:
Check the central locking relay's windings as per C13.
C13: Checking Central Locking Relay Windings
Switch off Ignition.
Reinstall central locking relay 2/7. Remove door, luggage compartment or trunk lid panels as necessary. Open the central locking unit connector. Connect voltmeter as follows:
Front doors: between terminals 10 and 12 in the harness's 14-pin connector.
Rear doors: between terminals 3 and 4 in the harness's 8-pin connector.
Trunk lid: between terminals 6 and 7 in harness's 8-pin connector.
Filler cover: between terminals 1 and 2 in harness's 2-pin connector.
Voltmeter should read approx. 0 V in all measurements.
If readings are correct:
Check central locking motor winding as per C14.
If any reading is Incorrect:
Fault in central locking relay windings.
Trace the fault in the interior light ground lead as per C21.
C14: Checking Central Locking Motor Windings
Switch off Ignition.
Remove central locking relay 2/7.
Remove relevant panels in doors, luggage compartment or trunk lid. Open central locking unit connector.
Connect ohmmeter as follows:
Front doors: between terminals 10 and 12 in central locking unit 14-pin connector.
Rear doors: between terminals 3 and 4 in central locking unit 8-pin connector.
Trunk lid: between terminals 6 and 7 in central locking unit 8-pin connector.
Filler cover: between terminals 1 and 2 in central locking unit 2-pin connector.
The ohmmeter should indicate 1-15 Ohm in all cases.
If readings are correct:
Check operating switch signal leads as per C15.
If any reading is Incorrect:
Open circuit or short circuit in central locking unit wiring harness or in motor winding of unit giving incorrect reading. Correct the fault or replace motor. Reinstall central locking relay 2/7.
C15: Checking Operating Switch Signal Leads
Switch off ignition.
Lock trunk and all doors.
Connect an ohmmeter between relay base terminals 31 and 86.
The ohmmeter should indicate approx. 0 Ohm.
Connect the ohmmeter between relay base terminal 31 and each of terminals 85A, 85B and 85R.
The ohmmeter should Indicate Infinite resistance in all cases.
Unlock the trunk and all doors.
Connect the ohmmeter between relay base terminals 31 and 86.
The ohmmeter should indicate infinite resistance. Connect the ohmmeter between relay base terminals 31 and each of terminals 85A. 85B and 85R.
The ohmmeter should indicate approx. 0 Ohm in all cases.
If readings are correct:
Check interior lighting ground lead as per C21.
If readings for terminal 85A are incorrect:
Check left front door operating switch as per C16.
If readings for terminal 85B are incorrect:
Check right front door operating switch as per C16.
If readings for terminal 85R are Incorrect:
Check trunk operating switch as per C18.
C16: Checking Front Door Operating Switch
Switch off ignition.
Remove panel of front door with faulty central locking unit (fault tracing as per C15).
Open central locking unit 14-pin connector.
Lock the front door with the faulty central locking unit.
Connect ohmmeter between terminals 11 and 14 in central locking unit's 14-pin connector. Ohmmeter should indicate infinite resistance.
Connect ohmmeter between terminals 13 and 14 in central locking unit's 14-pin connector. Ohmmeter should indicate approx. 0 Ohm.
Unlock the front door with the faulty central locking unit.
Connect ohmmeter between terminals 11 and 14 in the central locking unit's 14-pin connector Ohmmeter should indicate approx. 0 Ohm.
Connect ohmmeter between terminals 13 and 14 in the central locking unit's 14-pin connector. Ohmmeter should indicate infinite resistance.
If readings are correct:
Check the ground lead of the front door operating switch as per C17.
If readings are Incorrect:
Fault in central locking unit's operating switch or wiring harness.
Correct the fault or replace the complete central locking unit. Reinstall the central locking relay 2/7.
C17: Checking Front Door Operating Switch Ground Lead
Switch off ignition.
Remove panel of front door with faulty central locking unit (fault tracing as per C15).
Open central locking unit 14-pin connector. Connect ohmmeter between terminal 14-pin wiring harness 14-pin connector and ground.
Ohmmeter should Indicate approx. 0 Ohm.
If reading is correct:
Check locking signal leads as per C20.
If redings are Incorrect:
Open-circuit or short circuit is present In ground lead between terminal 14 in wiring hamess 14-pin connector and ground terminal at A-post on drivers side 31/7 or passengers side 31/15.
Correct fault or replace operating switch ground lead. Reinstall central locking relay 2/7.
C18: Check Trunk Operating Switch
Switch off ignition.
Remove trunk lid panels as required.
Open central locking unit 8-pin connector.
Lock trunk
Connect ohmmeter between terminals 4 and 2 in central locking unit's 8-pin connector. Ohmmeter should indicate approx. 0 Ohm. Connect an ohmmeter between terminals 5 and 2 in the central locking unit's 8-pin connector. hmmeter should indicate infinite resistance.
Unlock trunk lid
Connect ohmmeter between terminals 4 and 2 in central locking unit's 8-pin connector. Ohmmeter should indicate infinite resistance. Connect an ohmmeter between terminals 5 and 2 in the central locking unit's 8-pin connector. Ohmmeter should indicate approx. 0 Ohm.
If reading are correct:
Check trunk operating switch ground lead as per C19.
If readings are Incorrect:
Operating switch is faulty. Correct fault or replace complete central locking unit. Reinstall central locking relay 2/7.
C19: Checking Trunk Operating Switch Ground Lead
Switch off Ignition.
Remove trunk lid panels as required.
Open central locking unit's 8-pin connector.
Connect ohmmeter between terminal 2 in wiring harness 8-pin connector and ground. Ohmmeter should indicate approx. 0 Ohm.
If reading is correct:
Check locking signal leads as per C20.
If reading is incorrect:
Open-circuit or short circuit to supply is present in ground lead between terminal 2 In 8-pin connector and ground terminal at left-hand side of luggage compartment 31/11.
Correct fault or replace operating switch ground lead. Reinstall central locking relay 2/7.
C20: Checking Locking Signal Leads
Switch off ignition.
Lock all doors and trunk.
Connect ohmmeter between relay base terminals 31 and 88.
Ohmmeter should indicate approx. 0 Ohm.
Unlock all doors and trunk
Connect ohmmeter between relay base terminals 31 and 86.
Ohmmeter should indicate infinite resistance.
If readings are correct:
Open-circuit or short circuit in unlocking signal lead between front door and trunk with faulty central locking unit and central locking relay (check as per C15). Correct fault or replace faulty signal lead as specified below:
Left front door: Signal lead between relay base terminal 85B and terminal 11 in wiring harness 14-pin connector.
Right front door: Signal lead between relay base terminal 85B and terminal 11 in wiring harness 14-pin connector.
Trunk: Signal lead between relay base terminal 85R and terminal 5 in wiring harness 8-pin connector. Re install central locking relay 2/7.
If readings are Incorrect:
Open-circuit or short-circuit in locking signal lead between front door and trunk with faulty central locking unit and central locking relay (check as per C15). Correct fault or replace faulty signal lead as specified below:
Left front door: Signal lead left side between terminal relay base 86 and terminal 13 in wiring harness 14-pin connector.
Right front door: Signal lead right side between relay base terminal 86 and terminal 13 in wiring harness 14-pin connector.
Trunk: Signal lead between relay base terminal 86 and terminal 4 in wiring harness 8-pin connector. Reinstall central locking relay 2/7.
C21: Checking Interior Lighting Ground Lead
Switch on Ignition.
Turn the courtesy light switch to the 0 setting.
Remove central locking relay 2/7.
Connect a voltmeter between terminals LA and 31 at relay base. Voltmeter should indicate approx. 0 V.
If reading is correct:
Replace the central locking relay.
If reading is Incorrect:
Short-circuit to supply in lead between relay base terminal LA and courtesy light 10/22:5.
Correct the fault or replace the lead and carry out a function check with central locking relay installed.
If the central lock does not work, the central locking relay must be replaced.