Defect Code 27
Defect Code 27:General malfunction :
(Troubleshooting with *D* test procedure):
General:
The *D* test procedure facilitates complete Inspection of all system components.
If the system is malfunctioning and there is no defect code stored in the defect code memory, specific and reliable troubleshooting is made possible by means of the *D* test procedure.
On all screen displays, check that the status indicated on the screen agrees with the actual status on the vehicle, e.g. vehicle is centrally locked - is "locked" displayed on the screen?
Further Information on troubleshooting can be called up on the display screen by pressing the ( down arrow ) key.
The test procedure is subdivided Into several test steps.
Test step 1: ZV Identification:
Test:
Lock and unlock the vehicle with the central locking system. The status detected by the control module is displayed on the screen. There is a defect in the system is the status displayed on the screen does not agree with the actual status on the vehicle.
Important!
If the vehicle cannot be locked or unlocked perfectly (all doors and the rear lid) then the central locking system is defective. In this case, check the central locking system - see ZKE central locking system.
Troubleshooting:
Symptom
The status of the central locking system at the doors is not displayed correctly.
Remedy:
Repair wire from control module connector B Pin 7 to ZV drive of driver's door (pin contact).
Symptom
The status of the central locking system and the rear lid is not indicated correctly.
Remedy:
Repair wire from control module connector B Pin 6 to ZV drive of rear lid (pin contact).
Test step 2: Test run:
Explanation:
The test run facilitates specific activation of the turn-catch lock drives. The relays In the relay module and the limit switch 53 are checked for defects during the test run. During the test run, the turn-catch drive turns twice thus moving In the "close" and "open" end positions. By entering a number on the selection page, the turn-catch drive, for which the test run is to be performed, is selected.
Caution!
Danger of Injury!
Reaching into the turn-catch as it turns causes serious injuries!
No protection facilities are active during the test run!
Take particular care to ensure that no objects fall Into the turn-catch!
Before performing the test run, the vehicle door must be opened completely otherwise the turn-catch will damage the closing pin.
Notes:
The test run cannot be carried out when one of the following conditions exists:
Condition:
Limit switch (S3) stored as defective In defect code memory (defect codes 15 - 19).
Remedy:
Clear defect code memory. The system checks the limit switch during the test run.
Condition:
A relay defect is stored in the defect code memory (defect codes 01 - 14).
Remedy:
Rectify defect In accordance with instructions. Then clear defect code memory.
Test:
Open vehicle door! Start test run with 300 and acknowledgment key. Observe the turn-catch during the test run and check that the turn-catch actually turns.
On completion of the test run, whether the turn-catch was turned or not is entered at the tester. After this entry, the diagnostic program automatically checks whether the control module had detected a defect and Indicates this defect if necessary.
Important!
Due to the mechanics of the lock it is possible that the turn-catch does not snap back automatically to the "open" position when the vehicle door is open although the turn-catch drive returns to this position! This is not a fault!
In these cases, the turn-catch must be carefully pressed back to the "open" position with a tool while completely lifting the door handle.
Troubleshooting:
Test step 3: Switches:
The turn-catch drive, whose switches are to be checked, is selected by entering a number on the selection page.
Test:
Door handle switch (S1):
Slightly raise inside or outside door handle. "ON" should appear on the display screen when the door handle is raised.
Initial-detent switch (S4):
Close vehicle door and then open again. The turn-catch must now be completely open. "OPEN" should be displayed on the screen.
Then close the vehicle door so that the turn-catch engages In the first detent position (Initial-detent position). "NOT OPEN" should be displayed on the screen.
turn-catch switch (82):
Close vehicle door and then open again. The turn-catch must now be completely open. "OFF" should be displayed on the screen. Then close the vehicle door and lightly press on reaching the first detent position. "ON" should be displayed on the screen.
Effect of defect:
Switch failure:
Door handle switch:
After opening the vehicle door, the turn-catch drive does not move to the "OPEN" end position. Electrical closing is then no longer possible.
Initial-detent switch:
The position "door completely open" is not detected. After opening, electrical closing is not possible before the vehicle door was completely opened. Electrical closing is therefore no longer carried out.
Turn-catch switch:
The SCA function detects no "close turn-catch" signals.
Troubleshooting:
Applicable to all switches In the case of defect:
- Is fuse OK.?
- Is wire from fuse to microswitch OK.?
- Is microswitch mechanically OK.? (terminals, mounting, etc.)
- Is microswitch electrically OK.? (Continuity, short-circuit)
- Is plug connection at microswitch OK.?
- Is wire from microswitch to control module OK.?
End:
The system is electrically OK. If no defects are found during the test procedure.