B1452
Symptom: The fifth bow cannot be operated.
#5 Bow Motors. Short Circuit / Short to Ground / Stall Current
Fault symptoms
The fifth bow cannot be operated.
Conditions
Open circuit or short to ground on pin 13 (K20) or pin 14 (K20).
Warning
|
|
The normal control module safety functions are disconnected when the soft top mechanism is operated with the diagnostic tool. The motors continue to run as long as the diagnostic tool activates them, irrespective of the position of the soft top, fifth bow or soft top cover. Use caution and always lower the rear seat backrest.
|
|
|
|
|
|
Diagnostic help
The fifth bow motors can be activated and its status read with the diagnostic tool.
|
-
|
Connect the diagnostic tool.
|
|
-
|
Turn the ignition switch to the ON position.
|
|
-
|
Read the status of the motors or activate it.
The status of the motors can be:
|
Make sure the fifth bow is moving freely by activating the motor with the ROOF button or diagnostic tool. Alternatively, disengage the motor with the emergency closing lever and pull the fifth bow up and down by hand.
The direction of rotation of the motor is changed by reversing the polarity.
|
•
|
The motor goes up when pin 13 (K20) is +.
|
|
•
|
The motor goes down when pin 14 (K20) is +.
|
Checking the wiring
Intermittent faults can occur during temporary short circuits and open circuits. Jiggle the wiring harness in several places and in various directions to detect problems in the wiring harness and connectors. Watch the multimeter, diagnostic tool and test lamp during the check.
Diagnostic procedure
1. Check the power supply to the motors
|
-
|
Connect the diagnostic tool.
|
|
-
|
Turn the ignition switch to the ON position.
|
|
-
|
Connect the test lamp and activate as follows:
|
|
|
•
|
On the right-hand motor:
between pin 1 and ground, activate UP
between pin 2 and ground, activate DOWN
The test lamp should light up.
|
|
|
•
|
On the left-hand motor:
between pin 1 and ground, activate DOWN
between pin 2 and ground, activate UP
The test lamp should light up.
|
Does the test lamp light up?
Continue with step 2.
Check and, if necessary, rectify the relevant lead. Continue with step 3.
2. Check the mechanical function of the fifth bow
|
-
|
Disengage the fifth bow motor by activating the emergency closing lever.
|
|
-
|
Operate the fifth bow by hand. Make sure it runs smoothly without getting jammed.
|
Is the fifth bow running freely?
Continue with step 3.
Rectify the fault. Continue with step 3.
3. Localize the faulty motor
|
-
|
Connect the diagnostic tool.
|
|
-
|
Reset the emergency closing function.
|
|
-
|
Turn the ignition switch to the ON position.
|
|
-
|
Activate the motor with the diagnostic tool.
|
|
-
|
If everything is correct the fifth bow should move.
|
Is the function correct?
Repeat the procedure with both motors connected. If the fifth bow works when both motors are connected, check and if necessary rectify the motors, emergency closing lever switch and lead. Continue with step 4.
Change the motor and continue with step 4.
4. Final check
|
-
|
Clear the diagnostic trouble codes.
|
|
-
|
Activate the soft top with the ROOF button and operate it for a few cycles
|
|
-
|
Make sure the soft top is functioning correctly and that no diagnostic trouble codes are generated.
|
Has the diagnostic trouble code recurred?
Change the control module as described in
The fault has been rectified.
