Keyless Entry - Doors Won't Unlock When Using Remote
SI B51 19 07Body Equipment
August 2011
Technical Service
This Service Information bulletin supersedes SI B51 19 07 dated September 2009.
[NEW] designates changes to this revision.
SUBJECT
Doors Will Not Unlock Using the Key Fob or Central Locking Button
MODEL
E90, E91 (3 Series) produced up to 11/2008
SITUATION
One or more of the doors may not unlock when using the remote key outside the vehicle, or the central locking button inside the car. It is still possible, however, to unlock the door by using the key in the driver's door lock cylinder or by pulling the door handle on the inside of the car.
Typically fault codes A6D4 and A6D5 are stored in the Junction Box Electronics (JBE).
CAUSE
This is due to a blown fuse in the JBF caused by either:
^ An excessive amperage draw by one of the door lock actuators, which is commonly attributed to silicone contamination; or
^ An intermittent, but acceptable, amperage spike slightly above 15A, due to normal variation in the locking system.
CORRECTION
Replace the fuse with one of a different rating.
Replace the necessary actuator as well, but only if it is drawing excessive amperage.
NOTE:
Never spray any silicone products into the latch, as this will lead to premature failure.
PROCEDURE
1. Perform a vehicle test using ISTA.
2. Inspect fuse 57 (up to 9/07 production) or 73 (from 9/07 production) in the JBE.
3. Replace the blown 15A fuse with a 20A fuse.
4. Perform a function test by activating the door locks 10 times in succession via the central locking switch.
NOTE:
The thermal protection will be activated after about 15 successive activations and does not indicate any damage to the system.
5. Carefully observe the operation of each lock actuator while it is being cycled. Lock actuators with some degree of damage will exhibit noticeable symptoms of this, such as slow operation, abnormal noise, etc.
^ If either one of the front door lock actuators is determined to be the source of the blown fuse, both front door latches (which contain the lock actuators) should be replaced per Repair Instruction REP 51 21 090. For this replacement, the door latch kit, which contains both the left and right side latches, must be used.
^ If either one of the rear door lock actuators is determined to be the source of the blown fuse, only that single faulty latch should be replaced per Repair Instruction REP 51 22 090.
^ If one of the front lock actuators and one of the rear lock actuators appears to be faulty, both front latches and the single faulty rear latch should be replaced per Repair Instruction REP 51 21 090 and REP 51 22 90.
^ If no faulty lock actuators can be identified, wait 2 minutes and then repeat step 4.
NOTE:
If any door latches are to be replaced, the attached procedure should be utilized in conjunction with the REP noted above. This attachment will reduce the amount of time necessary to perform the replacement.
6. After the second functional test, if no faulty lock actuators can be identified, none of the latches should be replaced.
PARTS INFORMATION
[NEW] WARRANTY INFORMATION
ATTACHMENTS
B511907 Procedure/Labor Information