Thread: Door unlocking question

Originally Posted by Alan M

If it does turn out to be the BCU, is the fix simply a matter of switch the old unit for a new one, or is there more to it - eg reprogramming it and, if so, is that difficult? I'm still new to this vehicle and still getting my head around a lot of stuff.

A replacement BCU needs serious programming by someone who knows what he's doing

A replacement BCU needs serious programming by someone who knows what he's doing



Point taken. I won't rush into it unless really needed.


Would appreciate some feedback on whether, in my case, the risk of lockout is high (and I need to something soon) or low/lowish (in which case I can proceed as is and just monitor things). In particular, would like feedback on whether door lock/unlock failures are more commonly switch or actuator failures (see my train of thought below).


Update: Sierrafery's prognosis seems to be right - ie the BCU is going to sleep too quickly. The other suggestion of the battery being low doesn't seem to be the culprit because I connected a trickle charger overnight and the handset failed this morning.


From what I can work out, the BCU normally gets and responds to lock/unlock signals/currents from two sources:

1. a receiver in the roof that responds to the remote, and
2. a switch in the driver's door.

In my case (once parked overnight), it's just one source - driver's door. Thus I'm totally reliant on the door switch working. By the same token, as long as the driver's door switch is working such that, on turning the key, a current is sent to the BCU and the BCU wakes up, I should be okay and not be locked out. That is, I should be okay even if the driver's door actuator fails (provided the switch works).


Assuming the above is broadly correct, I'm interested in feedback on whether door locking/unlocking problems are commonly driver's door switch problems or actuator problems. (There seems to be a number of posts on actuator failures but haven't read them in detail to see how many involve switch failures.) My thinking is that if there are a lot of switch-related problems then I need to be careful, but if most are actuator problems (and switches are pretty reliable), then I can be a bit more relaxed.


Any feedback much appreciated.


ps - how do you put a quote from a previous post in a text box? Looks good but haven't figured out how to do it.

Originally Posted by Alan M

... I'm interested in feedback on whether door locking/unlocking problems are commonly driver's door switch problems or actuator problems....

The switch is part of the actuator