QuestionQuestion: My car: RR l322 S/C 4.2 november 2005 has the following problem
(which seems to be common, but on various forum I haven't found any
solution)
Randomly my car partially loses power steering and the back door + boot
locks will not open at all.
I have been studying some experts' advice, I have found that the partial loss
of power steering depends by a problem of communication between the BCM
and the solenoid on the power steering. Fair. That would suggest to replace
one or both of them. Nevertheless, the fact that, ALWAYS together with the
partial loss of power steering you cannot open back doors (only back) and
trunk..suggests that there is maybe some typical RR gremlin around.
any idea? have you already seen these symptoms?
thanks a lot wally
AnswerHi Wally,
I've seen both problems but always separately - not as a combined fault. I think your logic is correct and it seems to lead to the BeCM as the culprit. BeCM input and outputs include the security systems as well. Even the sunroof, AC, seats, centre console switches, doors are all monitored by the BeCM.
Here's something from the workshop manual that may be helpful:
<<
The BeCM also communicates with several outstations via a digital
serial data bus. The data bus allows the BeCM to ’talk’ to the
outstations by passing electrical information through the same
wires. Each data bus comprises five wires as follows:
• Feed wire Battery voltage supply
• Earth wire Vehicle earth
• Clock wire Reference signal
• Signal wire Transmits digital signals
• Direction wire Identifies direction of signal
>>
Outstations - doors, sunroof, ...
With older LRs, another common problem is corrosion and ground faults. Perhaps this may be an issue - especially with the doors.
I believe there are threads on the www.Discoweb.org site about BeCM faults.
I don't recall the BeCm ever failing outright but I won't discount that from ever happening.
BTW: If the BeCM is replaced, the system will have to be reset by the Testbook.
Best of luck,
JohnMc
