R 129 Retracting Roof ECU Re-set
Discussion
Basically, I jump started my R129 using a Noco Power pack. Battery was not dead, but though it turned the engine there was insufficient voltage to fire up my 5 litre V8.
Prior, to this, the hard top was off & the retracting roof worked fine.
The Noco fired up the engine, but on replacing the battery. The roof did not fully retract - in that though the rear part unfolded & the rear compartment which stores the fully retracted roof opened electronically, the front part of the roof that slots into the front window frame refused to budge.
Mercifully, the roof was able to close back & the rear compartment closed, meaning I could drive the car over the winter.
Upon doing my research, much of it pointed to the roof ECU being damaged.
Anyway, my favoured mechanic suggested that I :
1. Wind down the electronic windows
2. Disconnect the negative battery terminal/ switching the parking lights on (to completely drain any electricity from the car).
3. Wait (I waited 24 hours) - re-connect the negative terminal & re-set the electric windows & then try the retracting roof & it sorted out the problem, as the roof cycle is working normally in time for the Spring/Summer!
Prior, to this, the hard top was off & the retracting roof worked fine.
The Noco fired up the engine, but on replacing the battery. The roof did not fully retract - in that though the rear part unfolded & the rear compartment which stores the fully retracted roof opened electronically, the front part of the roof that slots into the front window frame refused to budge.
Mercifully, the roof was able to close back & the rear compartment closed, meaning I could drive the car over the winter.
Upon doing my research, much of it pointed to the roof ECU being damaged.
Anyway, my favoured mechanic suggested that I :
1. Wind down the electronic windows
2. Disconnect the negative battery terminal/ switching the parking lights on (to completely drain any electricity from the car).
3. Wait (I waited 24 hours) - re-connect the negative terminal & re-set the electric windows & then try the retracting roof & it sorted out the problem, as the roof cycle is working normally in time for the Spring/Summer!
Edited by axj on Thursday 13th March 10:42
Edited by axj on Thursday 13th March 10:46
I have had all sorts of fun with this mechanism over the years. I have even replaced entire the entire mechanism.
There are a few points of failure, the box is quite common, followed by the pin switches.
The box lives under the rear seats.
If you can swap in another good box you will be able to eliminate yours from your investigations, or prove yours is bad.
There is a man in Kent who fixes them for about £300. called Inga.
His email address is electronicsservices28@gmail.com
You could send him an email and find out if he is still doing it.
There are a few points of failure, the box is quite common, followed by the pin switches.
The box lives under the rear seats.
If you can swap in another good box you will be able to eliminate yours from your investigations, or prove yours is bad.
There is a man in Kent who fixes them for about £300. called Inga.
His email address is electronicsservices28@gmail.com
You could send him an email and find out if he is still doing it.
I’ve had similar issues when my 97 SL500 had a low battery. The problem was caused by the error codes the low battery situation had caused when I operated the roof. Clearing the codes (using a code reader - disconnecting the battery did not work in my case) saw the problems disappear and 8 years later all is still fine.
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