Hi all,

I have the following error code showing on my R230 SL which I think happened after accidentally shorting the vario roof pump connectors while cleaning them:

SL R230 RVC Hydraulic Pump Fault A7/5b1 Temperature Sensor

Has anyone else had this problem and has anyone ever tried to replace the temperature sensor or managed to fix the issue?

Many thanks
Robot

2006 S.L. 350 R230

 

I would measure the voltage being supplied by the ABC controller to the sensor. To measure you separate the connector from the sensor and connect your meter to sockets #1 and #3. If the identity of those sockets is somehow unclear to you, then make all three possible measurements among the sockets.

If you measure 5.00 volts DC +/- .25 volts, then the supply is good and the sensor is suspect. Otherwise, the controller is suspect.

 

Hi Bob, thank you very much for your detailed reply.
My apologies, I should have stated the error is coming from the vario roof hydraulic pump.

 

That is ungood.

A temperature sensor is integrated into the motor. I do not know if it is serviceable. I have a good, spare motor somewhere around my house that I would happily part with. PM me if interested.

You can check the sensor by removing one of the electrical connectors to the roof controller and measuring resistance. Since I think the controller is difficult to access, you may not wish to bother. But if you do, I can provide testing information.

 

Hi guys, I don't want to be one of those people who come to sites for help and never posts a response or update on an issue, so here goes:

Firstly, thank you for very detailed responses from the technical experts here!

The error code I had appeared to be linked to the roof hydraulic motor electrics (follwing some great wiring diagrams on this site) and it appeared to be inside the hydraulic motor itself. So I tried replacing the hydraulic motor for one with a warranty from an excellent company up north that also gave me a discount for returning my old motor - Roofmotors UK. I highly recommend this company. Their service is excellent!!!

After simply replacing the motor (just 2 bolts), the error still existed and could not be cleared. Yes a waste of £200 but still cheaper than taking it to Mercedes.

I finally stopped trying to decode the error myself and took the car to Cayman Autos in Surrey. They are specialists in convertibles of all makes.

They installed one of their own pneumatic motors and the roof worked perfectly and the error codes did not return when cleared!

I did not want to pay the £1200 for a new pump and installation knowing that I could replace this myself if I could find a cheap one. Cayman only charged about £80 for the diagnosis.

I found a fantastic seller named David Arnott on eBay. David posts advice on here and is the nicest expert I've come across!!! I bought a fully refurbished pneumatic pump from David and this came with a 12 month warranty and a full diagnostic/programming report.

I installed the new pneumatic pump and now not only does the roof work perfectly but the error codes have cleared and all the features that were not working previously are now working!!! Such as the central locking of the passenger door from the inside (external key central locking did work) and the boot soft close and rear shelf lift now also work as well!!!

So once again it looks like several unrelated problems were all down to one faulty component, namely the pneumatic pump.

Thank you all and I hope this post will help someone else.

P.S. I also had a faulty boot shelf partition sensor that I replaced with a used sensor !!!!