psuedombtech

I am working on a 2001 clk430 and the soft top will go down with no problem but it stops on the way up/closing after it lifts fully out of the trunk. The pump continues to run but the fabric bow does not lift up to then let the compartment lid close. I have an sds and all of the switch status' seem to read as they should given the position of each component in the system. There are no faults stored, there are no fluid leaks and the reservoir is full. The release screw is turned fully clockwise/closed and the rollbars are fully retracted as they should be to allow top operation. I can see using the sds that the module is not activating the solenoid which is supposed to lift the fabric bow up (the next step in the closing sequence). The status of the soft top open/close switch (s84/13s1 and s2) seems accurate-i.e. switch reads open when top is in trunk then reads "clamped" when coming out of the trunk in the intermediate position then reads closed when the top comes fully out of the trunk and stops as it should near the front window cowl. The next step is for the bow to go up-it just doesn't happen. If I close the top manually then try to open it the fabric bow lifts up and the top opens fully into the trunk, the compartment lid comes down and locks, the window go up and all is good.

psuedombtech

I found that the limit switch for the soft top position was reading "in catch position" when it was near the windshield before locking it in with the handle. The three position switch (S 84/13 s1/s2) should have been reading "closed" when in this position so that the rear bow/window part of the top could swing up to let the compartment lid down. I replaced the switch and now the top works fine. You really need a fully compatible scan tool like an sds or autologic to tell you what the computer is seeing/thinking. When dealing with soft top issues it really helps to think about the symptoms and in which position the top is in when it's stuck to solve the root of the problem.

GatorMB

Thanks for the heads(top) up. Do you you have a link for the tool you are using to summize the top functions/

Nice fix,
Cheers, Gator

psuedombtech

I am an automotive technician at a European independent in California but I have found that sometimes I get as much useful information from these forums as I do from the professional resources that our shop pays for (that's why I posted here hoping to get some help). Some of you MB owners know more about your cars than I do and I do it for a living. We work on so many different brands that we don't get to know any one line all that well. The diagnostic scanners I was referring to are the SDS which is "THE" dealer level diagnostic tool used at all MB dealers- aftermarket versions of it can also be purchased online as software loaded onto a laptop (just google "Mercedes + sds (or xentry). The "Autologic" I referred to is another diagnostic tool used by many independent repair shops but is also very expensive. Another option would have been to simply backprobe the connector at the soft top control unit. I believe pins 31 and 33 are the two inputs for the soft top microswitch that is mounted near the hydraulic ram on the left side for the soft top main pillar. When the top is open fully in the trunk, the/ "open" microswitch sends the computers voltage to ground and so the computer sees the voltage on that pin go to zero. When the top comes out of the trunk and is still in the intermediate halfway position, neither the open or closed switch is activated so both pins 31 and 33 have whatever voltage (12 or 5 volts) the computer is putting out because it cant go to ground through the microswitch. Then when the top comes as far forward as it can without crashing into the front windshield/cowl, the soft top position is recognized as closed as pin 33 voltage can now go to ground through the microswitch. It is at this point that the computer will activate the fabric bow/rear window hydraulics and lift the bow so that the compartment cover can come down. When a convertible top stops without getting to the next position its often because it doesn't like the status of a microswitch and all of the switches can be checked at the computer connector by backprobing that particular pin-you need the correct wiring diagram or the correct pin assignments to tell you which pin to check. Let me know if you have any more questions or comments and thanks for responding as soft top issues are not ones that people care to talk about but the top operation really isn't that complicated eventhough there are a lot of components involved.

GatorMB

I too am a retired ASE Master and worked a Euro Indy Shop. I Interned with VW in the day. Now in Industrial Control systems. My Inquiry was for interest to enthusiast inquiring easy repairs.
A breakout box was required back some time ago to access the top controller on this car. STAR is known for diagnostics and Xentry repair. SDS is new for me but I have been out of the loop other than CAN protocol development.
Thanks for the explanation. Most repairs are hopefully helpful to shade tree DIY in the forum.
Regards, Gator

Serndipity

psuedombtech.........first, congratulations on a successful repair, which involved excellent troubleshooting skills. Specifically, the way the MB STAR diagnostic generates body trouble codes, is based on whether or not the controller receives an input or output completion acknowledgement within a defined time-frame. This only isolates, or points, to an area to explored further, which involves additional/substantial troubleshooting skills, to determine if the issue is with a controller faulty input/output.

Next, I couldn't agree more, with your above opening sentence, that the forum has previously posted a treasure chest of information. Specifically, numerous times, I posted a functional diagram of the power roof controller, but more importantly, also detailing the inputs/outputs required at every stage of roof operation etc., which is the key to successful troubleshooting and repair (e.g. the controller connector pin-out, how to test/troubleshoot at every stage of power roof operation etc. .

Note: All of the controller inputs (except those from the CANBus) can all be verified, by disconnecting the controller connection and takings resistance measurements with a multimeter. Only checking the controller outputs, requires the MB break out box, mentioned by GatorMB, which would point to a faulty controller/pump solenoid valve etc.

All this said, I am still an original owner of 2001 cabriolet, while yet, no problems with my power roof operation, which I have a theory as to why.

That said, the W208 has proven to be one of the most reliable MB vehicles has recently produced. However, the cabriolet design is a looker/keeper and will wind up in your shop, for time forward.

Important, MB did some significant upgrades to the power roof system, on or about 2001. Specifically,in later production, the pump assembly, only uses 5 solenoid valves (e.g. vs. 7), some of the position position/limit switches were eliminated (e.g. involving the soft top cover), which then involves very different controller and programming. Note: From what I can see from the updated WIS electrical schematics, the connections at the controller, still remain the same (e.g. just the controller software programing has changed).