129 500SL Roof problem

[bryn_p]

Hi all,

I have a 1989 R129 500SL which has been stood for over 2 years. When I tried to operate the roof from the down position a few weeks ago (after removing the hard top), hydraulic fluid started pouring out of the windscreen pillar. I replaced the leaking cylinder but the roof will still not go up. When I checked the pump, the fluid was right down to the bottom of the container so I filled it back up with fluid from MB but still the roof will not raise.

I can see the roll bar moving very slightly (couple of mm) when the switch is activated, but no part of the roof actually moves.

Do I need to get something reset, or look elsewhere for a problem, bleed the hydraulic system or just take it to a dealer to get the codes read?

I have another 129 SL to remove parts from if there are some likely culprits to check out.

Many thanks in advance,
Bryn.

[bobterry99]

There is no need to bleed the hydraulic system. I would read and erase diagnostic codes. On cars made before 1994, you simply need a paper clip or wire.

To read a code, you short socket #10 of the diagnostic connector to socket #1 for 2 to 4 seconds. After a moment the light in the convertible top control switch will flash. The number of flashes is a code. To get the next code, short the sockets again for 2 to 4 seconds. To erase a code, first read it and then short the sockets for 6 to 8 seconds.

If you need more detailed help with the procedure, you can send me an email.

[tecqboy]

Mercedes Soft Top Controller Reset Procedure. R129 1989 thru 1994.

Locate the diagnostic connector: Under the black plastic cover near the hood-up switch on
the US passenger side of vehicle near the strut mount.

To recover codes from the soft top controller:

Connect a normally open (N.O. S.P.) switch between pin 1 and pin 10. A simple push button switch with leads or a short jumper lead will also work OK.

Short (close switch) 2 to 4 seconds to read error codes.
The lamp in red (operate) top switch ( in the console ) will flash out a number of pulses.
Count the pulses and see the chart.

Short (close switch) 6 to 8 seconds to erase error code.

There may be multiple codes stored, so read / erase until all are cleared or the problem
Is located.

Some codes may require reading / resetting twice before they will erase.

The codes that will suspend operation of a soft top on the R129 are 21, 22, 26, and 30.

A code of "1" indicates no faults and no hard top in place, while a code of "20" indicates no faults and the hard top is assumed to be on the car.

3.= Limit switch, right locked ,soft top storage compartment cover.
4 = left compartment cover closed switch
5 = right compartment cover closed switch
6.= left front latch switch.

10.= left rear latch switch.
11.= right front latch switch.

16 = roll bar retracted switch.
17 = Left window failed to lower (limit switch open).
18.= Right window failed to lower (limit switch open).

20 = Hard top installed, no faults.

23 = roll bar control unit not functioning.

25.= contradicting inputs.

27 = insufficient voltage.
28.= Speedometer signal is missing.
29.= Wheel speed from ABS control module missing.
30 = Top operation disabled (due to #29).

[bryn_p]

Great, thanks for your help guys. I'll give that a try tomorrow.

One more question though - what position should the ignition be in for the above procedures?

Many thanks,
Bryn.

[bryn_p]

Hello again!

I've tried the above procedure with the iginition on and got about 50 error codes! After erasing them all, I keep getting code 20, ie. the hardtop is on with no faults.

Thing is, the hard top is not on the car! If I reset this code and try the roof again I keep getting code 20 back.

Any ideas how to solve it? Should I try actually putting the hardtop back on?

Thanks again,
Bryn.

[bobterry99]

I believe the latches for the top are out of position. This would be the two in the windshield and the two at the rear. If you operate the system to remove the phantom hardtop, then the latches might return to their correct (open) position. If this doesn't work, then you will have to do it manually with the special tool that came with the car tool kit.

[lynns]

Originally Posted by bryn_p

I replaced the leaking cylinder but the roof will still not go up. When I checked the pump, the fluid was right down to the bottom of the container so I filled it back up with fluid from MB but still the roof will not raise.

I can see the roll bar moving very slightly (couple of mm) when the switch is activated, but no part of the roof actually moves.

Bryn.

Bryn,
You mentioned that after you fixed the leaking cylinder that the fluid was at the bottom of the container and that you filled the reservoir. The reservoir only holds about 250 ml when it is filled to the min/max mark and the entire system holds 1.25 liters. In order for the system to work properly you may have to cycle the system more than several times in order to refill it completely. Please read Hydraulic system fluid flush and renew

[bryn_p]

Hi again all,

I have now replaced both cylinders in the windscreen surround and got rid of the 20 hard top in place code, but I am now getting error codes 2 and 3.

2 is not listed - any ideas what this is?

And what do I need to dismantle to investigate code 3?

Really appreciate your help on this everyone

Many thanks again,
Bryn.

[tecqboy]

I really need to update that list of error codes and re-post it. Code 2 is: Limit switch LEFT locked, soft top storage compartment cover. That would fit right along with your error code 3: Limit switch RIGHT locked, soft top storage compartment. You will need to use the special "tool" which is in the owner's tool kit to manually operate the top. There are instuctions in the owners manual I believe.

[bryn_p]

Originally Posted by tecqboy

I really need to update that list of error codes and re-post it. Code 2 is: Limit switch LEFT locked, soft top storage compartment cover. That would fit right along with your error code 3: Limit switch RIGHT locked, soft top storage compartment. You will need to use the special "tool" which is in the owner's tool kit to manually operate the top. There are instuctions in the owners manual I believe.

Great, thanks for the info.

So will manually operating the top fix the problem or is something broken?

Thanks again,
Bryn.

[bobterry99]

Those codes mean the top controller is not getting feedback that the soft top compartment cover is closed and locked at both the left and right-side latches. You may need to use the manual tool that tecqboy mentioned to figure-out if they are actually not locked. If they aren't locked, you may have an hydraulic problem. If they are locked, then you have to troubleshoot the limit switches that are on the latches, as they may need adjustement or replacement.

[lynns]

Originally Posted by lynns

Bryn,
You mentioned that after you fixed the leaking cylinder that the fluid was at the bottom of the container and that you filled the reservoir. The reservoir only holds about 250 ml when it is filled to the min/max mark and the entire system holds 1.25 liters. In order for the system to work properly you may have to cycle the system more than several times in order to refill it completely. Please read Hydraulic system fluid flush and renew

bryn_p, did you do the above? Have you checked the reservoir to make sure that it is at the min/max?

Please look at the rear latches and see if they are both in the same position. If not get the manual tool out and follow the owners manual instructions for raising the top. It will take two people to manualy raise it out of the compartment and rest it on the front windstop/windshield piller. Lift the back part of the top and close the compartment. With the ignition switch at the #2 position, windows down, doors shut, have someone push the red switch forward while you gently push the right side into the rear latch.

If you can get it to work cycle the top several times and make sure that the reservoir is at the min/max.

Please let us know what fixed your problem!

[bryn_p]

Well for those that are interested, the saga continues!

After much cursing I manually got the soft top up and locked down correctly. Now when I operate the switch to put the roof down, the rear of the soft top lifts but the cover for the storage compartment does not raise and I get fault code 2.

Can anyone suggest if this is a hardware failure and what is the best way to go about repairing it? Is it a dealer job at this stage?

Many thanks again,
Bryn.

[tecqboy]

Well, FWIW I'm interested. I had a love / hate relationship with my top also. I'd check the actual limit switch with an ohm meter to see if it faulty. I was once head of maintenace on some fancy robotic systems and those damn micro switches failed frequently. They can get just a bit out of position too. Look at the switch arm actuator. When I first got my car, the top system was full of electrical bugs, but eventually I tracked them all down and the top has been working perfect now for 3 years. Here again is the newest improved list of codes.


Roll Bar Codes and Reset Procedure.

Locate the diagnostic connector: Under the plastic cover over the hood-up switch on
the passenger side of vehicle near the strut mount.

Connect LED + to pin 16 (+12V) Connect LED – to ground ( Pin 1 ). Use an LED with resistor.

To read error code: Use a push button switch to short pin 7 to ground (Pin 1) 2 to 4 Seconds.

To Erase: Close switch 6 to 8 seconds.

Code 1 = No faults in system.
Code 2 = Roll Bar Control Unit
Code 3 = Voltage Supply
Code 4 = Driver Seat Belt Lock Relay (K18/2) open or short circuit to terminal 30 and/or 31
Code 5 = Passenger Seat Belt Lock Relay (K18/3) open or short circuit to terminal 30 and/or 31
Code 6 = Roll Bar Deployment Solenoid (Y57/1) open or short circuit to terminal 30 and/or 31
Code 7 = Left and/or right rear axle switch open or short circuit to terminal 30 and/or 31
Code 8 = Roll Bar Warning Lamp
Code 9 = Roll Bar Warning Lamp and/or impulse counter held too long to erase malfunctions
Code 10 = SRS Control Unit



Mercedes Soft Top Controller Reset Procedure. R129 1990 thru 12/93.

Locate the diagnostic connector: Under the black plastic cover over the hood-up switch on
the US passenger side of vehicle near the strut mount.

To recover codes from the soft top controller:

Connect a normally open (N.O. S.P.) switch between pin 1 and pin 10. A simple push button switch with leads or a short jumper lead will also work OK.

Short (close switch) 2 to 4 seconds to read error codes.
The lamp in red (operate) top switch ( in the console ) will flash out a number of pulses.
Count the pulses and see the chart.

Short (close switch) 6 to 8 seconds to erase error code.

There may be multiple codes stored, so read / erase until all are cleared or the problem
Is located.

Some codes may require reading / resetting twice before they will erase.

The codes that will suspend operation of a soft top on the R129 are 21, 22, 26, and 30.

A code of "1" indicates no faults and no hard top in place, while a code of "20" indicates no faults and the hard top is assumed to be on the car.

2 = Limit switch, LEFT locked, soft top storage compartment cover.
3 = Limit switch, RIGHT locked, soft top storage compartment cover.
4 = Limit switch LEFT closed, soft top storage compartment.
5 = Limit switch RIGHT closed, soft top storage compartment cover.

6 = Limit switch LEFT locked, soft top fabric bow.
7 = Limit switch RIGHT locked, soft top fabric bow.
8 = Limit switch LEFT closed, soft top fabric bow.
9 = Limit switch RIGHT closed, soft top fabric bow.

10 = Limit switch LEFT front locked, soft top.
11 = Limit switch RIGHT front locked, soft top.

12 = Limit switch soft top storage compartment open.
13 = Limit switch soft top fabric bow raised.
14 = Limit switch soft top down in storage compartment.
15 = Limit switch soft top up ( secondary closing speed ).

16 = roll bar retracted switch.
17 = Left window failed to lower (limit switch open), bad fuse, or window relay on controller.
18 = Right window failed to lower (limit switch open), bad fuse, or window relay on controller

19 = Vehicle speed signal to controller missing or illogical.

20 = Hard top installed, no faults.

21 = Controller module / soft top switch circuit open.

22 = Roll bar switch activated.
23 = roll bar control unit not functioning.
24 = Roll bar crash deployed.

25 = contradicting switch inputs.

27 = insufficient voltage.
28 = Speedometer signal is missing.
29 = Wheel speed from ABS control module missing.
30 = Top operation disabled (due to #29).

[bobterry99]

Originally Posted by bryn_p

Now when I operate the switch to put the roof down, the rear of the soft top lifts but the cover for the storage compartment does not raise and I get fault code 2.

You cleared all stored codes and code 2 came back, right?

Code 2 means that the top controller is not getting feedback that the left soft top compartment cover latch is unlocked. If the latch failed to unlock, then you may have an hydraulic problem. If it is unlocked, then you have to troubleshoot the limit switches that are on the latch, as they may need adjustement or replacement.