Calibrate the soft top?

[raysea390]

Im going to look at a 1992 300SL - the dealership says that the top does not work because it needs to be calibrated. What does this mean? Is it expensive or can I do it? Can the top be manually raised and lowered until I could fix it?

Also...do the early '90s SL's like this one have simpler electrics?

Thanks!

[deanyel]

Sounds like used car salesperson talk, sort of like the AC works great but it just needs freon. You need to ask them what they mean. Automated soft top repairs can be expensive, but the power top can be disabled and converted to manual operation. 90 to 93 300SLs are relatively simple DIY friendly cars compared to later cars.

[raysea390]

...so I doubt they would know anything about a soft top on an MB, but I will ask anyway. Thanks for your reply.

I see mention of troublesome wiring harnesses on 129's too...is a 92 300SL prone to this problem too?

[deanyel]

That being the case it's likely that the calibration story was just a guess. It's not unheard of that 3.0 liter 104 could have a wiring harness problem but it's not a congenital flaw on the car - that started on the 129 sixes with the HFM engine management system in 1994. The scary thing about the 90-93s is the EZL, aka ignition control module which is hard to find used and expensive new. The cost of a wiring harness pales by comparison.

[lynns]

Originally Posted by raysea390

Im going to look at a 1992 300SL - the dealership says that the top does not work because it needs to be calibrated. What does this mean? Is it expensive or can I do it? Can the top be manually raised and lowered until I could fix it?

The first thing to check on ANY R129 SL (1990-2002) is how the hardtop removes and how the soft top functions in the up and down mode. A MY92 could have any number of soft top hydraulic or controller problems. But if you are told that it needs to be calibrated that can mean any number of things. Expensive, yes if you take it to a Dealership and less expensive if you can find a good Independent that knows the soft top system in and out.

It is my suggestion that whatever you do please take the car to a well qualified Independent and pay him to check the car out. Remember there are a couple of things that are hard to check no matter what. Like the suspension. Will the car need an alignment? Are any of the rims bent? When was the last time the wheels were balanced? etc.

It is my suggestion that anytime you buy a used $90K car that you have at least $3K put aside in order to pay for any repairs that pop up or just to bring the car up to the way you want it.

[tecqboy]

The soft top controller in the 90 to 93 129 model is the simplest ( electronically speaking ) to reset. From time to time, small clitches in the electrical system of the vehicle will cause it to become confused, even though everything is working OK in the hydraulic system. ( This happens on my 91 300SL every now and then. ) The soft top and the roll bar controller can interact and affect the functioning of the system also. In any case, it's very easy to reset. Much has been written on this forum on how to build a simple home-made diagnostic tool for recoveing the error codes and reseting the controller. The car you are looking at is likely to be OK, but those unfamiliar with the reset procedure wouldn't have a clue as to how to go about fixing it.

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.

Tool BLACK = Pin 1 WHITE = Pin 10
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).

[cooltime2]

I have a 91 SL 300 with top trouble reading your codes and you list a 26 erra code but on list goes from 25 to 27 no 26 listed what is 26 code?

[tecqboy]

Code 26 is "Operation Time Exceeded". I don't know what that means in a literal sense. But that is what is listed in the scan manual. It is listed in the group that prevents the top from operating. My guess is that it means the top has failed to deploy or retract in a certain amount of time. If you are having a problem with the top, post your symptons.

[cooltime2]

I tried the reset process jumping out 1 and 10 didnt seem to get anything on resetting it getting same thing i have all working windows go down rollbar down compartment cover opens front locks release but no top function i hear a click on right side at back near cover lock i checked all my switches all seem to work when manually acuvated any ideas thanks.

[cooltime2]

also should the key be on or running to do reset at 1 and 10

[tecqboy]

Well, punctuation would help. How is the hydraulic fluid level? Is the hydraulic pump running while you hold the top switch or does is stop at some point with the switch still held? On my car, I need to have the engine running because the battery voltage isn't hign enough without help from the alternator to get enough pump pressure. Error 26 now seems approiate, given this description. You may need to remove the covers and have a look at the actuators and the plumbing. The seals go bad on the cyclinders after so many years, particularly if the top isn't used much.

[cooltime2]

i just did all the cylinders new seals full of fluid when i got the car 3 yrs ago the hydrolics leaked so didnt use them now trying get them working seems all working now except top not going down or up if i put it down. is that 2 pin plug going to roll bar a limit switch its reading closed with roll bar up or down and not reading any resistance on it so assume its a limit switch

[97 SL320]

try to test switch whit meter tste it switch not making comuter know it working follow sequence of op find where interupt could have hydro valve not work would haf to check that at hose pump needs to run at check