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a_florida_man Reader
12/4/18 10:01 p.m.

We will see what tomorrow brings, but as it stands now, I just bought a 1998 SLK230 for  $1000, and I'm happy about it.

Hard to say if that will stand... I paid a deposit for it tonight to jump in line of all of the other folks who would normally do these things during the day. That sounds legit, right?

Sooo after I pick it up tomorrow night, I'll post the first "Pre-Mortem" analysis.


Known good:

It runs, drives, has AC and generally is all there.

Had the transmission rebuilt 2 years ago.

No significant body damage.


Known bad:

It likes to invoke "Limp Mode".


Right Now I'll leave you with all of the grandeur of the Facebook market place ad and pics:

jfryjfry HalfDork
12/4/18 10:09 p.m.

I think you’ve already done too much investigative work into this vehicle.  Looking forward to the autocross results this weekend!

Robbie UltimaDork
12/4/18 10:27 p.m.


a_florida_man Reader
12/4/18 10:29 p.m.

In reply to Robbie :

It's no MR2... but it is supercharged.. lol.

John Welsh
John Welsh Mod Squad
12/5/18 12:30 a.m.

So close to being a Chrysler Crossfire devil

a_florida_man Reader
12/5/18 5:46 a.m.

In reply to John Welsh :

I like to think of it as an uppity Miata...:)

¯\_(ツ)_/¯ UberDork
12/5/18 6:08 a.m.

The only person I know with a Kompressor'd Mercedes spends roughly 2 challenge budgets per year to keep it on the road.  I'm confident you can do better.

Gunchsta HalfDork
12/5/18 9:16 a.m.

You GRM people are brave souls. An aging Mercedes that likes to go in limp mode screams "run far away!!" to me, but I'm excited to be proven wrong. 

Pete Gossett
Pete Gossett MegaDork
12/5/18 11:07 a.m.

In reply to a_florida_man :

If you really want a challenge, swap this drivetrain into your C4. 

Vigo UltimaDork
12/5/18 12:36 p.m.

I drove a really nice one of these with the rare manual trans. It just didn't work for me. I actually think the main thing that holds them back is the 'character' of the engine. Its powerband, noise, etc. But, i'm pretty sure at a cheap enough price I'd be willing to look into fixing that, so maybe this project is going to turn out better than my little fishing expedition. Looking forward to hearing more!

Cotton PowerDork
12/5/18 1:33 p.m.
Gunchsta said:

You GRM people are brave souls. An aging Mercedes that likes to go in limp mode screams "run far away!!" to me, but I'm excited to be proven wrong. 

I put my s600 into limp mode simply by reseating the cable connection on the TCU.  My CL constantly went into limp mode because of a bad auto trans shift module.  Sometimes the cause isn’t bad,  but STAR diagnostics is almost a requirement for troubleshooting and resetting odd things like that.


- a_florida_man:  you can pickup a clone STAR setup,  laptop and all for ~$600.

RedGT Dork
12/5/18 1:53 p.m.

I have an emotional attachment as a couple of friends and I had a little too much fun with one of these that we borrowed from a friend's parent in about 2003.  They'll reach speeds that a teenager should never travel at, that's for sure.

a_florida_man Reader
12/5/18 9:09 p.m.

Project cars always look good on the trailer....

.....at night

at the gas station.

jfryjfry HalfDork
12/5/18 11:26 p.m.

May I, off-topically, suggest considering wheel straps to secure vehicles?? 

It makes strapping them down super easy and fast, minimal mess, and it lets the car’s suspension take the bumps and not the tiedowns.  

Ive been using them for over a decade with no scratched or marred wheels and no problems. 

Hopefully you can say that last part about this car after 10 years :)

a_florida_man Reader
12/26/18 8:28 p.m.

Sooo.... I got tired of waiting for my carsoft v12 multiplexer to arrive from Belgum, so I decided to poke at the MB with sticks. Or at least that's what I feels like to me when you can't access the REAL data stream. 


The problems that were presenting were:

No top operation.

No Horn

Signal Bulb Indicator On

Transmission in limp mode (2nd gear only).

ABS/ASR lights on

Brake wear sensor lit.

Codes P1747 No CAN BUS Data to Transmission 

            P0500 Speed Sensor A Error


So I jacked up the car and pulled the wheels for the first time, and found that there was a new wheel speed sensor on the front left. MMMMMkay

I also found that the RF brake wear sensor wire was broken.

I fixed that with two waterproof butt splices. $0.20 lol.

I have spent a lot of time reading on SLK and MB forums about issues that are common on these cars.

This led me to pull the k40 relay box. This is a relay board that essentially does the job of 5 relays and fuses. Nothing complicated, but it is annoying to have 5x the chance of failure.... anyway.

When I turned the car "on" only one relay closed. Interesting.

However, on the dash, the brake wear indicator was now out.

Good news.


I checked for 12v signals at the relay coils and 3 were actually being commanded on.

I knew the horn did not work.  I actuated the relay for the horn. BEEP!

Good News.


I checked and one of the non responsive relays was for the TCU  circuit.

I closed it manually and immediately the engine ran better.

Good News.


I held it shut with some cardboard and cycled the engine off and back on.

The  brake warning light went out and via the generic OBDII scan tool I read that the two codes were now clear.

Since it was up on stands, I put it in drive. It shifted 5 times.

GREAT news.


Next I tried the convertible hardtop, and whhhrrriiirr  click click buzz whhrrrhhrr clunk, it disappeared into the trunk.

Outstanding news.


That's a lot of stuff off of the list.

For the final fix I will either repair, modify, or replace the k40 Relay Module.

To reconcile the PO's experience.... they were being told that there was a wiring problem "between the sensor and the computer". That was wrong, and it is what happens when you use generic OBDII codes on an older German car. ( I also have a z3). LOTS of stuff gets lost in the translation. The REAL tools use OEM proprietary connections under the hood to access ALL of the modules.

 So a lot of time and $$ in parts I suspect had been tossed at the big issue (limp mode) until the owners just gave up. In the end it was just a bad relay that wasn't turning the TCU on. If the TCU wasn't on, it could not talk on the CAN bus (P1747) and report a speed (P0500). 

On top of all of that, the first step in the roof module logic is to make sure the car is not moving, and with no speed reported, it would just shut down and not open the roof.

The ABS/ASR lights are still on but I think that there is a good chance that they may only need to be reset with the proper CARSOFT interface now that the transmission reports a speed.

In the end it looks like this is going to be a GRM Gastropod entry for sure.

$1000.20 for the car and repairs to date..... now what's next?


grover HalfDork
12/26/18 8:39 p.m.

Holy crap. That’s a legendary win in my book. 

Pete Gossett
Pete Gossett MegaDork
12/26/18 8:41 p.m.

In reply to a_florida_man :



irish44j MegaDork
12/26/18 9:00 p.m.

I'm amazed that a car company would build a vehicle in which so many things can be made to fail literally due to one point of failure. Wow. Good on you figuring it all out, though. Makes perfect sense. 

AnthonyGS HalfDork
12/26/18 9:14 p.m.
a_florida_man said:

Project cars always look good on the trailer....

.....at night

at the gas station.

I nominate this as Seth's next T-shirt project......  silhouette of some miscellaneous car with the text beneath it.....  "Project cars.... always look good.... on a trailer..... at night.... at the gas station."    I'd totally rock one of these at the challenge and have photos to boot.

challenge (project) car looking good on a trailer at night at the gas station.....  in Wichita, KS.  I told you I had pictures.

Cotton PowerDork
12/26/18 10:27 p.m.

Awesome work.  I had similar issues with my cl600 and got the doom and gloom speech from so many people,  but at the end of the day they are just cars,  complicated cars,  but once you start understanding the systems it isn’t that bad.  

a_florida_man Reader
12/26/18 10:34 p.m.

In reply to Cotton :

Exactly. Sometimes I think that we forget how much we just intrinsically know about common cars in the US. When an odd one comes around, it's not necessarily a worse design, I just presents a few more unknowns...

My Z3 was the same story. Just had to take some more time thinking logically and absorbing some of the features.

Many times the problems in diagnosing an issue are due to false assumptions. I commonly go back and ask myself, what do i REALLY know, and then BAM. Done.

a_florida_man Reader
12/27/18 7:14 p.m.

Its a driver! Tagged and on the road. Drives good, rattles and clunks a little, but mostly solid and sort of peppy.

35 miles round trip to the gas station, LOWES and back. 

Here's proof!


Indy-Guy UltraDork
12/27/18 7:25 p.m.

Huge win. Happy to hear that it was a simple fix.

dculberson UltimaDork
12/27/18 7:31 p.m.

Hell yeah!

a_florida_man Reader
12/27/18 7:46 p.m.

So, to start a discussion:

Considering the low purchase price and easy repair.... I think I'm in Gastropod Class Territory.

In both $$ and spirit.

I think that it needs to be lowered, a LOT. Like 2".

It certainly needs shocks.

Apparently you can go with 225 tires all the way around...

But my biggest question is how do tuners mod the ECU parameters?

I know how to do it with GM stuff, but MB is still a mystery.

I think a big thing to pursue is removing the rev limiter from the ECU code.

"Tuners" on the internet do it... 

Anyone out there in the hive ever play around with these at all?

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