The supercharger on my 1999 SLK230 stopped working and my OBD II reader showed P1235, P1236, P1420 and P1525 codes. Thanks to this and other forums I was able to narrow it down to K40 relay (THANKS, I REALLY APPRECIATE ALL THE VALUABLE INFO!!!).

Two days ago I disconnected the battery (negative terminal) and removed the K40 Relay. Sure enough I found a bad/burnt connection and re-soldered it. Today, I re-connected all plugs to the K40 relay and re-connected the battery. When I sat inside the car I noticed the lights illuminating the clock, mileage and outside temp being "ON" (please see attached pics) and heard a continuous "beeping" coming from the dash. Gas gauge and engine temp needles DO move and stay at different position every time.

I started the engine and it runs fine. No "Check engine light" and no fault codes on the OBD II reader. Air pump engaged right away and it stayed on for some time. No RPM gauge readings. I took the car for a ride and it seems to be running great – supercharger kicks in, even though I can’t tell at what RPMs. No speed reading either...

Any ideas? Is there anything I need to reset after I re-connect the battery? PLEASE HELP... []

Ignition Key OFF, Ignition Key ON and ENGINE RUNNING:



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Try removing Battery -ve connectiopn for a while and have another go.

If not....

EXACTLY what did you do? Any pics of what you did to the K40?

What happens with "K40" relay module disconnected?...at least from the point of view of the instrument cluster.
Sure you haven't removed, refitted or changed the instrument cluster?

I believe that the cluster memory and other module data inputs have non plausible data for some reason. Possible cause is a CAN fault somewhere on the network but where and why?

Stuart

 

Thanks Stuart. I removed the battery negative connection for 24 hoursand got the same results when I reconnected it. Tried removing the K40 relay - cluster looks the same and the beeping continued. The beeping sounds almost like some kind of alarm. Engine runs great though...

I wonder if that could be a GROUND PROBLEM of some kind. Where should I look and what should I look for? Under dash? Under the hood? Has anyone even heard of this before?


BTW, I had exactly the same issue as described in this post and the fix worked!!! I have my supercharger back... except the erratic gauges on the instr cluster...

http://www.benzworld.org/forums/r170...=1#post2052984

 

OK. Pretty sure that the problem is the instrument cluster coding.

If the speedo is changed you get a problem like this. Anti tamper feature.

How long have you had the car? Sure it couldn't have been tampered with in the last 250 miles or so?

Out of ideas now.

Stuart

 

i also suspect that the coding was changed.

 

I've had the car for more than a month, but it's been in and out of the body shop... I haven't got the chance to put more than maybe 50~60 miles at the most. Bought it locally from a private party.

How is the coding been changed and who could change it? Could it be a new ECU or cluster just being recently replaced??? The beeping sound definitely seems like some kind of alarm...

So, what can I do now, or what should I do?

 

Looks like someone has fitted a different instrument cluster or possible other system module.

Was the mileage low (for the year) when you bought the car? If so maybe this was to hide the true mileage.

Need to get car onto Star Diagnostics at the dealer and recode the instrument cluster.

The dealer may be reluctant to recode without full history of what has taken place so as not to compromise the security of the mileage readout.

The system modules talk to one another and when there is an "error" between the data in one system and another an alarm is triggered....but not immediately I understand. Why there is a delay is beyond me..

However it may be something completely different.

I'm afraid you need MB DEALER diagnostics or at least someone with top end diagnostic equipment.

Stuart.

 

Thanks Stuart, I'll go in to see the stealer tomorrow and give feedback in the next few days. Appreciate all the help...

 

Good luck.
Stuart

 

$1350.00 is what the dealer is asking to replace the Instrument cluster on my 99 SLK 230.

I went to the dealer and had them replace both taillights (under a recall), check the transmission fluid level (car didn't come with ATF dipstick), requested the radio code and a full system diagnostic. I also requested a printout of the results.

There are a lot of codes there!!! Most say "STORED", and only one says "Current and stored", both on page 1. Interesting enough, instrument cluster on page4 doesn't even show an MB number...

Need help understanding all the codes/info, connection between them. Where should I begin? Should I replace the cluster first? Can I get a used one or has to be a new one? Can an independent mechanic shop program it or do I need to go back to the dealer

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