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2001 ML430
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Discussion Starter #1
As the title said, in short, I need to get the wiring pinout diagram for the transmission connector.

Now for the long answer. I am trying to come up with an easy way to calibrate the speedometer on our beloved ML's when we install larger off road tires. I am an engineer, machinist and mechanic. Sometimes this gets me in trouble. Anyway, I know the speedometer is driven from one of the computers via CAN, which unless you can rewrite the coding, there is no easy way to calibrate the speedometer. But, the signal has to get to the computer in a PPM format (Pulses Per Mile) like every other electronic vehicle for the last 20 odd years. The PPM signal can be altered by using one of a few devices like a speedohealer made for motorcycles to do the same thing. It intercepts the PPM and allows you to either slow it down, or amplify it depending on which way you need to adjust it. These devices can be had for about $75-$125.

I want to intercept the signal from the transmission before it enters the computer and is converted to a CAN signal. If I am successful, it will allow us to infinitely adjust our speedos for any tire size installed. The computer would be none the wiser.

So, either I need the pinout from the transmission, or a pinout of where the signal enters whatever computer module it goes into (probably the transmission computer). I will make any findings I discover public on this forum.

Thanks
Jay
 

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2001 ML430
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Discussion Starter #2
Crap, forgot. My rig is a 2001 ML430, but this information is probably generic for all W163s.
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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Translation: you can do it but you'll need to apply something like that speedoheal on all four ABS sensors.

At least older cars were simpler, W210 for instance, the rear left wheel was used as signal for the speedometer.
 

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2001 ML430
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Discussion Starter #5
Crap. I was hoping it was a simple speed sensor in the transmission. Back to the drawing board.
 

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Another thought. Since VSS used for transmission gear ratio monitoring altering that signal may lead to false faults in transmission control module.

I am sure somebody with developer version of SDS could make such correction in cluster itself.
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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Technically you could do that by adjusting the final gear ratio with the larger wheels and inputting that in the IC.
 

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2001 ML430
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Discussion Starter #8
I do not have the software to program the computer. I Bought one of those chinese copies of the dealer software a few years ago and blew about $500 on it and it never worked. Of course, could get no support on it so I was screwed.
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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If you have a SDS along with the C3/C4 mux then you could get it working.

There is no programming necessary -- all you're changing is the coding.
 

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2001 ML430
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Discussion Starter #10
I have the software, but the hardware I bought was junk, so I tossed it. Someday I will try and find another one.
 

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2003 C320 coupe, 2000 ML320
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Have you thought about just modifying the meter movement itself and leaving everything else as it is ? It would seem to be a whole lot simpler and less intrusive.. Put a diff. opp. amp between driver and meter movement..
 

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Discussion Starter #12
That is an option, but would love the odometer to be accurate as well. But maybe you have something here. I might go buy a cluster from the pick a part and tear into it and see what my options are.

I am also going to go stop by a local indy euro repair shop in town that I know are very fond of ML's. I am going to ask them to poke around in the mercedes software and see if they can find a place to calibrate the speedo in coding.
 

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Discussion Starter #13
If you have a SDS along with the C3/C4 mux then you could get it working.

There is no programming necessary -- all you're changing is the coding.
Deplore,
Do you have any information on where in the SDS is the place where we can adjust the gear ratios. I have a shop locally willing to give it a shot but he said he could not find anyplace in the software to do it.
 

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Deplore,
Do you have any information on where in the SDS is the place where we can adjust the gear ratios. I have a shop locally willing to give it a shot but he said he could not find anyplace in the software to do it.
I have looked all over and cannot find it. For instrument cluster coding DAS invokes HHT-Win. There is nothing there about gear ratios. I run oversize tires on my ML350 so my speed and odometer are 8% under.
 

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1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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You would be looking into esp and ECU coding, not cluster. In ECU, you'll be inputting your final gear ratio (3.07 or 2.82) but with oversized tires you'll have to do some calculation and input the number that would come out closest to that.

Esp, you'll be doing same thing. On 163 it'll be through DAS, not httwin.

You'll most likely be going through developer menu, in German language.

I'll have to putter around tonight in simulation and see where's what.
 

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You would be looking into esp and ECU coding, not cluster. In ECU, you'll be inputting your final gear ratio (3.07 or 2.82) but with oversized tires you'll have to do some calculation and input the number that would come out closest to that.

Esp, you'll be doing same thing. On 163 it'll be through DAS, not httwin.

You'll most likely be going through developer menu, in German language.

I'll have to putter around tonight in simulation and see where's what.
Since 722.6 does not have output shaft speed sensor gear ratio evaluation is done by comparing input, turbine and VSS. Seams like altering diff ratios would brake that function.
 

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1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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No, it just moves the shift points. You see this in 203, 210 and 220. 203 with M111 uses 3.46 whereas 203 with 5.4 M113 uses 2.87. By inputting the final ratio, the module will move the shift point up or down the engine rpm range.

Of course there will be other issues, but for the most part the TCM won't complain too much since as you said, the speed output is gotten from the abs sensors. 722.9 has output speed sensor and is now fully independent.

Puttered around in simulation, and it's woefully limited. But I think it's located in adaptation, variant coding, read coding and change if necessary.

In ABS, ESP, I didn't see anywhere in the regular menu, maybe in developer menu, but since simulation, it was limited and couldn't show me. I'll have to get my car this week and check it out.
 
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