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Discussion Starter #1 (Edited)
1999 SL500-Raised and Stayng-up ADS

I have a 1999 SL500 with a height-adjustable ADS.
Recently, I replaced the front air accumulators and front bushings. And a couple days later, I found the SL500's suspension was raised as high as possible and stayed up.
After a several try of ignition on-off, the front suspension height came back to normal and adjustable by button operation, but the rear suspension stayed up high continuously.
I took the Sl500 to an authorized MB dealer and they diagnosed very expensively, saying that the SL500 needs to replace all ADS-related parts(including the ADS controller?) costing around US$8,000(such an absurd amount).

This situation just happened and I cannot figure out WHY.

ANY IDEA ON THE ABOVE SYMPTOM AND FIXING SUGGESTION?
 

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1999 SL500-Raised and Stayng-up ADS

I have a 1999 SL500 with a height-adjustable ADS.
Recently, I replaced the front air accumulators and front bushings. And a couple days later, I found the SL500's suspension was raised as high as possible and stayed up.
After a several try of ignition on-off, the front suspension height came back to normal and adjustable by button operation, but the rear suspension stayed up high continuously.
I took the Sl500 to an authorized MB dealer and they diagnosed very expensively, saying that the SL500 needs to replace all ADS-related parts(including the ADS controller?) costing around US$8,000(such an absurd amount).

This situation just happened and I cannot figure out WHY.

ANY IDEA ON THE ABOVE SYMPTOM AND FIXING SUGGESTION?
As to why it happened now, things start failing in sequence a lot of times. Once you start playing with a system on a vehicle and replacing other parts, anything you may not have noticed yet that was on the verge of failure gets pushed off the ledge... Sometimes it makes no sense, but that's just the way it works..."when it rains it pours".

As to advice on what to do, that's easy: DO NOT BUY THE ADS MODULE FROM THE DEALER

Do a google search. There are scads of automotive electronics rebuilders that can fix it for a small fraction of what the $tealer is quoting you. The downside is that your car will be inoperative for a couple weeks while you mail it off and wait to get it back.

I used one awhile ago on my BMW for the ABS controller...I think they were named Module Masters or Module Master, something like that. I am sure you can find them online.

If it's your primary vehicle and you need a quicker fix, then you can order a used one online as well.

Try silver-star recycling in arizona, or tristar parts. I know tristar is online.
 

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The dealer should have read diagnostics from the ADS control system and reported to you what they found. The results would be highly valuable in troubleshooting your problem. In the absence of that information, I believe you can check a few things easily for yourself if you have a basic electronic multimeter: the power supply to the axle level and body acceleration sensors, the feedback signals from those sensors, and the control outputs from the ADS controller to the vehicle level regulating valve. If you can't get the codes from the dealer and want help with testing, reply back or send me an email.
 

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I have a 1999 SL500 with ADS.
Welcome to the R129 Forum. An SL500 with ADS is very rare and was a costly option when new.
Would you please be so kind as to keep us updated on the outcome of your situation?

FWIW, may I suggest that you take 'bobterry99' up on his offer to help you. He is one of the most knowledgeable SL problem solvers on the R129 Forum. IMHO, this is the kind of thing that calls him to task.
 

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Discussion Starter #5
The dealer should have read diagnostics from the ADS control system and reported to you what they found. The results would be highly valuable in troubleshooting your problem. In the absence of that information, I believe you can check a few things easily for yourself if you have a basic electronic multimeter: the power supply to the axle level and body acceleration sensors, the feedback signals from those sensors, and the control outputs from the ADS controller to the vehicle level regulating valve. If you can't get the codes from the dealer and want help with testing, reply back or send me an email.

Many thanks folks for your kind replies and postings.

As bobterry99 suggests, I will get back tp the local MB dealer and get the error codes for the symptoms on my SL.

I will keep you informed and the updates posted here.

Regards

John
 

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Discussion Starter #6
ADS Error Code on my 1999 SL500

The dealer should have read diagnostics from the ADS control system and reported to you what they found. The results would be highly valuable in troubleshooting your problem. In the absence of that information, I believe you can check a few things easily for yourself if you have a basic electronic multimeter: the power supply to the axle level and body acceleration sensors, the feedback signals from those sensors, and the control outputs from the ADS controller to the vehicle level regulating valve. If you can't get the codes from the dealer and want help with testing, reply back or send me an email.
Hi!!

I obtained the ADS error code through the local MB dealer.
I scanned the printed error report and attached here.

I hope that the ADS error code report is useful to figure out the cause of problems.

regards

John
 

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The image of the diagnostic report is blurry on my PC and illegible...

If there is a code that mentions an axle level sensor, you could proceed next to replace with a new one but you might just be wasting your money. I wouldn't replace that sensor without first doing some basic testing of the circuit since the code could also be caused by faulty wiring, poor electrical connections, or a defect in the ADS electronic control module.
 

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Discussion Starter #9
Better look of the ADS error code report

Hi!!

I obtained the ADS error code through the local MB dealer.
I scanned the printed error report and attached here.

I hope that the ADS error code report is useful to figure out the cause of problems.

regards

John

I attached here enlarged looks of the ADS error report with three files.

Regards
John
 

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Execution only after narowing down the cause

Have you replaced the right-rear switch that is throwing the code?
No,I have not.

I would do proceed any ADS-related replacement or fixing only after analyzing the error report and narrowing down the cause.

I attached the error report on the above, but I am not adapt at interpreting the report and error codes.

Thanks!

John
 

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Based upon the report I would troubleshoot the control valve Y36/6y4. I would first check the wiring from the ADS control module to the valve with a basic multimeter. You remove the electrical connector to the module and measure the resistance between sockets #12 and #37. It should be 7.5-12 ohms. You may as well check the other three control valves too. They are measured between #11 and #37, #16 and #37, and #20 and #37 of the same connector.
 

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Sorry to thread hijack, however this is related.

I just changed the LCA on my 1991 500SL equipped with ADS, and unfortunately I didn't read enough about not hammering near the right front acceleration sensor mounted on the hub, and it has died on me :(

Does anyone know the part number for this item? Or does anyone who has removed ADS have on sitting in their workshop/garage doing nothing and want to sell it?

Thanks,

Richard
 

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1999 SL500-I took the Sl500 to an authorized MB dealer and they diagnosed very expensively, saying that the SL500 needs to replace all ADS-related parts(including the ADS controller?) costing around US$8,000
You may want to give 4Mercedes a call if you have questions or end up needing a reconditioned controller.
 
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