Mercedes-Benz Forum banner

ADS 1 System Problems, 013 HHTwin code

529 Views 8 Replies 4 Participants Last post by  Chris Morlock
So I have been trying to get the ADS 1 system on my 1995 sl600 back up and running again. It's been an odyssey to say the least.

When I purchased the car 6 months ago it was stuck in the tallest position with the ADS warning light on. It was very firm ride but has zero leaks anywhere and held perfect pressure even after months of being in the raised position without leaking a drop.

I scanned codes with HHTwin and got a Y53 and Y54 code plus an 013 They read exactly like this:

008 Solenoid valves RA Y53y1, Y54y1
009 Solenoid valves RA Y53y2, Y54y2
013 Supply pressure too low

I first thought about the accumulators (balls) being bad because that's what you see discussed on the forums mostly, so I purchased 4 Cortecos. I decided to change the rears out first and proceeded to find the old ones in great shape, not collapsed, and actuall Coretcos which probably had been replaced in the last couple of years. So I sent that $400 adventure back for a refund and just kept the old balls in place.

Then I decided to change out the rear valves Y53 and Y54. Ordered a used set and installed them, no change- same codes. It baffled me for a bit so I tried to trace the wires, and sure enough some idiot had disconnected one of the valve's connectors in the spare wheel well. I wish I had checked this prior to parting with another $300 for the replacement valves.

As soon as the connector was put back the Y53 and Y54 codes disappeared, and the system in HHTwin can no go into the "zero" position, meaning the three modes shown in HHTwin as comfort/O/sport. Before it was stuck in sport, now it seems to be stuck in O. I can use HHTwin to put the system into comfort mode, and the ADS warning light extinguishes immediately when I do this.

As soon as I dissconnect HHTwin the ADS warning light goes on again and baclk to square 1. The only code is the "013 Supply pressure too low".

Looked high and low to find another person with this 013 code and there is nada anywhere. I know the diagnostic trouble shooting manual STAR TekInfo
with no real lick considering all of these procedures usually has specific codes in either HHTwin or the impulse codes. I can't even find a corresponding impulse code to the "low pressure" code in HHTwin.

Really getting confused here, what's the deal? Pressure in the system seems good, and the spheres are all good, and it rides a bit better in the "zero" position. The ADS button on the dash doesn't realty do anything. Ride height is all at the tallest setting all the time but even.

My next target area would be the distribution block and of course the pump. If there is "low pressure" could this be related to the distribution block? I guess I could pull the front spheres and make sure they are still good as well.

Thanks for any help or ideas, this has been a very challenging project. If anyone has any questions I am glad to respond, I learned a lot about the system.
See less See more
1 - 2 of 9 Posts
Sorry to hear about your "odyssey". ADS 1 is simple and reliable system but sometimes challenging to diagnose.

If(?) I read you correct, your suspension is in stuck in uppermost position, ADS MIL is lit and you have DTC #013. Right?

I do not know ADS 1 had pressure sensor. DTC #13 points to oil reservoir level float. It connects to ground when oil level is ok. You can even bypass it temporarily by shorting terminals with a jumper at tank connector. The magnet that actuates the level switch is weak and therefore it can jam. A stronger magnet can be used to close the sensor switch and verify with ohmmeter if it is faulty.

When the car is in "SUV mode" (to quote GUSMB's, Sweden expression) likely cause is that oil cannot escape from struts. Either the check valves in main hydraulic valve are not correctly assembled or the level valves front/rear are stuck to "fill" position. If you move the levers manually does it have an impact? If any of the main valve 4 mm check valve balls is missing, the oil return is stopped and the car will stay up in highest position. This has been the most common issue with reported SUV-mode cases.

Pressure accumulators never throw any DTCs since they are purely hydraulic - no electrics. Impact of a ruptured accumulator is that there is no spring in the corner in question. No other symptoms.

Good luck! Pls report back.
See less See more
Just a brief update. Attached picture shows internals of the ADS oil level sensor. The active element is a reed relay. The one pictured lasted barely three decades. You could change the cheap ($1-2) relay if you could open the sensor casing without braking it.
Wood Wire Metal Gas Cable
See less See more
1 - 2 of 9 Posts