gaazmon

So, I've owned my 09 SL550 for about 2 years now. I noticed some knocking noise coming from the right side (when facing the vehicle's front) on startup. After some time there was a groaning sound with vibration with the RPM rise. I diagnosed it as the ABC pulsation damper and had it replaced with part number 000-466-04-00-80. I also had my indy perform a fluid change and filter replacement. The vibration and groaning sounds are all gone now. However, couple of issues remain:

1. The knocking noise on start up is still there, but not as often (assume now the pump itself is actually bad).
2. The rear of the car slams down when I go through even a small dip or over a speed bump.

Could both issues be related to the pump or would the second issue be caused by something else? When replacing the pump would I have to change the filter and fluid again? Also, can anyone recommend what refurbished pump they have used and their experience (I assume I can reuse the new damper on a refurbished pump since the ones I've seen online don't seem to come with one based on the pictures). Also, is SDS the only device that can perform a rodeo test or do some others such as the higher end iCarSoft units do this (I have an i980 unit on hand).

The rear tires are a few years old age wise (not thread wise), but don't think that would be a cause for the slamming effect.

matk

The i980 will only display and clear fault codes, it won’t run system test routines.

bobterry99

I would discern whether or not an acceleration sensor could be causing an errant response from ABC. To do this I would disable ABC and drive the car over a speed bump. You disable ABC by pulling the fuse which supplies power to the controller, or you can remove the electrical connection to any sensor.

gaazmon

Makes sense since it's the lower tier scanner they have. Do any of the non-SDS units out there run test routines such as Rodeo or allow for disabling SBC?

That makes sense. As I said before, I only "feel it" on the rear. I drove the car again yesterday and the front is smooth going over bumps and dips while the rear just comes down too fast when there's space between the tires and the road. I'll look up the fuse diagram and try that then. Thank you.

Dudeman

If by "slams down" you mean the suspension bottoms out and you get the red ABC drive carefully, then you most likely have a bad accumulator.

gaazmon

That was my first guess, but I don't get any sort of message or anything on the cluster.

Dudeman

I used to have a 05 Sl500 and it gave all kinds of messages, like for example "car is being raised" when pushing the ABC button to raise or lower the car, also I would get the "ABC Drive Carefully" when I would go over speed bumps fast or over dips in the road. My new(er) 07 SL550 does not. Apparently some of the "warning" or informational message have been removed from the new firmware. This has been confirmed by others like Rudeney.

So maybe this is one of those newer firmware versions that doesn't give you any messages unless it's an outright failure.

As for my 05 SL500, once I replaced the accumulators, the bottoming out stopped, and so did the warning messages.

Rudeney

The original ABC system would give you messages on the MFD even during normal operation, such as "car is being raised" when selecting a ride height with the console switch. The revised (MY2007+) system only displays messages when their is a problem. On it, if you see a "car is being raised" message, it means that it had dropped to below the acceptable level due to some sort of failure or error. You will still get the white "drive carefully" and message if it detects low fluid or the red "STOP ENGINE!" message when pressure drops below an acceptable level.

gaazmon

Sorry for the delay as I have not been attentive to this issue. I notice there are two fuses for "ABC control unit" according to the charts: 15 amp in drivers side fuse box AND 5 amp in passengers side fuse box. Should I remove both or one at a time or just one of them? Doesn't state what the differences are anywhere.

bobterry99

Send me a PM for further assistance.

seven_out

I don't have documentation for your model year. Rodney or Plutoe could tell you. But if it were me, I wouldn't hesitate to disconnect the systems battery in the boot.

matk

I think the Foxwell NT510 could help here, see my separate thread on it

seven_out

Star Diagnosis has more capabilities than the Foxwell, but with respect to features that you want and need to maintain an M-B it seems to be every bit the equal of Star Diagnosis. I have Star Diagnosis, but I'm thinking of getting the Foxwell for its practicality in having a good diagnostic too in the glove box of my car all the time.

gaazmon

Bob it looks like your advice worked. I pulled both fuses, started the car (got all kinds of messages as I'd expect), turned off, put the fuses back, started again (no messages). So far it seems smoother over the bumps and uneven roads. Didn't get to drive it too much recently, but will pay attention again the next time I take her out. As always, appreciate everyone's help on here. Such a wealth of information and experience.