jallej

Occasionally when I go over a speed bump or take a tight turn the ABC light comes on the dash, then goes out. Found the fluid dirty, so recently replaced the ABC filter and flushed the system with proper fluid. Still have same symptom. When pull codes: 1) 552540 - [HISTORY] [64] System pressure too low; 2) 552580 [HISTORY] [128] The variant of control unit Engine or control unit N73 (EIS [EZS] control unit) is not compatible with control unit N51/2 (ABC Control Module).

No driving issues; suspension appears to be operating properly. ABC pump replaced about 30K ago.

Any ideas?

Thank you.

jallej

Posted this about a month ago. I received no suggestions from this forum. In the meantime, I contacted my local dealer; they were unable to advise concerning the 2 codes 1) 552540 and 2) 552580. Car drives fine, just had issue with ABC light coming on dash occasionally when I go over a bump or on a tight turn. then immediately goes off. So, I did some additional research online and found the solution! Replaced the front axle and rear axle ABC accumulators (220 327 01 15). I used the Corteco 80001406 replacement. Today drove my SL on a day trip to Crater Lake; no ABC light on! So, after about 200 miles of driving, curves and many bumps in the road, no ABC light on and everything operating properly.

For those of you interested in very informative information concerning the ABC system, I refer you to this Mercedes Benz ABC System Troubleshooting Guide:
https://mercedes-abc-drive-carefully...y-part-of.html

Happy and safe driving!

I FAR I

Now, THIS is great forum consideration and etiquette!

The post contains some very helpful and insightful followup information with a proven solution to the problem.

Plus, the link to the ABC Troubleshooting Guide was an especially nice addition as it is certainly the single most comprehensive document I have ever seen regarding the Mercedes Benz ABC Suspension Systems. And I have the Star Diagnostic DVD.

The author of the blog, Darren Bruxvoort, should be applauded and commended for his thorough research and hard work.

It is a real treasure!

Thank you kindly, Jallej... Cheers to you and Darren!!

tonylinc

I apologize that I missed seeing the first post with the question or I would have responded saying just what he's found out. The front and rear accumulators are parts that are going to wear out eventually. Mine were worn out and I replaced both those and also the pulsation dampener too, I think the three parts cost about $800. Car is like new now and perfect. Very happy to hear that your car is well again. If your ABC is giving intermittent warnings get those parts and replace them! I waited a little too long and the pressure spikes will kill a high pressure hose and then you also need that replaced. This happened to me, and dealership wanted $9000 to replace that hose, saying it takes over 30 hours labor to disassemble most of the front of the car to replace that hose. It's called the Car Killer Hose because of the cost to replace that S.O.B. !!!
An indy shop that does the repair the same way as dealer quoted $5000. I found a local shop owned by two brothers who are engineers and they said, "SURE, we can do that, for two grand. We've done about A DOZEN of those R230s and not one of them has had a problem since." Instead of disassembling so much of the front of the car, they remove the old hose, get a new hose, install the ends, as pigtails cut off at the right length, then thread new hose in the original pathway and use hydraulic hose splicers (rated at over 7000PSI) and VOILA, hydraulic hose replaced with better than-new. I said, "I have the accumulators and pulsation dampener plus 2 motor mounts and a tranny mount, in the trunk, can you install those too?" "SURE, all that for another grand." One day after they received the car, it was all done and ready, the bill was $2900 (plus I had spent about $1000 for all my new parts I had bought) and the car is perfect. If you're young and in good shape you could probably do this work yourself and save even more money, But I'm happy I found these guys. Lucky to find this indy shop with highly capable engineers who are awesome mechanics! They are truly great. I'm kinda glad it all happened this way because that hose was the weakest link, and might have been getting ready to blow anyhow, this being a 2003 SL55 AMG with 92k miles on it. Now, it's got a new lease on life and the car is VERY HAPPY.