SL/R230: lots of codes - Seeking potential explanation
Thread Starter
Junior Member
Joined: Jun 2025
Posts: 26
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From: Phoenix, AZ
2001 CL55 and 2002 SL500
lots of codes - Seeking potential explanation
I looked at a 2003 R230 with 55k miles on it today. Beforehand, I was aware of a top and ABC issue. I am willing to accept a challenge for the right opportunity. Well I put my launch scan tool on it and it came back with a ton of codes. I have the list attached. At the same time, the Red Battery alert was on the instrument cluster display. Per the seller, the rear battery was just replaced. The front battery is from 12/22. The scan tool gave me a reading of 12.9 volts. Many of the codes reference "Fault in Can Communication", "Undervoltage Supply" and a few "Short Circuit" references. I realize that sometimes these codes surface when battery is disconnected and clearing may address. I didn't try that, as it is not my car. At the same time, I dont recall losing some functionality under that scenario.
Can such behavior be attributed to the failure of one component? If so, whats your guess as to the culprit? The seller was amazed that I had found what I did and was shocked when multiple components werent functioning. He's a car collector with multiple MB's and he has owned this SL for the past two years and supposedly bought it from his uncle, so I am leaning that many of these issues are new and related. Interested to hear your thoughts
Can such behavior be attributed to the failure of one component? If so, whats your guess as to the culprit? The seller was amazed that I had found what I did and was shocked when multiple components werent functioning. He's a car collector with multiple MB's and he has owned this SL for the past two years and supposedly bought it from his uncle, so I am leaning that many of these issues are new and related. Interested to hear your thoughts
Super Member
Joined: Sep 2021
Posts: 537
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From: Ann Arbor, MI
2004 SL600
I looked over the codes. Many/most are due to a previous low voltage condition.
IMHO, you need to reset the codes, start the car, drive at least around the block and check for codes again.
The ABC "Low Pressure" code will be a concern if it comes back, which is likely. All the other ABC codes are due to the low pressure.
IMHO, you need to reset the codes, start the car, drive at least around the block and check for codes again.
The ABC "Low Pressure" code will be a concern if it comes back, which is likely. All the other ABC codes are due to the low pressure.
Super Member
Joined: Sep 2019
Posts: 622
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From: My house
SL55AMG, GL450, SLK, S550, Maserati Coupe
Many times a repair is done and the code is left in there and so a car can have a lot of codes that are for problems that have already been alleviated. Mrvedit is right. One thing I would do is have a look at that battery in the trunk, to see that it is a correct battery for the car. There's never a guarantee that a previous owner has used correct parts when doing a repair... When I bought my SL55, the trunk battery was indeed 2 months new, but it was not an AGM!! It needs to be an AGM type battery, sometimes apparently people who don't know what they're doing will install a wrong battery. I took $250 off the purchase price of the car and went out and bought a brand new AGM battery the first day.
Last edited by tonylinc; Dec 14, 2025 at 01:44 PM.
Thread Starter
Junior Member
Joined: Jun 2025
Posts: 26
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From: Phoenix, AZ
2001 CL55 and 2002 SL500
Thank you for all your input. I am in Phoenix, AZ, I will update my profile to reflect that.
I do have my suspiciions regarding the installed battery. Yes it is new, but it is a Duralast suggesting owner install. Not sure if it is the proper AGM battery.
WIth the ABC, top and electrical codes the car has issues. I am trying to decide if its worth the effort to make an offer to take it off his hands. He is motivated and I am fairly willing to accept a challenge. I am more nervous about the apparent electrical gremlins than the ABC and top as I have sorted the ABC on my CL and there's decent documentation available to sort thru the top issues.
I do have my suspiciions regarding the installed battery. Yes it is new, but it is a Duralast suggesting owner install. Not sure if it is the proper AGM battery.
WIth the ABC, top and electrical codes the car has issues. I am trying to decide if its worth the effort to make an offer to take it off his hands. He is motivated and I am fairly willing to accept a challenge. I am more nervous about the apparent electrical gremlins than the ABC and top as I have sorted the ABC on my CL and there's decent documentation available to sort thru the top issues.
Super Member
Joined: Sep 2021
Posts: 537
Likes: 116
From: Ann Arbor, MI
2004 SL600
Lots of us use Duralast or similar batteries. Since its reading 12.9 volts, you are fine.
Fortunately you are in a big city where there are many similar cars, independent shops and likely plenty of expertise.
Your decision comes down to how much you want the car, price and you willingness to fix things. Likely figure it going to cost another $3000-$5000 in the first year to get it working very vell.
What engine model are you looking at?
Fortunately you are in a big city where there are many similar cars, independent shops and likely plenty of expertise.
Your decision comes down to how much you want the car, price and you willingness to fix things. Likely figure it going to cost another $3000-$5000 in the first year to get it working very vell.
What engine model are you looking at?
Thread Starter
Junior Member
Joined: Jun 2025
Posts: 26
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From: Phoenix, AZ
2001 CL55 and 2002 SL500
Its an SL500 2003. I am figuing the same on the $3-5K to get things straightend out. It has a good maintenance history so fairly comfortable that the issues should be pretty much limited to those identified above. I have sorted a bunch of cars over the years. Electronics is what concerns me most, as I dont have much experience with it..
