ASR Problem

[bdelmonico]

92 500sl running fine went away for 4 days came back battery was a little low, maybe more then a little low car was not previously driven for a week or so, any way came back started car and ASR light came on went into limp mode in the garage??? QUESTION: can a low batter cause this light and limp mode???

[97 SL320]

I have had batteries that droop too much during cranking cause all sorts of issues. When voltage drops too much, computers can operate improperly. A general sign is losing radio settings / digital clock resetting.

Measure battery voltage after the car has been sitting for 8 hours. ( not charging or discharging.) I'd call 12.2 getting low for an electronic laden car.
12.66 is full charge
12.42 is 75%
12.18 is 50%
11.94 is 25%
11.70 is 0%

This is state of charge only and not if the battery has worn out. As a battery wears out it will get "smaller" in capacity. Only way to test capacity is with a load tester.

Also, a shorted cell will give a 10 V battery that will crank slow but for an extended period of time.

[bdelmonico]

You know U may be right. I just charged the battery up and I tested it and it read 13 v the next day I ck it again and it read 12v so may be the ASR light came on because my Battery is JUNK? I will take the battery to get it tested. Thanks for the come back I do appreciated it and U may have saved me a TON of $ I will advise when I get it checked. Thanks!

[bdelmonico]

Well, took the battery and had it checked. They say it is good?? 12.9v? So, it looks like I am back to sq 1

[97 SL320]

Did they check the battery with a load ( big jumper cable type cables / clamps ) or a small voltage only tester ( small multi meter sized wires )?

A battery can develop a bad internal connection that will fail under load but look OK with a voltage only test.

[bdelmonico]

Ya, big black Jumper type cable and he pressed several buttons which I assume puts the load on it. He said it was good? Battery is 4 yr old? I thing it is the Battery myself But I do not want to go throw 100 bucks out the window. Do you think it could be a OVPr fuse? I think the issue is got some thing to do with the electrical. I mean the dam car was running good and I parked it and started it w/ a low battery a week or so latter and the dam ASR light would not go out. Now it going to be a giant head ache to tow the car 100 miles to get serviced/fixed

any other thoughts on what I might be able to ck. I did the fuses except ovpr

[97 SL320]

If load tested, the battery will be OK. Is there a way to find out the make model of the tester to make sure it is a load tester? I don't know why it is stuck in limp mode. What are the specific symptoms?

At this point you need to make a diagnostic tester out of an LED , resistor , switch and 3 banana plugs. Somewhere on this site there are diagrams, search for "analog tester" "led tester", "blink tester" or similar. I have a 91 300SL parts car but have not tested any systems so you will need the help of others. ( My 97 is digital and uses a 38 pin connector where yours has a couple of 9 and 16 ish pin connectors )

Post your troubles on the Tech portion of the forum as other cars use the same tester.

[bdelmonico]

Thanks, however, I have very little tech abilities and I think the ol gal needs to go see her doc in Las Vegas. If it was a fuse or some simple little thing I could handle it but beyond fuses I am lost. Thanks for assistance!