SL/R230: New to me SL550 with electrical issues
12-08-2022, 08:51 PM
#1
New to me SL550 with electrical issues
I just purchased a 2007 SL550 from a Mecum auction. It has 75K miles and I bought it for $12k.
It was delivered yesterday and had a couple of trouble codes.
Issues:
Roof would not open and close. - Fixed with replacing the the battery in the trunk
Red battery light: Checked voltage on both bats and measuring at over 12 V's. Both batteries voltage showing at 14V's while engine is running (makes me assume that charging system and voltage controls are good)
Command system - Command system turns on for about 10 seconds then I get a no "system unavailable message" and it shuts down
No signal from wheel sensors
AC compressor will not start
I have checked the voltage at both batteries with the engine off - both over 12v's. While running both are showing just over 14v's.
Headlights are strong with no dimming during start up or down.
It seems to me that it is a control issue from the Gateway control module. If that is the issue then it appears that I will have to take it to a MB dealer. I would like to avoid that if possible obviously.
Looking for advice on how to proceed.
It was delivered yesterday and had a couple of trouble codes.
Issues:
Roof would not open and close. - Fixed with replacing the the battery in the trunk
Red battery light: Checked voltage on both bats and measuring at over 12 V's. Both batteries voltage showing at 14V's while engine is running (makes me assume that charging system and voltage controls are good)
Command system - Command system turns on for about 10 seconds then I get a no "system unavailable message" and it shuts down
No signal from wheel sensors
AC compressor will not start
I have checked the voltage at both batteries with the engine off - both over 12v's. While running both are showing just over 14v's.
Headlights are strong with no dimming during start up or down.
It seems to me that it is a control issue from the Gateway control module. If that is the issue then it appears that I will have to take it to a MB dealer. I would like to avoid that if possible obviously.
Looking for advice on how to proceed.
12-08-2022, 11:52 PM
#2
Super Member
It's not uncommon to get the red battery light after a failed rear battery; it can usually be cleared after changing the battery. You say you have codes - your scanner should be able to clear the red code. If it comes back then there is another issue but you say that both batteries are charging so probably all is well with the battery and charging system.
Which wheel sensor? This could indicate a failed ABS sensor or dirty or damaged reluctor ring.
Any other codes? The car will probably have a haystack full of stored codes; clear them all out and see what comes back.
Basics first - check all the fuses in all three fuse boxes if not done already.
Which wheel sensor? This could indicate a failed ABS sensor or dirty or damaged reluctor ring.
Any other codes? The car will probably have a haystack full of stored codes; clear them all out and see what comes back.
Basics first - check all the fuses in all three fuse boxes if not done already.
12-09-2022, 05:42 AM
#3
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I just purchased a 2007 SL550 from a Mecum auction. It has 75K miles and I bought it for $12k.
It was delivered yesterday and had a couple of trouble codes.
Issues:
Roof would not open and close. - Fixed with replacing the the battery in the trunk
Red battery light: Checked voltage on both bats and measuring at over 12 V's. Both batteries voltage showing at 14V's while engine is running (makes me assume that charging system and voltage controls are good)
Command system - Command system turns on for about 10 seconds then I get a no "system unavailable message" and it shuts down
No signal from wheel sensors
AC compressor will not start
I have checked the voltage at both batteries with the engine off - both over 12v's. While running both are showing just over 14v's.
Headlights are strong with no dimming during start up or down.
It seems to me that it is a control issue from the Gateway control module. If that is the issue then it appears that I will have to take it to a MB dealer. I would like to avoid that if possible obviously.
Looking for advice on how to proceed.
It was delivered yesterday and had a couple of trouble codes.
Issues:
Roof would not open and close. - Fixed with replacing the the battery in the trunk
Red battery light: Checked voltage on both bats and measuring at over 12 V's. Both batteries voltage showing at 14V's while engine is running (makes me assume that charging system and voltage controls are good)
Command system - Command system turns on for about 10 seconds then I get a no "system unavailable message" and it shuts down
No signal from wheel sensors
AC compressor will not start
I have checked the voltage at both batteries with the engine off - both over 12v's. While running both are showing just over 14v's.
Headlights are strong with no dimming during start up or down.
It seems to me that it is a control issue from the Gateway control module. If that is the issue then it appears that I will have to take it to a MB dealer. I would like to avoid that if possible obviously.
Looking for advice on how to proceed.
I solve these case every week
12-09-2022, 11:37 AM
#4
It's not uncommon to get the red battery light after a failed rear battery; it can usually be cleared after changing the battery. You say you have codes - your scanner should be able to clear the red code. If it comes back then there is another issue but you say that both batteries are charging so probably all is well with the battery and charging system.
Which wheel sensor? This could indicate a failed ABS sensor or dirty or damaged reluctor ring.
Any other codes? The car will probably have a haystack full of stored codes; clear them all out and see what comes back.
Basics first - check all the fuses in all three fuse boxes if not done already.
Which wheel sensor? This could indicate a failed ABS sensor or dirty or damaged reluctor ring.
Any other codes? The car will probably have a haystack full of stored codes; clear them all out and see what comes back.
Basics first - check all the fuses in all three fuse boxes if not done already.
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BenzNinja (12-09-2022)
12-09-2022, 01:30 PM
#6
MBWorld Fanatic!
12-09-2022, 08:31 PM
#7
Senior Member
When the AC system shuts down due to low refrigerant, it must be reset to become operable again. Many times an AC compressor gets misdiagnosed as bad because the AC remains inoperable after refilling refrigerant when in reality all that is wrong is the system was never reset.
