ML500 ESP/BAS Problem - PeachParts Mercedes-Benz Forum

mbsickness · #1 09-09-2006, 02:58 AM

Hello all, i have a 2002 ML500 which I have been having problems with the BAS/ESP warning light. I took the car to the dealer and the SDS returned codes C1000, C1042, C1022 and C1040. A new ESP/BAS control module was ordered and later installed. Fast forward one month. The light is back....intermitantly of course, about once a day after driving for a while. Took it back to the dealer today and when scaned with the SDS....no codes. Are there any faults that result in a code but get erased when the ignition is shut off? I love this truck but this is becoming a real hassle.

G-Benz · #2 09-09-2006, 07:43 AM

Your techs should know this already, but the stop lamp switch (about $25) will intermittently throw codes that will set off the ESP/BAS light. Also when it does, at least three codes get stored.

My 99 ML320 had this ailment, and the stop lamp switch replacement cured the problem.

This issue exists for other models as well. Just this week, I picked up my wife's 01 CLK from the dealer because it threw three codes and lit up the ESP/BAS light for the EXACT same thing. The fix? The stop lamp switch...

mbsickness · #3 09-09-2006, 11:08 AM

Thanks for your reply. The first time the car when in to the shop it threw the four codes listed. Most recently the light comes on but there are no codes stored. Since there are no codes, they say everything is "normal".

azinn · #4 09-09-2006, 12:41 PM

Quote:

Originally Posted by mbsickness

Thanks for your reply. The first time the car when in to the shop it threw the four codes listed. Most recently the light comes on but there are no codes stored. Since there are no codes, they say everything is "normal".

Brake light switch......... easy DIY http://www.benzworld.org/forums/w163-m-class/1166641-ets-bas-warning-light-fix.html?highlight=brake+light+switch

david s poole · #5 09-09-2006, 02:02 PM

just make absolutely sure that you buy a genuine switch from the dealer.you will regret it if you don't.

mbsickness · #6 09-09-2006, 05:26 PM

They checked the brake light switch adjustment and said if the switch were faulty it would have set a code...or is there an instance where the switch will trigger the light and not set a code?

Also on the owrkorder they checked voltage supply and the battery. Just a thought....could a bad alternator/voltage regulator cause this issue?

ILUVMILS · #7 09-09-2006, 11:16 AM

Yeah, the brake light switch is definitely the most common cause of ESP/BAS malfunctions, but it will store a fault code. One of the lesser known culprits is the vehicle battery. I've had a handful of stubborn cars over the years that gave VERY intermittent ESP/BAS warnings. All other electrical functions were normal. In these cases the warning lights came on immediately following engine start. Switching off the engine and re-starting caused the lights to go off. I don't know if this information will help, since you say the light comes on after driving for awhile, but it's easy enough to check. Good luck