BAS, ESP and ABS light came on

[farmerjunglejoe]

my E320 all wheel drive wagon with 209000 miles just had the BAS,ESP and ABS warning light come on, Im thinking its a relay, would appreciate your help and knowledge, thank you, Joe

[jcyuhn]

Probably simpler than that. The two most common causes are a failed brake pedal switch or a battery on the verge of going out. The former is diagnosed if the warnings occur always when you step on the brakes. The latter is more random in timing. Have the battery and charging system evaluated; replace the battery if it's more than 5 years of age.

[davidmash]

Same issues on my Dads 2002 E320. Th battery is only two years old though.

[MikeTangas]

Wife had the same complaint with her 2002 CLK320. With her car it turned out to be a bad alternator.

After replacing the alternator and recharging the battery all the MILs went out except the ESP. That had to manually reset by turning the steering wheel stop to stop KOEO.

[SD300]

My Bro has a 98 e320, the ABS and another light stayed on, we're told the sensor could be not working,
tonite i had pulled 1 wheel, i have located the sensor, wanted to un-plug her to check for continuity, but the plug kind of hard to figure out how to remove it.
We can see it on both sides, inside the wheel well and outside, but it seem to need some special tool or way to unplug it.
now i want to ask the best & brightest as how to unplug it and be able to test it.

[davidmash]

Problem solved. Seems at least in this case it was a faulty/stuck brake switch behind the brake pedal. My brother said this will be the third one he put on the car.