so out of the blue my car suddenly needs alot of work , engine mounts died, engine light on, , just got the brakes done , and due to them not balancing rotors the sway bar broke off the body when the car began to vibrate under braking. but now my main issue is the ABS and ESP light on , no idea why, my engine light is also on but im thinking it just needs the RCM looked at. which i will deal with. the braking seems fine , just that darn light! and a final symptom which arose yesterday which i don't feel is related , while accelerating from a stop , the second the car goes into second gear and hits 2000 rpm, the car gets a burst of power that hold up until 3000-3100 rpm then resumes normal power band, enough of a power boost it pushes you into your seat slightly . it caught me off guard the first few times. but what a surprise it was! any ideas for my brakes?

 

have you had someone read diagnostic codes? that's always the first step.

 

i was told the they could not diagnose those issues through the obd 2, is this true?

 

You can get the engine fault code with a reader thru the OBDII connector under the dash.

 

the code we got is this p20cb, and or p0500

 

P0500 = Vehicle Speed Sensor Malfunction

Don't see a p20cb ??

Here is the complete list of trouble codes for reference

Diagnostic Trouble Code (DTC) List

 

how do we figure out which speed sensor has gone out?

 

so i took it back to the shop and they claimed it was pack rats ating my cables, they claimed they fixed it. lights are still on , but now she randomly goes into limp mode.. im quite confused and dont know what to do, suggestions guys?

 

Only one, stop going to that shop.

 

Non-specific statements annoy me, get them to tell you what cables were damaged.
And "fixed it" tells you nothing - did they put in a new harness or did they just insulate the damaged areas? Did they splice in replacement wires?

The poor training the industry provides for these "technicians" when it comes to electrical problems make it very hard for "technicians" to fix any electrical problem in the car. And yours certainly sounds like electrical problems.

The ABS light can come on due to a weak battery or corroded battery terminals or cables. In fact, a whole LOT of issues can be caused by bad batteries or bad connections to the battery.

 

i thought the same about not going back , but they have treated all my cars well for many years now, they even admitted finally this car was beyond their scope. they also told me after asking that it was the front passenger side speed sensor cable, they simply spliced in new wire, instead of a new harness, the battery seems fine, especially since it was replaced about a year ago, could it be bad so soon? they also said they allowed a newer technician work on my car which isnt reassuring... it has to be an electrical issue. i also disconnected the battery for a minute... the ,abs and esp light still came back on... im at a loss. i fear i may have to take it to the local stealership Monday... cars never given me problems untill this brake job.. and i dont blame the car... or rats

 

When they put the new brakes on did they drill the hole in the pads for the wear sensor, if so then try, or if not this should still work, but a shop should have drilled the hole for the wire
Turn on the car and turn your steering wheel all the way to the left then all the way to the right - then center it. Turn it off then back on again and see if it goes away.
What I did when I put new brakes on.

 

For the bas/esp light

 

http://api.viglink.com/api/click?for...bas_esp_03.gif

 

They basically just told you to take it somewhere else. I'm sure you can find an independent Mercedes shop in your area.

 

i had no idea a hole was needed to be drilled , could this be causing all the issues? and i tried the lock to lock thing, didnt help, i am going to take it to the dealership tomorrow, do you guys think a Mercedes shop would be cheaper than the dealer?

 

I put new pads on and didn't have to drill a hole, the sensor went right back on to the caliper where it was before.

 

So update, just drove the car and the lights went off... could it have just needed time to reset, or do you think the issue is simply dormant for a bit?

 

Some pads have the hole some don't.

 

Mine will have all of those lights on right after a carwash, but they always go away after 3 trips or on/off cycles.