Najalo

Hey!
I'm having a very strange problem on my CLK.
The ABS, BAS and the ESP lights up on the dash when I've been driving it for 2-3 minutes (nothing lights up on start up)
I've cleaned both of the reluctors in the back and cleaned all the ABS sensors as well.
I bought four new ABS sensors and installed them but the problem wasn't solved so I brought them back to the shop and installed my old ones again.
What happens when the lights appear is that the car goes into limp-mode (locking itself into the gear it's in) if I shut the engine off and start it again the lights goes away but comes back when I'm driving again.
If I take off the two fuses under the hood (5 and 40 amp) the ABS, BAS and ESP lights light up when starting the car but it drives good like it should and I've also changed my brake pads and discs so when removing the fuse the brake pedal takes very good (almost on top like it should be) but if I put the fuses back in the brake pedal vibrates like the ABS is in and it goes down to the mid and there the lights come up, has anyone ever had this problem?

Plutoe

You got a bad control module, find someone with a good tester who can read the system and they will solve your issue---all else more parts and more HS!

Najalo

This is what I got from the diagnostics:

C1200 - brake light switch (I've replaced it twice just to be sure)
C1500 - rpm sensor, plausibility incorr. teeth no.
C1504 - system switched off, steering angle sensor not initialised
No steering angle initialising

what do you mean with module? The ABS pump under the hood?

This happened when I changed my tires in the back from 285/25-20 to 275/30-20

Serndipity

An important issue in the selection of your tires, is to make sure that the rolling circumference of the new set up is not more than a percent or so, different than the OE factory wheel and tire size set up, on both axles.

Reason being, the various sensors provide important inputs to numerous vehicle computers (e.g. transmission, braking, cruise control, electronic stability / traction control programing, not to mention your speed sensitive power steering, radio volume, speedometer/mileage etc.).


Tire size Sidewall Radius Diameter Circumference Revs/Mile Difference
285/25-20 2.8in 12.8in 25.6in 80.5in 788 0.0%
275/30-20 3.2in 13.2in 26.5in 83.2in 761 3.5%

PS: Also, whenever your vehicle battery is disconnected, you have to initialize the steering angle sensor, as described in your owner's manual.

Najalo

So my tires are too big?
I've tested the ABS pump through DAS and it's making noize when opening the hi/lo pressure valve so I guess its working

Plutoe

Wada joke, say nothing in your first post, then after a bunch of nonsensical answers, then you post all the test data.


Your issue is not a control module but miss matched tires--put all the same size tires on the car and live long and prosper

Najalo

Thanks for the response guys, but I wonder one thing.
If I have bigger tires, why didn't this happen when I had 285/25/20?
Got 275/30-20 now so weird how it does now when I have smaller ones

A1EK

comparing your tyre sizes shows an incease in diameter of 3.5% on the 275 x 30" compared to the 285 x 25" which is a slightly above the recomeneded 3% difference. The exact match would be 235 x 30" rather than 275 x 30" However you could probably counter act the difference to see if the ABS BAS ESP lights go out by deflate the 275 x 30" a little to see?

Secondly, I would still think its the brake switch as they are delicate and you must by original Mercedes, OEM will fail from experience.

Serndipity

Do the math!

The factory setup on your CLK320 is 205/15-16.

Your rolling circumference with the 285/25-20 tires was only 2.9% more, while the rolling circumference with the 275/30-20 tires is 6.5% more.