W203 - ESP/BAS/ ABS error - Need help diagnosing

[Hustler]

Hi guys,

I've had an ESP / BAS /ABS Visit Workshop error on my dash for the last 4 years. Vehicle: W203 - 2003 C200 Coupe, 1.8L Kompressor, manual.

History:
A couple of years ago, I stripped the rear boot flooring material and discovered that there was dampness and corrosion where the wheel speed sensors connect to the yaw-rate sensor. I dried it all up, fully cleaned the contacts and replaced one of the wheel speed sensors but that still didn't fix the issue. Eventually, I replaced the yaw-rate sensor because that was also corroded underneath and voila the ESP/BAS/ABS errors had gone and all seemed well.

Now:

However, that only lasted a year before I got the same errors on my dash. Today, I thought I'd replace the yaw-rate sensor again with one from the breakers as before, but this time it didn't seem to do the trick, leading me to think there's some other issue or that the yaw-rate sensor I bought was a dud.

I did a scan and the following 3 error codes appear:

P202A-001
CAN message from control module Traction systems, Vehicle speed signal IMPLAUSIBLE[P0500]

P202A-016
The left rear wheel rpm signal sent from the traction system via the CAN bus is implausible.

P202A-032
The right rear wheel rpm signal sent from the traction system via the CAN bus is implausible.

Possible related issue?:

Sometimes when I turn the key to start the engine, it ticks and all electrics to the vehicle instantly completely cut out (as though the battery had been completely disconnected) - no electrics at all. I have to disconnect the battery terminal and re-connect it and the car starts fine. Definitely not an issue with the battery itself as the battery is brand new. I'm starting to think that these are both related, but can't say for sure.


Would appreciate any help on fixing the ESP/BAS/ABS issue.

Thank you!

 

[om613]

Brake light switch been replaced?

 

[Hustler]

Brake light switch been replaced?

Yeh, I checked that years ago but there's no brake light switch on mines. Apparently it's only on automatics?

 

[umblecumbuz]

That seems odd. There must be a brake light switch, because not only does it operate the brake lights, it is also interconnected with the ABS system. If the switch does not work, the ABS will malfunction and you'll get the error you have described.

I believe its position was changed (fitted to brake servo, not pedal) during the life of the C class, but not until the facelift version, which I think was after yours, c 2004.