Obscure Electrical fault

[ourtomtom]

The vehicle in question is a 2002 Classic 4dr Saloon E200 Kompressor, with only 32,000 miles on the clock genuine. On connecting the battery and starting the engine, I rotate the steering wheel full lock L/R, as indicated in the manual. The ABS & BAS warning lights go out and it shows 1 malfunction - please check lamps. I check all lamps and can find none defective. On depressing the footbrake the ABS & BAS warning lights illuminate and the menu shows 3 defects. By switching off the engine and restarting the ABS & BAS warning lights go out but illuminate again as soo as I touch the footbrake pedal.

Previous advice was to try a new stoplight switch but the fault remains and I'm flummoxed. So I'm looking for further advice & suggestions that help me to avoid the dreaded diag. Any ideas?

A Previous fault with this vehicle turned out to be a defective connection within the engine control system unit connecting plug, it was due to a low voltage supply to the unit. This was eventually traced to a connection inside the plug and rectified by the local dealer at an obscene cost. Symptoms of this previous fault, had been erratic operation of the ABS system that caused the vehicle to slew sideways on RH bends.

Whilst the latest fault I outlined above, occurred shortly after this initial fault had been rectified, it did not affect driving except that the ABS and BAS were no longer operative, nor were the Accel/Decel & Cruise controls, all systems which are are easy to do without, especially if it's due to low voltage to the engine control system unit, which causes the vehicle to slew sideways in RH bends.

I would like to get this vehicle up and running again as it is in pristine condition and an excellent ride, but fault prone and at the mercy of the diag brigade. This an onerous situation to be in and equates to the practice of being held to ransom, for daring to own a vehicle with an operating system that is beyond the pale.

I have owned an operated Mercedes vehicles for over a decade now and it has been a thoroughly frustrating experience. But once I get this vehicle up & running again, I am minded to lobby parliament to make initial diags Free of Charge to all motorists - by law. So at least the fault is identified even if I cannot find a way to fix it myself.

It is fortunate that I do not need to use this vehicle immediately, so I can play the odds to find a solution at my leisure. But why Mercedes need to be so sneaky over this rip-off diag business eludes me. It is grossly unfair and needs to be dealt with. Hoping for some useful advice.
Best regards,
Tom

 

[Uncle Benz]

This sounds like it will be either dead simple or dead complex.

In light of the check lamp error, i would first look at the stop lamp bulbs. You say they are all working, but check both the electrical plugs at the rear lamps for blackening of the earth pins, then remove and examine each bulb. It's not uncommon for the crimp holding the filament to open up, shorting across to the second filament inside the glass envelope. This will give some bizarre errors in my experience.