W124 400E Cant fix ABS issue, Help!

[Sammy92]

Hello,

I have been struggling for 2 years now with 400e 1992
Abs issue.

Abs light comes on when i exceed 50kmh,
sometimes very quickly sometimes after some minutes.
Cruise wont work also.
My car is non Asr version.

Home made blink code reader gives from pin 6 (abs)
16 flashes (Vehicle speed sensors (L6, L6/1, L6/2), implausible signal)

I have changed ALL abs sensors one by one to new oem.

Before i changed front right sensor, i got sometimes also 3 flashes (front right abs sensor) from the Pin 6.

List of what ive done so far:

- All new abs sensors(3)
-New brake light switch
-Changed Abs pump relays (used parts)
-Changed Abs module (used)
-Measured abs wires from the sensors connectors
to the abs module with multimeter that the wire are okay
-Checked abs pump electric motor, okay
-Something that i cant even remember

Still nothing has chainged.

I have changed my rear diff from original 2.24 to w140
3.5td 2.82 and changed the abs ring from the old
Pinion, due to info that ive found on here.
But the issue was before this diff change.

ANY ideas?

Could be that both off my Abs modules are bad?
Only thing left that i can figure out is that i measure
Abs module capacitors if theyre gone bad and if so
Change them. (Ive fixed this cars T/LLR and LH by changing those dead capacitors).

 

[gsxr]

Do you have the same size tire front & rear? If not, that would cause a problem.

The toothed ring on the pinion needs to match the gearset, so you don't want a 2.24 ring with 2.82 gears... hope that is not what you did. The 2.24 ring should have 43 teeth, the 2.82 gear should have 34 teeth.

The easy test here is to connect Star diagnostics (SDS) and run HHT-Win to display live data from the ABS computer. It will show you the exact speeds from each front wheel, and the rear wheels. That will tell you which one(s) are reading incorrectly. If you don't have SDS, see if you can find someone locally that can let you use one for a half-hour. All you need to do is drive for 5 minutes at different speeds while a passenger watches the speed readouts on the screen.

 

[a777fan]

Have you confirmed that all wiring from the affected sensors is intact and functional while driving? There may be a short which only rears its head when the suspension and car are moving relative to one another...

 

[samiam44]

How's the wiring to the sensors look? I've seen them break up.

I think Dave hit the nail with the hammer. If you've put a 2.24 input onto a 2.82 gear, then the rear sensor is reading way different than the front 2 wheels. You could check that with HHT or you can uses a multimeter with a O-scope. Turn the wheel with a certain RPM and look at the signal. You can go up to the box. Then do the same with the other wheels.

The ABS can module- you could exchange with another, but I'd replace fuses in the BM.

I've seen a few 2.82 conversions and they usually just use a converter box.

Michael