Yes its the same DTC Code but now only the one and not 3 wheel speed sensors failure.
C0041 and C0046 and service brake system is gone.

I will check now the Ohm (resistance) of the sensor and the cable if broken points.
last time i checked the connection from the cable tree and the connection with the multimeter and it beeps

 

There are quite a few YT videos on testing wheel sensors.

Indeed just the one wheel however the details given were generic.

Attached diagram may be useful.

 

I took the cable from the right real wheel sensor and put it in the left one.
error is still C0050 but i took a drive and only the front sensors shows the speed on tech2.

possible that the cable is broken?

 

Both rear sensors not working makes sense if you couldn't plug the left cable into the right wheel.

Attached is the GM diagnostic procedure which is very informative.

In essence:-

1. The rear wheel sensors have a resistance of 4500ꭥ to 5400ꭥ (different from front sensors)
2. Unplug the right rear wheel sensor and record it's resistance for reference.
3. Plug it back in and measure it's resistance at EBCM connector pins 1 & 2 (check these) this should be close to the above within 1%.
4. With the meter still connected, go along the harness flexing it and the sensor connector, the resistance should barely change.
5. Again with the meter connected, set it to AC Volts, spin the wheel and check the voltage is aprox 100mV

Perform the same tests on the left wheel sensor for comparison (Pins 22&23) they should produce similar results

The only other thing I seem to recall an EBCM generating random DTC's because the brakes were not not been bled properly, not certain about but it's worth noting.

 

so after weeks of lot of work, it was possible to plug with an extended cable the rear left sensor cable to the right sensor and otherwise.

and still dtc code C0050 right rear wheel sensor circuit malfunction.
then in my opinion the cable would be defective so I checked the continuity with the multimeter with the beep tone and it beeps.

Now I really don't know what to do anymore…

any idea?

For all who want to know how a good ABS Module looks like from inside:

It didn't give me any rest, then I opened the new module to make sure that something hadn't burnt out after all. And it looks perfect!

 

After a few thoughts, I decided to cut off the entire wiring harness at the EBCM module connector and connect the new one with a plugs. Of course, everything will be 100% sealed with heat-shrinkable sleeves and insulating tape.
But what I have noticed is that the old ground cable is black, see pictures. is that possible that this is the problem of my C0050?

New plug:
If you look the ground cable is clean and looks very well


Battery Positive Voltage cables & Ground:
Look at the ground cable. the wires are black

 

Call me Dr. H2 :-D
After I have wired the new plug and secured it with heat-shrink tubing, the error is gone! no more ABS error code. now I will make everything watertight tomorrow with the insulating tape and will take a drive.

newly connected plug

No ABS Error code

Old Plug

 

@George W
That's good work and your findings pretty much explain everything.

The discolored "oxidized" copper strands are typical of wiring that's been exposed to the elements, corrosion can invade way down a cable and can prove difficult to re-connect to. Soldering is tricky often requiring individual strands to be "scrapped" or filed in order to remove the blackened surface.

Food for thought, you've done a lot of work, however imagine the cabling being submersed in water from time to time which given the connector's location is likely.

• The preferred option would have been to replace the individual Delphi terminals, although time consuming, needing crimp tools and correct pins etc, it does solve the problem of ingress protection being the reason its use here (however not now an easy option)
• Next would be to solder the wires rather than use connectors, push-fit terminals can shake loose over time and are not sealed.
• Although normal heatshrink will hold the connectors in-place it doesn't form a water-tight seal around the joints, the same is true of electrical tape. Adhesive lined heatshrink is available which melts around the wires to improve sealing, it's not perfect but would be an improvement.

Having said all this, what you have done may well suffice and will work, the only question will be for how long.

The other question is the root cause for the original failure, it looks like the connector failed for some reason.

 

Thank you for your tips. soldering would be the best solution and It will be done when I have more time. for the moment it works.

The root can be that water was leaked inside the plug and did some short cirquit or something went wrong when the pre-owner changed the brake lines.
Perhaps the pre-owner did something on the ABS Module, when the battery was connected... I don't know

 

@George W
TBH you've stuck with it whereas many would have folded, plus you've kept the forum posted which helps provide a track for others to follow.

Truly great work ✅