C1211 Rh rear abs sensor sparatic

[Fummins]

I have a 2015 Mirage here with 490k km. It keeps throwing a C1211 code.
From the manual:
DIAGNOSIS CODE SET CONDITIONS

The ABS/Active stability control system-ECU sets diagnosis code No.C1211 when the rear right wheel speed sensor signal is in either of the following conditions.

When the rear right wheel speed sensor signal is significantly different than the other ones.
When the system detects a periodic pulse missing while a gap occurs in the front right wheel speed sensor pulse signals.
When the rear right wheel speed sensor creates an abnormal pulse signal.
PROBABLE CAUSES


Improperly installed rear right wheel speed sensor
Presence of dirt or other foreign particles on the encoder of the rear right wheel speed sensor
Deformed encoder of the rear right wheel speed sensor
Excessive gap between the rear right wheel speed sensor and its encoder
Damaged wiring harness or connector
Malfunction of the rear right wheel speed sensor
Malfunction of the hydraulic unit (integrated with ABS/Active stability control system-ECU)


Thinking out loud and at random here...

It's intermittent. I can monitor wheel speed with the back jacked up, but it seems to loose signal when spinning it constantly. And sometimes it'll just quit reading altogether. I monitored wheel speed on a recent test drive and all was fine for the first few blocks then it read 0kph and wouldn't come back. I replaced the speed sensor twice now. It seems like unplugging and plugging the speed sensor connection sometimes brings the signal back. It's pretty sporadic. I rigged up a drill with a rubber pinstipe removal disc to spin the wheel at a somewhat constant speed while I ran around with the scanner monitoring wheel speed data and wiggling the harness all over the car from the rear under the rear seat, along the rh rocker then along the lf rocker up to the kick panel connector, there's no difference. The drum is relatively new and came with the encoder ring pre-installed.
I'm thinking there's a break in the harness somewhere or maybe on the circuit board for the abs module? I haven't traced wires all the way to the engine bay yet. I've been picking away with this turd for a few days while trying to keep up with everything else. I don't want to kick out until it's fixed.
Next step is to try a different drum and see if maybe the encoder ring is effed. When it is reading at a constant speed the speed will jump up and down like the ring is missing a "tooth" but it's not constant. I guess I should check voltage at the sensor wiring first, I believe it should put out a tiny bit of ac-current when the wheel spins? That'll if the reading is irratic there then it's probably the ring or bearing?

[Fummins]

I ended up replacing the abs ring on the drum. So far so good, I can't get it to screw up now. Before it'd throw a code within 5 mins of driving. Just took it out for 15-20min drive and no lights and it seemed to read speed fine with no hiccups. Fingers crossed it doesn't come back again. Seems to me the light came on shortly after I replaced the rear brakes(drums and shoes).

[Fummins]

Update on this one, 492k km(as of last week). It seems to be fixed. The abs ring that was pre-installed on a new drum(installed at 480k km) was the problem.
It was a pita to figure out cause it was so intermittent and I had no idea there was still a problem until it came in for other work with zero mention of the dash half lit up with warning lights. Most of the time the abs wires break at the front of the trailing axle where they're most exposed to the elements.