Help to diagnose ABS issue

I have a 2006 4x4 Tacoma that I have been chasing an ABS issue with that I am struggling to chase down. The abs light and park brake light woud come on intermittently until it stayed on permanently.

I got the code C0215 Rear LH Speed Sensor Circuit, C1239 Foreign Object Attached on tip of sensor. The sensor was caked in crap when I removed it so I ended up replacing the axle seal and sensor but the light came back on. There was a tiny bit of play in the wheel bearing but otherwise in good shape.

Inspecting the rear harness they look absolutely fine from what I can see from the harness to the sensor.

I managed to pick up a very cheap ABS module that matched my one so swapped the ECM. Started it up and the warning lights disappeared, great! Then drove two minutes down the road and lights back on with the C0215 code.

So now I guess the best thing to do would be to test the circuit and the module.

I am just struggling to figure out how to do that and would love any advice on the best way to do it with a multi meter?

 

I found this file with a diagnostic process although I cant figure out exactly how to do the resistance test.

In section 7 from what I can tell it says S1-6(RL-) - S22-1(RL-) Am I right in thinking I need to somehow extend the multi meter terminals to reach from the ECU connector under the hood, to the rear sensor harness by the wheel?

Any help would be greatly appreciated!

 

This could be very difficult to diagnose without a good oscilloscope to look at the signal with.

Will your scan tool read the ABS data so you can graph wheel speed and direction to see what's going on?

I'm assuming you checked the wires thoroughly at the connector to the rear sensors? I know they like to break there.

 

Yeah I checked the wires visually and they all seem fine. No damage to the sheathing or obvious damage.

I would have to check whether the scan tool can see live data, I think it could possibly have that option. What kind of thing would I be looking for to diagnose the issue if I can read that data?

 

When I get a vehicle in for an ABS speed sensor fault I'm gona go on a test drive while graphing the wheel speeds on a scan tool, look for glitches or dropouts in any of the signals and note when they occur. Say if they occur when you hit a bump or make a turn I'd be looking for a wiring issue, if they occur in a consistent pattern I'd be looking more towards an issue with the tone wheel.

Toyota gives you quite a bit of data on the sensors including wheel speed, wheel direction, and circuit status.

 

Ok great thanks.

Am I right in thinking the tone wheel is attached to the axle? So the little bit of play in the bearing wouldn't affect the sensor reading?

 

I'm pretty sure the tone wheel is part of the bearing, I know there have been instances of the bearings getting installed on the wrong side and causing ABS issues due to the direction of rotation being incorrect.

 

I pulled apart the rear harness and checked there was continuity through it. I also did checked the voltage to the harness and then to the terminal that connects to the sensor. I had 11 volts so I assume thats ok.

Sound like the play in the bearing could the culprit if it could be affecting the tone ring. It seems that the bearing could do with being replaced so that will be my next step.

 

Did you check if you can look at ABS data with your scan tool?

If you do end up doing the bearing make sure you have someone with the press and tools lined up that can press it off and press the new one on.

Also make sure you get the correct one as there's a left (driver's side) and right (passenger side).

Doorman makes complete assemblies now so that is an option as well but I don't know what kind of quality they are.