ABS/WSS Failure. Anyone have wiring path info?

[CorneliusRox]

I got a nice ABS/Brake/Service 4WD brigade of lights on my dash the other day. No codes. Brakes, ABS, and 4WD still work as intended, so I figured it had to be a wheel speed sensor. I ordered up both fronts and the rear diff sensors (>200k on the truck and parts were cheap). I swapped them out and the lights still come on intermittently.
My best guess is it's a short in the harness somewhere since I now know the sensors are good and the connectors all looked great.

Does anyone know the wiring path for these so I can start with continuity checks, and then start pulling tape off harnesses? Or know of a common issue driving this on a 2010 truck?

I leave on a long trip Friday and would love to have my cruise control back for it!

[CorneliusRox]

Well, no issues on the drive out. Then nothing but lights on the way back. My best guess is the cold weather froze something somewhere.

I'll update if I figure it out.

[CorneliusRox]

I picked up AlfaOBD (pretty cool software if anyone doesn't know).

I was able to talk to modules individually and see it says an incomplete circuit on the rear wheel speed sensor.

I also was able to relearn the TIPM, and clear every code from every module. Some of the passive codes were due to things like me switching my fog lights to LED bulbs and there was an option to take note of that. The only thing is I can't seem to connect to my TCM.

Anyways, my sensor is brand new and looks great, so I'm thinking there's a bad pin/cut wire somewhere. Worse case I'll run a set of wires outside the harness all the way to the front. If anyone has a schematic for where those wires tie in, I'd appreciate it! I'm guessing they go directly to the ABS module, just not sure on the pins.

Thanks!

[BigPapa]

What truck are you working on?

[CorneliusRox]

Originally Posted by BigPapa

What truck are you working on?

My 2010 4WD Crew Cab, 6.6' box.

[BigPapa]

[CorneliusRox]

Well... I think I made some progress.

Part 1:
-I took the rear wheel speed sensor off (ABS Sensor), and it ohmed out at ~3MOhm, which seems a little high for a WSS, but it's not an open or short so it's probably good?
-Anyways, I cleaned it, checked the wires, cleaned the connector, tossed some dielectric grease in there, and put it all back together.
-I started the truck and the problem wasn't solved.

Part 2:
-I chased the harness to the front and didn't see anything suspicious.
-I didn't have a long enough wire lying around to do a continuity test from the ABS module to the sensor at the rear unfortunately.
-The connector at the ABS module looked good/clean on the inside, but pretty muddy on the outside. Probably a product of my dirt road.
-I popped the connecter apart and cleaned it with some brake clean. The pins looked good.
-Tossed it all back together
-No more lights. It all seemed to work. Went for a drive, all was good.

Part 3:
-I went through a car wash and when I left the wash and took a right hand turn, the lights intermittently came on. My speedo also was jumping around.
-Then the lights finally stayed on and the speedo went back to normal.
-I checked connection to the ABS module vis AlfaOBD and there was no communication.
-I checked communication again after 20min of driving and it was back.
-I pulled over, pulled the connecter, there was some water, I cleaned it best i could with a rag, put it back together, and cleared the codes.
-Everything was good after that. Drove about an hour with some starts and stops. No issues at all.

Part 4:
-This morning it was 16deg. All my lights were on. I didn't have time to do any diagnostics.

My best guess is this is an issue with water intrusion at the ABS module. I think I'm going to let everything thaw and dry/evaporate at the ABS module without the plug in, then pack it with some dielectric grease and see if that helps.
What's anyone else think?

Alternatively, it could be a water freezing issue in the sensor.
It could also be a wire broken behind the insulation in the harness, but I think that's unlikely.

[CorneliusRox]

Well, sprayed with brake cleaner, then left a construction light on the ABS module for a couple hours with the connector disconnected. I then tossed dielectric grease on it all (even the back of the connector around the seals). Then hooked the batteries back up and cleared all codes.

No luck.

I did graph/log the rear wheel speed sensor and went along the harness shaking it waiting for a blip in connectivity. Nothing.

I'll try and get a wire long enough to test conductivity next.

Possibly the new WSS is just faulty? I'll probably order a new one up if I still don't get anywhere with the conductivity test.

[BigPapa]

What codes are you getting?

[CorneliusRox]

Originally Posted by BigPapa

What codes are you getting?

C1036 from the ABS Module
"Rear Wheel Speed Sensor Circuit - Error present"
Power Supply Voltage: 8 V
Rear right wheel speed: 255 km/h
Rear left wheel speed: 255 km/h

[CorneliusRox]

Solved the issue FINALLY.

First off, Scott, Thank you for all the help. I really appreciate it.

Secondly, the issue ended up being the connector for the rear WSS that sits on the top of the diff. It got water in it, when it got cold, it froze and broke the pin in half. This made it so I still got a voltage signal of 4V (not 12V), intermittent connection (sensor working), and really threw me off.

Parts used to fix it:
Aokus ABS Wheel Speed Sensor Connector Pigtail for DODGE DAKOTA DURANGO RAM PICKUP VOLVO & More ($12.99)

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Standard Motor Products ALS258 Wheel Speed Sensor ($13.17)

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Then I packed the sensor with grease to the point that it pushed out the back of the seals when the connector was put on. This should buy me more than another 200k hopefully!

Story time:
I ended up going through this whole freaking system. Dropped the fuel tank so I could completely trace the harness. I hate having a chopped up harness on anything so I was trying to avoid that. Took the ABS module out, tested a bunch on the PCB, let it sit by my wood burning stove for a couple days to dry, reinstalled with lubricated seals, super clean. Checked TIPM for bad solder joints, nothing wrong there that I could see. Bought some wire so I could do voltage and continuity testing the whole length of the harness. Found I had 12V all the way to the connector, but not after the pin. So... finally I bought the connector pigtail, got it hooked up, good as new.
I just LOVE these electrical issues. I am surprised this happened though. I would have figured a sealed OEM connector wouldn't ever take on water, but then again, they don't test to 10years/200,000miles.

Thanks again Scott!

[BigPapa]

Any time, sir. Happy to help.