Need ABS Troubleshooting help

[bryangor]

Hi All,

I am trying to troubleshooting an ABS issue on my 2012 Liberty and have not been able to find the exact same symptoms in the other threads I've read through. Here's what's happening...

*ABS/Traction/Service 4w Drive lights are on (sometimes red brake light)
*I have cleared them a number of times, but they return
*Occasionally lights will go out on their own (usually at start up). While they are out the ABS pump will make a shuddering noise (I think the pump, left front?) and brakes will stop poorly... then lights will come on again and car will brake fine (I assume because ABS is no longer kicking in)
*I've replaced both front ABS sensors, but issue remains.

Does anyone know...
*If replacing rear sensors potentially fix this?
*If the shuddering noise points to the pump/module being the issue?
*If I can just disable ABS (and have lights go out and cruise control work again)?

Would appreciate any suggestions. I tried to be as detailed as possible

Thanks, Bryan

 

[John P.]

Hi and welcome. First is your scan tool capable of reading abs? If so what are the codes? I think your module is probably fine. It sounds like you have a bad pig tail or broken wire. I would look for pinch points along the harness that leads to the hubs.

 

[bryangor]

Hi and welcome. First is your scan tool capable of reading abs? If so what are the codes? I think your module is probably fine. It sounds like you have a bad pig tail or broken wire. I would look for pinch points along the harness that leads to the hubs.

Just got a scanner with abs yesterday... C1027 and C102A.

My 1st scan yesterday also showed C2200, But since the warning lights had been on for a while, I decided to clear it and see what came backup after driving a bit

 

[John P.]

Well it's good both front sensors are working properly. Those codes both reference the Left Rear ABS sensor. Possible causes, mis sized or overly worn tire at that position, dirty tone ring, bad sensor, or bad wiring/ground, or connection. More than likely the sensor is fine and you need to chase and test wires. The symptoms you described really make me think wires still, especially having the codes you do. What is happening is the module is reading the signals, you push the brake peddle, the module senses the left rear tire rotation is slower than the other tires or the signal stops and that's interpreted as wheel lock up. It face palms itself thinking *** is this guy doing and it tries to correct the skid. Eventually it decides it's owner isn't dumb, and it must have a problem in it's system so it turns on the error lights and patiently waits for someone smarter than itself to correct the malfunction.

 

[bryangor]

Just got a scanner with abs yesterday... C1027 and C102A.

My 1st scan yesterday also showed C2200, But since the warning lights had been on for a while, I decided to clear it and see what came backup after driving a bit

Well it's good both front sensors are working properly. Those codes both reference the Left Rear ABS sensor. Possible causes, mis sized or overly worn tire at that position, dirty tone ring, bad sensor, or bad wiring/ground, or connection. More than likely the sensor is fine and you need to chase and test wires. The symptoms you described really make me think wires still, especially having the codes you do. What is happening is the module is reading the signals, you push the brake peddle, the module senses the left rear tire rotation is slower than the other tires or the signal stops and that's interpreted as wheel lock up. It face palms itself thinking *** is this guy doing and it tries to correct the skid. Eventually it decides it's owner isn't dumb, and it must have a problem in it's system so it turns on the error lights and patiently waits for someone smarter than itself to correct the malfunction.

Thank you so much John for the detailed explaination! My right rear tire is actually more worn than the left, perhaps that's a contributing factor... hopefully the rain will hold off tonight and I can run through the possible solutions you supplied. I'll be sure to post what I find out. Thanks!!!