P0501 (VSS issue) and a possible ABS malfunction?

[JunkyardDog]

I have a 2011 Jeep Liberty with 2 wheel drive and a 3.7L engine. It was bought used and has a P0501 code and an ABS indicator light. I am electrically inclined and have tools. But, I don't have access to a schematic. I do have a code reader dongle and use Torque.

All of the threads I find about the P0501 involve a sensor on the differential. However, I don't find a sensor on the differential. Can someone shed light on where it is supposed to be?

How can I determine which wheel is causing the ABS issue. Torque is not exposing any codes or other ABS issues.

If I could find out what kind of voltages I should expect, I could narrow down more. I did pull one wheel off and see no voltages. All fuses for ABS are active (has 12V). One of the fuses is only active when entered into Drive (at least it is active). But I see nothing at the wheel.

I could also test the sensor externally, with known voltages to test with (I don't want to apply 12V if it runs on 5V). It is a 2 wire sensor. I assume it is voltage in and pulse out).

Money and time is tight right now and I'd like to be sure what parts to get the first time. Any help is appreciated.

 

[Drag Line]

I’m pretty sure all of the ABS sensors are mounted on the frame.
Above & forward of the rear axle behind the wheel well splash shields.
Above & forward of the front axle behind the wheel well splash shields.
The left rear sensor is black, ~ 2” long x 1” wide x 1/2” thick with 3 wires red & green stripe, a smaller gauge white & a black on the 2011KK.
Hope this helps.

 

[KJowner]

The later Jeep have a sensor in each hub, the early ones only have one rear sensor on the diff.

 

[JunkyardDog]

The later Jeep have a sensor in each hub, the early ones only have one rear sensor on the diff.

Can you define early and late? I have a 2011.

The only sensor I find in the hub are for the ABS. Are the sensors doing double duty?

 

[KJowner]

Late is 07 on, the sensors will be in your hubs. A good code reader will tell you which one is at fault, Torque is only an engine code reader. The code you have is for a mismatch of data from the sensors but doesn't give any further details. I believe the sensors are hall effect so unless you have a scope to look at the output I doubt you will be able to test them.

 

[JunkyardDog]

Late is 07 on, the sensors will be in your hubs. A good code reader will tell you which one is at fault, Torque is only an engine code reader. The code you have is for a mismatch of data from the sensors but doesn't give any further details. I believe the sensors are hall effect so unless you have a scope to look at the output I doubt you will be able to test them.

I have a Bluetooth dongle. Rev 2.0, if that makes any sense to you. Would you know if the limitation to read the ABS stuff is in the dongle or in Torque? If it is in Torque, can you suggest an app that can read the ABS stuff (an app that is reasonably priced for a individual)?

As for the troubleshooting, I do have an oscilloscope. I just don't have a schematic to trace this down (I originally stated this). I know the module is by the battery. It would be nice to know which wires to correctly probe.

 

[klc]

A lot of those dongles don’t do ABS stuff. I had to find a more expensive handheld scanner.

 

[JunkyardDog]

Ca

A lot of those dongles don’t do ABS stuff. I had to find a more expensive handheld scanner.

Can you provide a brand and model?

 

[JunkyardDog]

While looking for a manual, I found a review of the Haynes repair manual on AutoZone that stated that the schematic only covers up to 2004.

 

[klc]

I bought a Foxwell NT716 a couple of years ago, I think their current model is NT614E.

 

[KJowner]

I borrow a mates Snapon diagnostics scanner, I haven't used a Bluetooth one so I can't help there.
If you have a scope then start at the sensors, see if they are working, without a wiring diagram you will have to work back from there belling out the wires. Sensors are the usual culprit though.