ABS Issues… Need Help!

[arlodeb]

Hey I just made an account for the forum in order to hopefully get some help with an ABS issue I’m having!
Recently got a 1999 4.0 Ranger 4x4 XLT

I’ve been having an issue with the ABS kicking in on my front left wheel (I have 4 wheel ABS) when I brake. This causes the truck to “lurch” or slide forward when I brake at low speeds of ~10mph or less. This happens every single time, on hard, dry, flat pavement. There is no ABS light on the dash either.

I started by putting in new pads, rotors, and calipers before realizing it was likely ABS causing the issue. I could feel the front left wheel having problems when braking so that’s where I went first. I disconnected the ABS sensor and test drove it and she braked perfectly! With this information (and tell me if I’m wrong) I can assume it’s an ABS issue specifically in the front left.

However, when I replaced the ABS sensor and it didn’t resolve the issue I turned to the tone ring. From my visual inspection I see no missing/broken notches or cracks in the ring or anything of the sort but it was very gunked up and dirty. I used brake cleaner and compressed air as well as a small screwdriver to clean the notches and yet still after cleaning up the tone ring the braking issue persists.
I like to pride myself on being able to work on my vehicles and fix issues but I am lost.

I’ve also noticed a burning smell when I’ve come back from test driving it the last couple of times, I’m not sure I’d this is a serious issue or just a typical result of the ABS malfunction and my new pads/rotors being worn in.

I scanned it for codes with my OBD reader and came up with a number of them, among which were P0500 (VSS system fault) and B1483 (Brake On/Off switch circuit failure). I don’t know if either of these are related to my issue but I ordered a new VSS sensor to replace the old one, that way I can at least clear that code. As for the B1483 I’m not really sure what it means.

If anyone has any information or could help in any way I truly do appreciate your time and input! I know this was a lot of typing and maybe over explaining but I figured the more information I give could help narrow down solutions. Thank you!

 

[Mechrick]

The P0500 is a PCM 'P' code. The ABS module sends vehicle speed info to the PCM. There should be a 'C' code in the ABS module.

Having gotten that out of the way, what you are experiencing is a classic WSS issue where the voltage of the sensor drops below what the ABS module is capable of resolving.

It could be a contaminated reluctor or excessive space between the sensor and reluctor.

It could be a break or high resistance between the sensor and the ABS module.

It could be a failing ABS module (but that's rare).

The way I test these is attach a DVOM to the sensor leads (preferably right at the ABS module, but at the sensor is ok too). Spin the wheel while measuring the A/C voltage of the suspect sensor, then do the same with the opposite wheel. They should equal. If they don't, check the reluctor and harness for issues.

The other code is for the brake lamp switch. Check to make sure your brake lamps work, the ABS taps right in to that same circuit.

 

[Uncle Gump]

I've had this happen to me before.

I suggest connecting a scan tool and monitoring wheel speed sensors while test driving. I bet you will find that at the moment the ABS kicks in... one of your front wheel speed sensors went to zero... indicating the wheel stopped rotating... thus entering the ABS event.

Mine had a bad right sensor... the truck would pull left. This would cause the opposite effect if it were the left sensor.

On my 06... the front wheel speed sensors are intregal to the unit bearing.

 

[Uncle Gump]

I also need to add...

When you disconnected the wheel speed sensor... and brakes worked perfectly... it's simply because you disabled the ABS by disconnecting the sensor.

 

[arlodeb]

The P0500 is a PCM 'P' code. The ABS module sends vehicle speed info to the PCM. There should be a 'C' code in the ABS module.

Having gotten that out of the way, what you are experiencing is a classic WSS issue where the voltage of the sensor drops below what the ABS module is capable of resolving.

It could be a contaminated reluctor or excessive space between the sensor and reluctor.

It could be a break or high resistance between the sensor and the ABS module.

It could be a failing ABS module (but that's rare).

The way I test these is attach a DVOM to the sensor leads (preferably right at the ABS module, but at the sensor is ok too). Spin the wheel while measuring the A/C voltage of the suspect sensor, then do the same with the opposite wheel. They should equal. If they don't, check the reluctor and harness for issues.

The other code is for the brake lamp switch. Check to make sure your brake lamps work, the ABS taps right in to that same circuit.

Hey a little update, I replaced the VSS sensor but the P0500 code is still present, since I cleaned and inspected the tone ring (correct me if I’m wrong but I’m pretty sure that’s just a synonym for reluctor) and didn’t see any cracks or damage I have doubts that’s what’s causing the problem. I scanned for codes again after replacing the VSS sensor and now have a C1155 (Left Front Wheel Speed Sensor Input Circuit Failure) except I already replaced the wheel speed sensor. Any ideas of what’s causing the C1155 despite replacing the WSS? Tomorrow I intend to test the Ac outputs of the sensor as you described, if it doesn’t match up, what should I look for? I’m assuming damage in the wiring harness further up the line? Thank you all for the help it really is appreciated!