ABS issues and intermittent loss of speedo

[Pinball-Mark]

Hello, been having issues with my ABS system. First noticed a problem when my wheels locked up on a rainy day. I have no ABS light coming on, but found out that the light is not coming on at all when I do the key on test. I cant get any ABS codes since the light is not working. Pulled some codes from the system:
PCM p0500 VSS sensor circuit fault

I have had the speedo die once on me while driving but started working again after a cycle of the key. Does any one have any input on the dead ABS light? I have felt the ABS work randomly when turning into my gravel driveway but not when on a wet road. I am leaning toward a bad ABS module since my speedo has died and I would assume if that is happening its either to module or all the wheel sensors have gone bad. I am going to check the speed sensors on the hubs but any input would be helpful. Thanks

 

[SM105K]

I had the same thing happen to me in a 97 Ford Ranger. The speedo sensor in the rear end was the issue, and that made the whole system erratic. I am not by means versed in the Gen 3 platform as I am in the Gen 4/5 platform, however Ford did do things the same across different models. I agree with your diagnosis based on my experience.

 

[99sho-time]

When I put a junkyard abs module in, the ABS light wouldntc ome on when i turned the key that module was stone cold dead worse than the one i took out.

 

[gamefanatic]

Shosource typically has good pulls in stock. Obviously at a greater cost than a straight pull, but they do a good job of checking them and getting you the right part.

Once you get your pump there is a procedure you may need to run to ensure no air is in the system. You can take it to a shop and have them run the test, but I believe the FORscan tool and appropriate OBD-II adapter will enable you to complete the procedure.

 

[Pinball-Mark]

So just to be clear, the module and the pump are one unit?

I have a couple dash lights that don't work either (high beams indicator doesn't come on nor the brake light) which is odd. Might have some electrical issues or burnt out light so I might bull the cluster here first. Thanks for the ideas!

 

[99sho-time]

they are 2 pieces. When I put in my new abs/pump i made sure to split them (can be a hard task) in my case i had to drill the bigger bolt out once i did that i put new bolts with anti seize . because in my opinion its much more common to install a bad module with a good pump. I like to have it set it up to where I change out just module in the car.

 

[Pinball-Mark]

99sho-time. I just found you massive discussion on your ABS issues. For whatever reason i never found it when searching the past 10 times. Anyway, what scan tool were you using to connect to the module. Will forscan connect to module and pull codes?

 

[99sho-time]

forscan should if it cannot connect to the module that means the module is dead

 

[GEN 3 SHO FAN]

Scan is a good idea.

However, that "VSS sensor circuit fault" code could be also caused by wrong signals coming from the wheels. Some resolved this kind of prob by only cleaning their ABS sensors and ABS jagged wheels. Lot of dirt goes there and can false the signal of the sensors.

A rock can also damage one of the ABS wire and that's it. As you're in Ontario, there is also salt and calcium on roads like here.

 

[Pinball-Mark]

Forscan does not seem to see the module, Id assume it would pop up as a module? See pic below. I have gotten to the module and have cleaned the connector. Tested the dash light also by back probing the indicator wire at the connector to ground, light illuminates. The light also illuminated with the connector disconnected from module. I also tested the Hot wires and 12v on all 3. Checked the 2 grounds and all good there too. I guess next step is to test the ABS out again on a gravel road. I also found the emergency brake switch was dirty, cleaned and now it illuminates with the emerg. brake on. But still, the ABS and Brake light DO NOT illuminate when the key is first turned on.. So like you said, i'm probably looking at a dead module. Anyone know if there is any diagnostic flow charts to test the module? Thanks guys

 

[gamefanatic]

I've never had a dead module yet, so have to assume the root issue is the module is dead if you aren't seeing it there.

 

[99sho-time]

Maybe saying a dead module is a little bit to literal. they break in a few diff ways.

So if you unplug an abs module the car wilnot shift out of 1st gear yet at the same time on my old module I had no abs light on startup , no antilock brakes and no ability to check abs codes it would just sat connection error. but would shift. it also had a lilttle bit to do with comfort of the shifts.

I installled a module from the junkyard that had no broken fine wire conections so i assumed it was good that wasnt the case. the original module would play games saying one wheel sensor was bad id change it would say another wheel sensor was bad. when I inspected that one it had quite a few fine wire connections broken.

No abs light with key on just change that module theresno use wasting time.

 

[Pinball-Mark]

Yea i just want to be sure its the module. It sure sounds like it is, but like you are saying a dead module still seems to work in parts. Your issues, 99sho-time were resolved with a 3rd module that was not faulty?

 

[99sho-time]

yes the first try was the junkyard when i slid 50 feet on a damp day i knew it was bad 2nd try was a module from someone on here been holding strong for a long time now.

 

[Pinball-Mark]

Just an update on this. I got a used ABS module from a junk yard down south. I have it installed and the abs is working now. So problem is solved.