2005 Ranger FX4 - started experiencing abs slippage when coming almost to a stop. Have since changed both front ABS sensors but still have same problem. When I unplug the driver's side sensor, ABS dash light stays on but there's no slippage. Is there any way to distinguish which sensor is bad? Any suggestions?

Thanks!

 

Need to hook it to a scan tool that can see what each sensor is doing. One is dropping out at low speeds so it thinks that wheel is locking up.
You can unplug the sensors and hook an AC volt meter to the pins and slowly and consistantly spin the wheel. it shoud output a steady AC voltage. The one thats bad will occasionally drop of 0v output.
The rear wheels use one sensor off the driveshaft i belive at the tail of the trans housing.

 

Thanks for the reply. Does that sensor generate its own voltage? If so, how much should it put out normally? What gets me is that I paid over $200 for the driver's side sensor from the Ford dealer and less than $40 for the other side from an online source. They look identical. How important is cleaning out the cavity where the sensor sits and what's the best way to do it if I need to go back in?

Thanks!

 

Update: I checked for voltage at the plug, as recommended. On the driver's side, I got 0.013- 0.014 volts AC steady while rotating the tire. I got no voltage from the passenger's side plug. I'm not sure if that narrows it down. I don't have a scan tool to check it with. Any recommendations as to where I could borrow one?

Thanks,
Rick

 

Sounds like you found your culprit. Drivers side reading seems OK depending how fast you were spinning it. Pass side should show comparable result when spinning the same speed. I snagged the female end from a junkyard truck so i can plug in the sensor male end , clip my VAC meter on the exposed wires to maintain a good contact, and spin the wheel as steady as i can.

Oscilliscope can also be used to visually see the sine wave if you know of someone with one of those but at this point not necessary.

Where did you get your sensor? I had to replace my pass side sensor as well and bought one on amazon for about $40 and it doesnt work either (behaves the same as the old sensor dropping out at low speeds) and i can see it drop out on my scan tool at less than 5mph. Ive removed the rotor (2wd) and inspected the ring with no issues found, even swapped with the drivers side rotor and the problem stayed on the pass side.

I'm thinking there is a rash of bad sensors...