abs light on and off, speedomotor erratic

[powersmoked]

I have a 1999 ford ranger 2wd 5 speed manual, 2.5l My abs light comes on sporadically( it will come on stay on for a few days then go off). my speedometer only starts to work when i am going about 15 mph. I had the rear speed sensor replaced and this did not solve the problem. when i put the brakes on a can feel them acting funny. I pulled the fuse for the abs and the light stays on. the speedometer starts to work at about 15 mph and the brakes work fine. I put the fuse back in the abs light is off the speedo works at 15 mph the brakes work fine but when i apply them there is a rapid clicking coming from under the dash above the clutch area. I dont think i have a relay for the abs but i might have a resister and a diode. I pulled them and they look clean. any suggestions would be appreciated

[pawpaw]

I see you don't have any responses, so I'll try to get the ball rolling.

You may have more than one problem.

Read through this post, or thread & see if you think it may fit your symptoms.
Ford Truck Enthusiasts Forums - View Single Post - Possible speed sensor problem Paw Paw please help

The speed-o, abs system, cruise control & auto tranny use the rear speed sensors PID output to the computer, so if the speed sensors output is corrupt, any of the other systems that use it's output may also act up.

Do you have 4WABS & if so, can you tell if it's the front, or rear brakes that are acting up???? If you have the 4 wheel ABS system, also check the front ABS sensors & brake rotor for rust debris, or for cracked, chipped or missing rotor reluctor vanes.

Look in the "Tech Info" thread atop this forum & scroll down to the "brake" listing, for how to pull your ABS trouble codes, then post ALL of the code Numbers.

If you don't want to do that, then consider running this puppy by a brake shop that has a scantool that'll hook up to the diagnostic port & pull the ABS codes, then post ALL of the code Numbers here.

Some thoughts for consideration, let us know what you find.

[powersmoked]

thanks paw paw for responding. I have rear abs. (rabs) the site will not let me update my signature for some reason. as soon as i have a chance i will read the tech about pulling the abs codes and I will check the wire that runs from the vss in the differential and post what i find. thanks

[6 cyl boy]

Pull the vehicle speed sensor on top of the rear differential it is either contaminated with metal shavings or just bad. The part should run about $30 and will fix the abs light and the speedometer issue. as far as ABS codes you cant get them from a scan tool on a 99, their is a connector on the passenger side behind the kick panel. You would pull the connector apart and ground one of the terminals to receive a flash code from the ABS light. Most likely it would tell you no VSS signal is present or the VSS signal voltage is low. The VSS is an AC output sensor both wires going to it are outputs and will give you an AC voltage when the rear wheels are spinning. Don't bother looking for a reference voltage their is none.The sensor it's self should give you a resistance reading when unplugged. If you get no resistance reading or it is very high (kilo ohm mega ohm range) unplugged (OL on most meters is an open circuit) then the sensor is bad and you must replace it.

[powersmoked]

thanks for the input. as i said in the initial post I had the vss on the diff replaced about 8 months ago. I think it corrected the issue for a little while then it started again. I was thinking of just replacing it again. I looked underneath and did not see any obvious damge to the wiring. I did check my diff fluid about 3 months ago and it was down about a quart. could that cause some shavings that would collect on this vss. is the vsss a magnet? the abs light is off now but the issue is still there. speedo starts at 20mph, clcikkng sound from dash when braking. thanks again.

[mfp4073]

Ok, how about this. Sounds like that sensor...but if you replaced it with no change, maybe a wiring issue related to it? isnt there a connector under the drives seat that sometimes gets corroded?

I really dont know what I am talking about....just throwing that out there!

[powersmoked]

Someone had mentioned a box under the drivers seat. I don't have one. I think my abs controller might be behind the kick panal at passangers feet.

[pawpaw]

OK, so the speed sensors wiring looks ok. Did it's electrical connectors contacts also look ok????

Seeing as how you say replacing the rear ABS speed sensor fixed the problem for a while & you've had low differential lube level problems, to the point that the old speed sensor was covered with metal shavings, I agree, the new speed sensor probably belongs on your suspect list again.

I'd first pull the ABS codes & see what they have to say & if the system is unhappy with the speed sensors output, just replace it.

One 10mm fastner, one electrical connector, one "O" ring around the sensors body as a seal, twist & pull & it's out.

Lube the "O" ring on the new sensor, insert the sensor, torque the 10mm fastner to 25-29 ft/lbs, fasten the electrical connector & your finished.

If your slow like me, maybe a 30 min job, if your a speedy wrencher, maybe a 15 min job!!!!

Keep us posted on what you find.

[Rockledge]

Originally Posted by mfp4073

Ok, how about this. Sounds like that sensor...but if you replaced it with no change, maybe a wiring issue related to it? isnt there a connector under the drives seat that sometimes gets corroded?

I have heard that that some late-build '99s are actually wired like the '00 model year, which means they would have a certain harness connector located under the driver's seat area that can be prone to water corrosion problems, as described in this TSB: http://www.ford-trucks.com/forums/sh...92&postcoun=10

[6 cyl boy]

The harness goes through the floor on the 99 but their is no connector. I doubt this is the problem anyway because the harness is pretty well protected by the frame rail underneath. If possible I would raise the rear of the vehicle on jack stands block the front wheels put the truck in drive while running and get a reading from that sensor. Or at least pull the sensor and check it for damage and resistance.

[Rockledge]

Originally Posted by 6 cyl boy

The harness goes through the floor on the 99 but their is no connector.

That's how it is on my '98, and I assumed it was the same for 99s as well. But like I noted, I have heard - or more likely I have read in another forum somewhere - that a few people with '99s actually found a 40-pin connector under the drivers seat, the same one described in the aforementioned TSB. I don't have any personal knowledge of that being true, and I suppose you might call it hearsay, but I think it's something for the OP to at least keep in mind.

I doubt this is the problem anyway because the harness is pretty well protected by the frame rail underneath.

If we are thinking about the same 16-pin connector, then I would argue that it's not as well-protected as you might think:

http://www.ford-trucks.com/forums/31...und-today.html

[powersmoked]

solved. To review I had the vss in the diff replaced about 8 months ago. the issue appeared to have been solved. then the abs would come on for a few days and go off . the speedometer never worked until 20 mph and i would get a clicking sound from under the dash. this morning i pulled the vss in the diff off and cleaned it put it back in nothing changed. I then picked up a new one at the zone for $20 ( I think i bought the last one there also I bought the part and had the mechanic install it) I installed it and it appears to be working the clicking is gone and the speedo and odometer are working. the abs light had not been on. I backed up on to car ramps and used a 10mm for the one bolt and the poped it out it has an oring on it...

thanks for all your help

[pawpaw]

OK, good feedback & to hear your problem seems to have been solved & your "on the road again"!!!!

[mfp4073]

I really hate to be the guy that tries to suggest using the same tool for every job....but its amazing how many problems are solved by that stupid sensor.

[g_k50]

Make a note of mileage so that we can see if the intervals between failure are getting closer or further apart.