Have a 2005 F 150 4X4 - the ABS light will not go off. We have checked the brakes, the shop thinks it is the rear differential speed sensor but we can't find one at any parts places. Is it the same one that was used in the 2004 model?

there is a ABS sensor on the rear differential that also works as a vehicle speed sensor. most likely tkis sensor is causing your concern.

If I remember correctly, the rear differential speed sensor is also the rear ABS sensor. Since the speedometer also needs to know the vehicle speed it seems like this the most likely source of the problem you are describing.

The vehicles rear speed sensor can be read by a scan tool to see if the signal is there or not. It wont be a code, just whether it is sinding the correct signal. Most shops or your dealer should be able to perform this test in about 10 - 15 minutes.

The sensor is located on the top of the rear differential in the center of the pumpkin.

Check for disconnected ABS sensors. The front sensors in the front are located next to the axle shafts. The rear sensor is located on the rear differential housing itself on top, in the middle. The ABS is monitored by the computer for performance. The ABS kicks on when the vehicle comes from a certain speed to a dead stop, keeping the wheels from locking up. That could be the reason for the speedometer not working. Or it could be a bad speed sensor. Both can also trigger the check engine light because it is monitored by the computer. The brake light usually comes on due to low fluid level. It can trigger the light, but not be low enough to impact brake performance. I hope this helps.

sounds like wiring to rear speed sensor in rear differential or speed sensor itself..check wiring and connector to speed sensor..if looks ok..remove sensor and check for any damage to end of sensor..if ok..i would replace sensor..might be able to get aftermarket,if not,dealer part..most likely cause of your problem..i have seen this before..i hope this helps

Hi


To start with check the Speed Sensor on the front and rear. Usually the issue is with the rear speed sensor which can be replaced easily and will cost you around $25-$40. There is a sensor at the top of the rear differential for the ABS system. When the ABS sensor on the diff goes bad the Speedo no longer will work, the odometer stops recording mileage and both brake and ABS light comes on. You also loose O/D or "Lock-up" in the torque converter. The sensor is inexpensive and can be changed in about 30 mins.
Replace rear differential speed sensor as follows:
a) Remove parking brake cable bracket (1/2" socket)
b) Remove speed sensor bolt (9/16" deep socket)
c) Remove metal speed sensor cover
d) Remove speed sensor from rear differential housing (use channel lock pliers, twist gently back and forth while applying upward pressure. Once the speed sensor has a small gap between it and the rear differential housing, insert a flat-blade screwdriver and gently apply upward pressure while gently twisting speed sensor back and forth.
e) Disconnect speed sensor from speed sensor cable
f) Lubricate new sensor with WD-40, insert into rear differential housing. It will NOT go in all the way by hand, so do NOT force it nor hit it with anything made out of metal.
g) Replace metal speed sensor cover
h) Insert speed sensor bolt and tighten LIGHTLY until a small amount of pressure is felt. Tap speed sensor with rubber hammer until it pops into housing. Finish tightening of speed sensor bolt.
i) Replace brake cable bracket, replace 1/2" nut and tighten
j) Disconnect positive battery cable for 2 minutes, reconnect positive battery cable

Please do accept the solution if the issue is resolved or else revert for further assistance.


Thanks
Rylee

From what I have read this sounds like a problem with the second speed sensor located on back at the rear axel on top of the differential. If the cable is loose or the sensor is bad it will cause the brake light to come on and the speedometer to act funny. There are two speed sensors...one in the transmission and the one on the differential. The second one is probably the problem.

There is a sensor at the top of the rear differential for the ABS system. That sensor went bad and replacing it took care of the problem. What caused mine to go bad was apperantly water got into the differential when launching and loading my boat. check to see if gear lube needs to be replaced also.
The answer above is perfectly correct. When the ABS sensor on the diff goes bad the speedo no longer will work, the odometer stops recording mileage and both brake and ABS light comes on. You also loose O/D or "Lock-up" in the torque converter. The sensor is inexpensive and can be changed in about 30 mins. Good Luck!
I second the second answer :) My ABS light was on, my BRAKE light was on, my CHECK ENGINE light was on, my SPEEDOMETER wouldn't work below 35 mph, then quit working alltogether. Once the speedomenter quit working the odometer and cruise control quit working. I replaced the rear differential mounted speed sensor ($33) and then reset the CHECK ENGINE light by disconnecting the positive battery cable for a couple of minutes. EVERYTHING then worked.
Replace rear differential speed sensor as follows:
a) remove parking brake cable bracket (1/2" socket)
b) remove speed sensor bolt (9/16" deep socket)
c) remove metal speed sensor cover
d) remove speed sensor from rear differential housing (use channel lock pliers, twist gently back and forth while applying upward pressure. Once the speed sensor has a small gap between it and the rear differential housing, insert a flat-blade screwdriver and gently apply upward pressure while gently twisting speed sensor back and forth.
e) disconnect speed sensor from speed sensor cable
f) lubricate new sensor with WD-40, insert into rear differential housing. It will NOT go in all the way by hand, so do NOT force it nor hit it with anything made out of metal.
g) replace metal speed sensor cover
h) Insert speed sensor bolt and tighten LIGHTLY until a small amout of pressure is felt. Tap speed sensor with rubber hammer until it pops into housing. Finish tightening of speed sensor bolt.
i) replace brake cable bracket, replace 1/2" nut and tighten
j) disconnect positive battery cable for 2 minutes, reconnect positive battery cable
h) start vehicle, enjoy,

1. Check the resistance of the rear wheel speed sensor. It should be 1200-2500 ohms.

2. If OK, check the wiring between the rear wheel speed sensor and the Controller Anti-lock Brakes (CAB

sometimes this sensor is on the rear of the transmission or the rear differential.

sensor in rear diff may need replaced

Speed sensor located in top of rear diff is probably bad, It sends a signal to abs module for abs, it also is used by pcm and cluster for vehicle speed.Sometimes rear diff mechanical problem can damage the sensor. Trans sensors have nothing to do with speedo or abs light.