Speedometer Still Out...

Psycho Mythic

Psycho Mythic

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In PCB my speedometer went out, an the abs and brake light and engine light stay on. I ordered and changed my abs/speed sensor on te rear end but that didn't fix anything. Now what?

I know there's a speed sensor somewhere on the tranny, could that be it? Can it be changed without dropping the tranny? Is it a wiring problem?

Also, even though the check engine light is on it's not throwing any codes...
 
The trim randomly wants tongue off t when I'm coming out of gear, it'll idle fine bit it just shits off sometimes when rolling up to a red-light...this makes me think there's a sensor bad somewhere...
 
If I remember right, all the cluster signals go through the PCM. I would get the PCM reflashed and/or check the connectors for corrosion and being on tight


There is also a cluster test, if I remember right, hold down the trip button for 10 seconds or so and the cluster will cycle all the gauges and lights
 
Rear speed sensor controls the speedo. If you changed it, it might be a short on the wire from the sensor. I have same problem but my ABS kicks in still but my speedo works now after swapping sensor.

Dragon said this: If you know the sensor is good then the other common issue with the 9 1/4 rear axles are the carriers go out and in turn cause the tone ring not to line up with the sensor. I would look more to the rear axle then the front sensors. I have also seen trucks with performance exhaust melt the wiring going to the rear sensor.

The carrier has a bearing on each side of it and the axle shafts go in to the sides. On the side of it there is a metal ring pressed on that has notches in it that the sensor reads the magnetic pulse from as the axle spins. If the bearings on the carrier go bad then it can shift to the side. Typically it shifts towards the passenger side which causes the ring to not be aligned with the sensor causing it not to pick up the pulse.


Thats the best way I can explain it. Hope its good enough lol

Thanks John
 
First thing I would do is check all the fuses.:)
 
Get a scanner if you can plug it in go to the vehicle speed if your getting a signal on the scanner then your cluster is bad. Uf there is no signal from the speed sensor the. The cluster is bad. Now I was looking at alldata and it didn't specify a speed sensor location I would think it should be either on the back of the trans some did the diff sensor I can check my truck later.
 
doesnt sound like the cluster is bad. if you have a check engine light on and an abs light on, there are codes in the PCM and in the ABS module. you need to start there. You need access to a StarScan. it sounds like a. you either got a bad sensor or b. you have a wiring issue from that sensor. Let me also ask did the old sensor have any metal shavings on the magnetic part?
 
My trucks been doing it for a couple months. The speedometer starts sputtering at 75~80 and then the abs brake will go on. I have 2 pcm's and both do the same thing and I also did the brakes rotors and pads.

Let me know when you figure it out.
 
What's the best Way to check to see if this is the problem?

TREKER said:
Rear speed sensor controls the speedo. If you changed it, it might be a short on the wire from the sensor. I have same problem but my ABS kicks in still but my speedo works now after swapping sensor.

Dragon said this: If you know the sensor is good then the other common issue with the 9 1/4 rear axles are the carriers go out and in turn cause the tone ring not to line up with the sensor. I would look more to the rear axle then the front sensors. I have also seen trucks with performance exhaust melt the wiring going to the rear sensor.

The carrier has a bearing on each side of it and the axle shafts go in to the sides. On the side of it there is a metal ring pressed on that has notches in it that the sensor reads the magnetic pulse from as the axle spins. If the bearings on the carrier go bad then it can shift to the side. Typically it shifts towards the passenger side which causes the ring to not be aligned with the sensor causing it not to pick up the pulse.


Thats the best way I can explain it. Hope its good enough lol

Thanks John
Click to expand...
 
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Pull the rear brakes and rear cover, push in and out on the axles and measure the axle end play. If bad you won't have to measure, the axles will move way to much in and out.

With the cover off pry the carrier back and forth , check for carrier side play.
 
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