Speedo issues, abs light... speed sensor?

[KaZo]

hi, another problem I'm having with my new-to-me '94 C2500. the speedometer doesn't register anything until freeway speeds, where it is pretty accurate 50-70. I notice when I let off or get on the throttle, the speedo needle rises or falls 5mph or so.

at the same time,I get an abs light shortly into my trip that stays on until I shut the truck down. I can feel the rest brakes dumping and re engaging and that makes showing down very disconcerting. the light doesn't stay on next time I start it. I don't have a scanner and the paperclip jumper doesn't get me a code, which makes me think code 9 ( speed sensor erratic). does this sound right? how to fix this problem? any insight is appreciated.

 

[bow61509]

hi, another problem I'm having with my new-to-me '94 C2500. the speedometer doesn't register anything until freeway speeds, where it is pretty accurate 50-70. I notice when I let off or get on the throttle, the speedo needle rises or falls 5mph or so.

at the same time,I get an abs light shortly into my trip that stays on until I shut the truck down. I can feel the rest brakes dumping and re engaging and that makes showing down very disconcerting. the light doesn't stay on next time I start it. I don't have a scanner and the paperclip jumper doesn't get me a code, which makes me think code 9 ( speed sensor erratic). does this sound right? how to fix this problem? any insight is appreciated.

Im not sure on a 94 but on my 96 the vss (vehicle speed sensor) went out one time and it did the exact same things yours is doing. But like I said mine was a 96 and it had a nv4500 transmission, that being said though I would bet your problem is also related to whatever type of sensor reads the speed signal on your truck.

 

[volunteerff21]

Im not sure on a 94 but on my 96 the vss (vehicle speed sensor) went out one time and it did the exact same things yours is doing. But like I said mine was a 96 and it had a nv4500 transmission, that being said though I would bet your problem is also related to whatever type of sensor reads the speed signal on your truck.

x2 on the vss.

 

[KaZo]

Im not sure on a 94 but on my 96 the vss (vehicle speed sensor) went out one time and it did the exact same things yours is doing. But like I said mine was a 96 and it had a nv4500 transmission, that being said though I would bet your problem is also related to whatever type of sensor reads the speed signal on your truck.

Thanks for the response. I am fairly sure mine it's the NV4500 also. I assume the vss is the one on the transmission tail shaft? I'll start with replacing this piece and go from there.

 

[bow61509]

Thanks for the response. I am fairly sure mine it's the NV4500 also. I assume the vss is the one on the transmission tail shaft? I'll start with replacing this piece and go from there.

Yeah its in the tailshaft if a recall correctly its one bolt that holds it in