91 Chev Lumina Speedometer Failure

The other day while cruising, my cruise, speedometer and odometers failed simultaneously. Following this the Service Engine Soon light came on only intermittently (not sure if related). I am wondering if it is the Vehicle Speed Sensor causing all three functions to fail. I inspected the sensor and found the wires severed at the sensor: it appears as though they were rubbing on the drive axle. I repaired the wires and am still having the same difficulty. I tried checking the sensor in position with a voltmeter and got no signal. I am not sure what all the sensor consists of for replacement. Anyone had thisproblem before??

is this the speed sensor at the tranny? When you repaired the wires, did you solder them, or just twist the together and tape them? Did you disconnect the negative battery cable to clear any codes? Try that. Otherwise just replce the speed sensor, i dont think they are that expensove, and if you have it all ripped apart, might as well do it while your there.

Thanks for the idea. I have not yet tried that. Is that all that is needed to clear the codes? Is the sensor not functional until the codes are cleared? I used a wire connector and then taped it thoroughly. Your 2001 looks a little nicer than my 1991...

thanks, yeah, I dont know if unhooking the battery will really do anything, but you should always disconnect the battery when replacing any sensors, or doing any wiring. You said wire connector? You mean crimp connector? Those usually arent the best to use. I would recommend cutting, soldering, and heat shrink tubing myself. Let me know how everything turns out. Good luck

also, make sure they are routed away from any moving parts, as the drive axel might have severed them again. But if you cut into it again, make sure you disconnect the battery, I've heard of computers being fried because of not unhooking battery's while working with sensors. Just a thought. Thats where I would check next, your computer. If the wires were cut, they probably were shorted to ground, and could have possably fried that curcuit in the ECM itself. If you have time, pick up an esm from a junkyard and switch them out. Make sure your cars are the same, with the exact same motor. just a thought. I myself would try replacing the sensor first. Or maybe even take it to autozone and see if the can tell you whats happeneing with the computer. They plug in the scanner and tell you for free. Keep us informed.

I tried what you said about disconnecting and reconnecting the battery cable...no luck. I don't understand though how a short in thta circuit would cause any issues as the sensor is not powered (i.e. it is a magnetic/reluctnace type sensor), and it only produces a small voltage when activated by the turning axle...elect. is not my forte though. I think I will try a new sensor (from the wrecker)...I did try testing the voltage at the sensor while turning the axle and got nothing. It is not a really easy area to access though.

yeah, thats just the thing, shorted wires to the sensor may not harm the sensor, however, you can almost bet that it wasnt very good for the computer. I'm not sure how it works exactly, how many wires are in the plug for it? 2 or 3? I know that computers usually send a reference voltage out to the sensors (usually 5 volts), and then measure the voltage coming back. Thats usually how it works. So if your computer saw a spike of 5 volts, your ecm could be smoked. Make sense? I'm not sure about this in your case. And also, if the speed sensor is like you say, (produces a voltage while the axel is turning) then if the wires were shorted, that may have smoked the sensor itself due to being short circuited. But anways. Try your donor sensor, make sure all the wires are connected together correctly, and if you can, maybe try and trace the wires even farther back. maybe they came in contact with an exhaust manifold somewhere. Anything's possible. Also when connecting the wire plug to the sensor, spray the contacts with a little wd40 and make sure its seated snugly. Good luck.

tBlake, I finally got it all sorted out. It turns out that you were absolutely right about my connection/splicing method, I was not getting adequate contact. I reconnected and it is all working. As far as our earlier discussion about damage to the computer due to a short, in this particular case, I don't think it is an issue as I don't believe there is any voltage on this circuit when the wheels are not turning. I took out the sensor and cleaned it carefully, reinstalled it and carefully spliced the wires and used the shrink cover and all is well. Thanks a lot for the ideas.

The other day while cruising, my cruise, speedometer and odometers failed simultaneously. Following this the Service Engine Soon light came on only intermittently (not sure if related). I am wondering if it is the Vehicle Speed Sensor causing all three functions to fail. I inspected the sensor and found the wires severed at the sensor: it appears as though they were rubbing on the drive axle. I repaired the wires and am still having the same difficulty. I tried checking the sensor in position with a voltmeter and got no signal. I am not sure what all the sensor consists of for replacement. Anyone had thisproblem before??


my in laws gave us a lumina
speedo didn't work as well as cruse
and so on
ant way
the wires were bad in side the insulation
i replaced those wires it was fixed
but before i noticed the wires were bad
i took out the sensor and took it in to autozone
and you can do this at home if you have a volt meter
i think you have to have the volt meter in a/c
because the sensir creats alternating current (a/c)
like your house
and the computer uses that to drive speedo cruse modual
and so on

the end of the sensor is like a maginet
take like a key
pass it infront of the sensor
hold the two pretty close to gether
and if the object you are using has a hole in it even better
and watch the meter
should notice a reading

if you don't want to do this
just take it to autozone or any were else the should be able to test it

good luck

yeah, why didnt I know that? Duh, speed sensors generate an ac signal. Thank you. And glad to hear everything worked out for you mikehild.