We were driving to the mall and my girlfriends speedometer started acting up. It moves all over the place and shifts funny when its moving. When the speedometer remains steady it shifts smoothly, but once it starts moving weird it shifts very rough. Sounds like a sensor problem but i don't know much about civics.( I work on a suzuki samurai) Any ideas?

 

This is probably the vehicle speed sensor. It's on the top of the transmission in the back, between where the two CV axles go into the transmission. Make sure it is securely plugged in. Also while you're back there check the ground wires on the thermostat housing (where the LOWER radiator hose meets the engine). If it's a 96 to 98 model they have a problem with the wiring getting frayed on the intake manifold bracket behind the engine, which can disable the sensors.

If everything else checks out OK, it's a safe bet to just replace the sensor. It pushes into the transmission, with a bolt to hold it in place.

 

Alright ill check it out, and yes it's a 96.

 

That ground wire is in great shape. The pigtail was tight, Is there a voltage test i can run with a multimeter to see if it's acting up, before she spends a hundred dollars on a sensor? Also the odometer goes up while at idle when it's acting up.

 

Replacing the sensor did not work. Afterwards i drove it and it seemed to shift fine(for now) but the speedo is still all wacky. I think i may have checked the wrong ground. I'll recheck tomorrow. Any other ideas?

 

I found out that the 12v source wire was bad using the test here.(http://www.honda-tech.com/showthread.php?t=2601366) All i did to fix was found a switched 12v source in the fuse box and used that.

Hopefully this helps someone who has a similar problem in the future.