New member, first read of the forums:

I know this is an old post, but I just got the same issue with my 98 Civic LX 5spd. Codes P1298, P0500, P0141 and P0135. High input, speed sensor and O2. Speed/tach jump all over the place, lights are pulsing... Any help. This post did not have a conclusion that I could see.

Thanks!

Ted

 

the speed sensor is the sensor that would cause the rpm guage to jump around and that sensor is located on the transmission. there is a little sensor ontop of a little spline that plugs into the top of the tranny. The o2 is located on the exhaust manifold and sometimes a 2nd one is right by the cat. The sensor is pretty cheap but the o2 sensors are kind of pricy.

 

Hello, I have the same problem and also my headlights dim. have same codes but car runs and starts just fine. Any one knows why the headlights dim.

 

This is a common problem for 6th generation Civics.

Check whether fuse 15 is blown. The problem is typically due to an electrical short in the wire harness running between the engine and firewall. See this link for more detailed information:

http://autorepair.about.com/library/faqs/bl021d.htm

 

Nice link Ron, I'm going to have to change that design a little and prevent that from happening to my Civic