Hi.

Just last week, the speedometer on my 94 Honda Civic DX started malfunctioning. Sometimes it works and sometimes it doesn't. When it does work, it looks like there is no problem at all. So basically it's either at 0 or at the correct speed. Whats wrong with my car? Everything else seems to be working fine. Is this going to effect anything with how my car runs?

txgreasemonkey

Check/replace the Variable Speed Sensor (VSS) unit on the transmission. First, make sure the connection is corrosion-free.

darvin94

I have a 94 cx, and my speedo started doing the same thing about 6 months ago. It would work fine, and then just stop working alltogether. But last week it went haywire. It now reads that I am going 120mph at idle, and the needle is pinned on the underside of the "zero" marker when I'm moving. My odometer doesnt work either. Anyway, my car started out with the same symptoms as yours.

I looked up some stuff and found out that the EGR (exhaust gas recirculation system) is turned on when the vehicle is going more than 10 mph. This could lead to incomplete combustion in my case. probably not yours though.

Anyway, tell me if the VSS (vehicle speed sensor) fix worked. I'd like to figure a way of fixing this myself.

Jamodu

I'm not sure if this applies to a 1994 civic but I've had a similar problem on my 1997 car.

Basically, last year everything died leaving only an 'O2 Sensor Failure' Engine Code. After using Txgreasemonkey's K-Test, I found that the ECM had failed. I got the ECM reconditioned which got the car working again.

Shortly after, the speedo stopped working properly - erratically bouncing around from 0 to 140mph. I found and replaced a blown fuse in the drivers fuse box which solved the problem but later it blew again. This fuse also protects the alternator so when blown, the battery wasn't charging and the car lights pulsed (got brighter and dimmer). I put in higher fuses which sorted the problem for a while, but last week even 20A fuses were blowing as soon as the ignition was turned. After a bit of googling, I found this:

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If you look under the intake manifold at the rear of the engine there is a pack of wires. This pack rubs on the bottom of the intake and creates a short circuit which screws up the speedo, sets off the check engine light and gives a trouble code (if you know how to read the check engine flashes) that there is a problem with the O2 sensor, and sometimes the headlights would surge.

Just crawl under the car when it is up on stands and gently turn over the pack of wires under the intake to expose the bare wire or wires. Tape them up and away you go.

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I've been under the car today to have a look and as soon as I did, I could see straight away that the wires were exposed. A bit of insulation tape and 30 mins later everything is fixed again. I hope this helps some one in the future as it's been bugging me for 9 months and now I'm glad the problem's resolved.

jamesusa

This same issue recently occurred on my 95 civic DX 1.5L. It did not affect any of the other functions on my car. Six months later I replaced the entire speedometer/odometer assembly . Honda claims that only they sell the part. The part cost me $348 US dollars. The part # is 78115-sr3-a42. I would check at a scrap yard and online before paying this. Another example of poor manufacturing

txgreasemonkey

Yes, it's amazing the poor quality of most instrumentation--even on Toyotas. When you tear into them, you are shocked.