ECU, Wiring, Sensors
User avatar
By CamperCarl
#349241 Back Story:
I have a 95 Civic Lx Sedan. It had the D15b7 up until last November (motor ate a valve and cylinder 2 piston rings fried). I swapped in a D16Y7 I got for free (after a rebuild of course). I kept the manual trans, replacing the fluid and clutch. It runs like a champ, getting 40mpg. I cant complain.
A couple months ago the speed sensor started reading 5mph over. Last month the speedometer stopped working all together and was throwing CEL Code 17 (VSS Failure). I replaced the VSS a couple days ago (only the electrical part). It still didnt work after the replacement. So I swapped in a new gauge cluster, thinking that may fix it, but nope. The car is my daily and I noticed that when I hit a bump hard enough, the speedometer starts working reading the correct speed, then flicks around to different speeds and drops back to 0 and pops the check engine light (CEL Code 17, still).


What I did:
-I replaced the VSS with a brand new sensor (just the electrical part)
-I replaced the cluster (I have 2 spares)
-I checked all fuses
-The plug for the VSS is clean
-I am getting CEL Code 17 (VSS failure)

The only thing I haven't done is check voltages. I know. I know.

What I am looking for is somebody who has had the same problem and knows exactly how to fix it. I searched for the same problem that I am having but got the same answers: "replace cluster and replace sensor".
User avatar
By teal_dx
#349257 Reading that going over a bump changes things makes me suspicious that it could be a wiring issue. Do you have a volt meter? Checking the voltage may let you know, while someone else jiggles the wires.
User avatar
By CamperCarl
#349425 I figured it out. The ground for the speed sensor is on the thermostat housing with several other ground wires. I unscrewed the bolt and moved the wires. I immediately noticed that a wire had fallen off. To my surprise it was the speed sensor ground. There was just enough copper wire sticking out that it was grounding when I hit a hard enough bump. I cleaned up the thermostat housing. Stripped the wire and reinstalled it. It seems to be 2mph higher than what it should be according to the gps's I was using.
User avatar
By CamperCarl
#349479 Yes, it is 2mph off no matter what the speed is.

I have Mazda Miata Dassys 14x5.5 (aluminum enkei wheels).
The tires are just all seasons, 175/65R14.
User avatar
By teal_dx
#349483 Cause if your wheel overall diameter is off from stock, your speedo will be more off the faster you go. Like if it's 2 mph off @ 20 mph, it will be 4 mph off at 40 mph and 8 mph off at 80 mph.
A larger wheel will make your speedo read slower and a smaller diameter wheel will make it read faster than you're actually going.

So yours just must be an inaccurate speedo. :?
User avatar
By CamperCarl
#349539 :? it's whatever :?

Atleast it will keep me from speeding! :thumb:
By express21
#351473 what is the colour of the ground wire for the vss?
By HeikDiesel
#351529
express21 wrote:what is the colour of the ground wire for the vss?


Black.

Black/Yellow should be the 5V+ and Yellow/Blue is the signal back to the cluster