riphamilton

I drive 97 accord/132K miles/get around car. A month or so ago I turned the ignition and before the engine started the speedometer jumped to 20 or so and hovered there for a second.

While driving it will hover around 20, although at random times it will kick in and function like normal. This tends to be on the highway, after the car has been on for some time, but I may be just trying to put a pattern to it. It could just be random.

Can anyone give any advice as to where to start the detective process? I can change my oil and tires ... a basic novice.

thanks in advance for any help

gianinline

I have a question for you. Maybe this could be the case (as it had happened to me and other members had seen something similar).
Do you have any "glow gauges" or anything that isn't the factory gauges on your dash?
If yes, the problem could be caused by the "gauge face" peeling and getting the needle stuck at a certain point. For me, my old "gauges" would stop the needle at 60mph..... until I removed the gauges faces...

standbackimapro

Same thing happend to my dads car a while ago, Turned out to be the VSS, (Vehicle Speed Sensor)

But as gianinline said, my friend had aftermarket gauges, and the needle would go up to like 25, and stop there, but after he hit like 65 it would shoot up to the actually speed

Chiovnidca

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by riphamilton &raquo;</TD></TR><TR><TD CLASS="quote">I drive 97 accord/132K miles/get around car. A month or so ago I turned the ignition and before the engine started the speedometer jumped to 20 or so and hovered there for a second.

While driving it will hover around 20, although at random times it will kick in and function like normal. This tends to be on the highway, after the car has been on for some time, but I may be just trying to put a pattern to it. It could just be random.

Can anyone give any advice as to where to start the detective process? </TD></TR></TABLE>
Most likely a bad gauge. Does it twitch up annd down whenthe the car is moving very slow?

thatasiankidtony

ha guess i'm not getting the glow guages then

moyospeed

I would also like to know, the same happen to me today but I reached my destination and came back the car was fine

flyinga

I am having the exact same problem. I am thinking it is the speed sensor.
I was hopeing someone else has had the same problem. Do U have a stick or
automatic. I had a 90 dx automatic and when the speed sensor went bad the car
wouldn't shift right and it tripped a diagnostic code. Unfortunately, my 96 ex stick
isn't throwing any code. I am actually leaning toward a speed sensor, and hopeing its not the spedometer...

TOOLMAN1966

I had the Speedometer indicating 20mph and Odometer not working problem, half the time. The other half it worked perfectly. Mine is a 1998 Civic EX. My problem was a broken solder connection (often called a "cold solder joint") on IC1 pin 10. My circuit board is the one pictured by REVOAPPAREL in this thread on 8-15-2012. This pin is one of the epoxy (or glued) pins. I used the soldering iron to remove this epoxy from the pin before re-soldering it. (The heat kind of crumples the epoxy so it can be scraped off with the iron tip.) The Vehicle Speed Sensor signal comes into IC1 on this pin, but also on IC1 pin 12, and IC2 pins 10 and 15. __ I found which solder connection was broken in the following manner: Removed the circuit board from the speedometer/odometer mechanism (it pulls right off.) Attached a 12 volt power supply to IGN and GND. Used a voltmeter to read COS & SIN voltages. These 2 voltages tell the speedometer needle where to point. (RED voltmeter lead on COS+ and BLACK voltmeter lead on COS-.) (Don't look at the voltages with respect to GND. The speedometer doesn't see that.) When the circuit board was working correctly, the COS voltage was 5.04 and the SIN voltage was 0.26. These are logic levels ONE and ZERO. (If you remember your Trigonometry, the COS of zero is ONE and the SIN of zero is ZERO. Zero is the vehicle speed.) When the circuit board wasn't working correctly (this is when the needle would indicate 20mph IF it was attached) COS voltage was 2.47 and SIN voltage was 1.80. When I read these WRONG voltages, I started touching things and when I pushed on IC1 the voltages became correct for a moment. Then I used a probe to push against each IC1 pin individually and found pin 10 was the pin not making contact. __ A person should be able to use this technique to find a bad solder joint anywhere on the board causing incorrect speedometer readings when the vehicle is sitting still. ___ I also traced out the entire circuit board and drew a schematic. If I figure out how to post a scanned pdf of this, I'll attach it. ___This is my first post to any automotive thread. I sincerely hope this helps many of you out with your speedometer indicating 20mph problems! Enjoy Troubleshooting! ((Toolman1966 _ APRIL 14, 2013))

NZXTInerTia

This thread is from 2006.