Hi folks,

I searched and couldn't find the exact same problem that I'm having. First off 1990 EXR 190,000 miles

Typically, after I start the and get moving the speedometer won't work or works erratically. Sometimes it will work fine, but not very often.

After driving for a few minutes and the speedometer is still acting erratically the green "S" will start flashing. Usually after driving for about 15 minutes and the car is fully warmed up the speedometer will start reading normally and displays the correct speed (I checked with smartphone app) without the needle twitching around -- the flashing "S" continues even though speedo is working fine. Very occasionally the check engine light will come on orange, but it doesn't unless the "S" is also flashing.

When the engine is turned off for a few minutes or more and then turned back on again everything will return to normal: the speedometer will work fine AND the "S" will no longer be flashing.

So basically the speedometer works fine when the engine is warm but not when cold. This makes me think the lubricant in the cable is lacking or is too viscous when cold.

I searched around and found this thread https://community.cartalk.com/t/spee...eed-up/72351/4 where someone lubricated the cable on an old car (not sure if Honda or not) and the problem was solved. Does it make sense that this would work on a 90 Accord? Any how-to advice?

 

The common diy thread on top of this forum has a link for reading the cel (check engine light). Read the codes from the CEL and the S light. Odd are high that you have a problem with the vehicle speed sensor (VSS). Not a rare problem on accords of this vintage.

Another quick test is to see if the cruise control works when the speedometer is not working.