91 Accord LX. Possible VSS problem?
 

I just bought a 1991 accord wagon lx used off craigslist with about 158,000 miles on it. Only had it for a week and already having a problem. Last weekend I started it up and put it into drive and the engine seemed to rev fine but very little forward motion was happening. As if it was in the wrong gear. S mode light was also stuck on.

After researching I took the TCU out to see if anything looked wrong. It didn't look to have anything wrong with it. I then pulled the ECU fuse and put it back and this seemed to solve it... temporarily.

A couple days later the S mode light began flashing on and off sporadically while driving and the car started having problems being in the correct gear like before. Pulling and replacing the fuse didn't work this time.

I checked the service check connector to see if I got any codes and the only thing I get is a solid check engine light when I have the paper clip in there.

I'm very inexperienced (as in none) at working on cars but if it's simple enough I'd really like to do this myself. I know I haven't pin pointed the exact problem just yet but after searching on here quite a bit it sounds like the VSS is a decent candidate.

Any suggestions for my next step? Other things I can check? Why am I not getting an error code I wonder?

I have also figured out that I need the valve cover gasket and the seals around the plugs to be replaced which I was going to do this weekend. I doubt this could be a part of the problem but thought I'd mention it.

When you jumped the service connector, did you jump it with the ignition off, jump it and then turn the ignition to II/ON? If it's a transmission code, the S light should flash the code, not the check engine light.

As far as it beging the VSS goes, do you're cruise control and speedometer work? VSS sends a signal to both of those, if they both work you can pretty much rule them out.

Valve cover gaskets and plug seals are an easy job and I recommend the Fel-Pro kit, which I believe most parts stores sell, I know Napa does. If you can do that job on your own, you know something. Most of the people that come in asking a question know nothing, zip, nada, zilch.

Good luck!

Take you car to the local Advance or AutoZone and have them pull your codes to read..

The cruise control and speedo work fine. At least they just did when I took the car around the block and everything else seemed to work fine. No flashing S light, no shifting problems. S mode button worked, cruise worked... I'm stumped. I wonder if this being a problem that seems to come and go as it pleases without me doing anything is a usefull clue. It is probably why I'm getting no error codes though. I guess I'll have to wait for it to act up again before I can get those.

edit: part of the reason I took it out was to see if the Schucks down the street could give me the codes. But the thing drove fine and as it turned out, that Schucks couldn't read them.

I put the paper clip in first then turned the key. No codes, no flashing S light. Just a solid check engine light that went off when I took the clip out. Perhaps I have to wait until the problem happens again because it drives fine now.

Anything else I can try in the meantime?

Ok. So the problem seems back for good. Only works in 1st and 3rd if I put it there manually. Otherwise it seems to stay in 3rd. S light pretty much on constantly except when at a stop. As soon as I coast it flickers on. Tried to get the error code again. Still no luck. the S light stays on solid. Both speedo and cruise seem to work fine even though it's not shifting right. I take it this means its not the VSS? Maybe the TCU under the floor board? I pulled it and everything looks fine but who knows.How can I pinpoint this? I've considered just paying to get diagnosed but I'd like to keep it DIY if I can. I need help though.

You may have to count the code(s) on the led on the TCU. Pull back the pass. side carpet and there should be a little window with a LED on it.

I don't know when honda switched to using a flashing S light to get the code.

Problem described suggest failed Trans Control Unit. This was a common problem w/ early 90's Accords. Symptoms are failure to shift, S-light stuck on, and most important problem is fixed temporarily by resetting the TCU w/ by pulling the BackUp fuse. I don't think it's described on this forum, but a google search should turn up the TSB for this problem.

Fix is replacement w/ a rebuilt or used unit. New price is wildly outrageouos. Used are available via car-part.com and search for your zip code. Check online for repair services that will repair your unit.

good luck