I have a '91 Prelude, and in the past week the S3 light has flashed intermittantly, and when it does the speedo quits -- well, almost every time it quits. Get where I'm going, shut the engine down, come back out and fire it up and drive away with speedo working, no S3 light, until later it happens again. New wrinkle is that yesterday the S3 light began flashing, BUT the speedo still worked, this time the check engine light came on. Again, later I drove it with no S3 or check engine light and speedo working.

The Honda dealer (I took it to the dealer because my usual mechanic told me that his scanner would probably not give a conclusive answer) hooked it up and told me that I need a new computer. Says that '91s have only one and it needs to be replaced, well, if I want these issues to go away it needs to be replaced. He said that "anything higher than an 11 means it needs to be replaced, and we're getting a 13 and a 17." But, he did say that it was okay to drive.

Car is running, shifting fine. Thoughts, anyone? Thanks.

 

No one?

 

Check your vss (vehicle speed sensor).

 

Your car might be running lean or if not go to the forum on hondata.com/forum

 

number 13 and 17 are just trouble codes. if he is telling you that you need to replace your ecu because your ecu is setting trouble codes, i would not take a lawn mower to him.

13 - - barometer pressure sensor malfunction.
17 - - vehicle speed sensor malfunction.

 

Like we said in pp.com, its your VSS sensor. It needs to be replaced.

And since when can any mechanic hook up an OBDII scanner to an OBDI car???
You have to jump the ECU at the passenger shock tower in the engine bay, and for the TCU you have to pull down the carpet on the passenger side floor and you will see the TCU is to the left of your ECU and will have an eye with a red flashing LED.

The only time you will need to replace an ECU or TCU is if you submerge your car in a lake or gone through an electrical storm that hit you car full of lightning bolts.

ECU's and TCU's do not go bad as most people seem to think. The are rather pretty solid especially if they are OEM and not been tampered with.

The most common issue with all Honda's and especially this one in particular is the VSS sensor, once it starts to go bad it will act funny, and go out sporadically and then setup the check engine light as well.