Intermittant speedo and chk engine lite on 91 accord

A guess - the Vehicle Speed Sensor (VSS) is failing. The engine management system likely cares how fast you are going, thus the Check Engine light. It could be worse. My wife had a friend whose late model Buick's VSS failed entirely while waiting at a light; the CEL came on. When she took off the electronically controlled transmission wouldn't shift out of first gear - after all, what gear should it be in if the car is not moving?

In your 91, the codes are probably gone after the light goes out. If it comes back, retrieve the codes

and record them. You will need a small shorting jumper - a short piece of small guage wire works well - to substitute for the "Code Reader" the manual describes. As mentioned on sheet 18 of the pdf, the connector you need to access is under the dashboard on the passenger side. Your approach to the "check engine" light is approximately right. The light is there to notify the driver of emission-related problems that often don't show up as operational problems; there are no critical warnings (like engine temperature or oil pressure) involved. It is really saying, "I have information for you." Rarely, the failure may cause the mixture to run very rich and prolonged hard driving could damage the catalytic converter. Because of that I recommend avoiding the freeway, or at least following behind heavy trucks if freeways are unavoidable, until you can determine whether fuel economy is near normal. Once that has been determined restrictions are off, but the light should be investigated when practical. If the light is accompanied by lots of misfiring or things like that, of course you have to respond to the other symptoms.

Mike

Thanks Mike, and for the pointer to Code Reader. Hmmm, by the way how did she get the Buick to stop?!

So it sounds like it's related to the speedo not working as well. It looks like a mechanical odo, how does that work? Is the speedo/odo all driven by electronics?

I'll try to catch the code and let you know. So far I appear to be getting my usual good mileage and no obvious problems.

Steve

Yes - I'm pretty sure the speedo/odo in the '91 is all electronic. Honda's been doing it that way for quite a while.

Mi9ke

I've just suffered a similar problem with my 91 prelude SI states model with a B21a motor. I'm getting an error code 17 on one computer and 4 on the other(can't remember which one is which). Honda quoted NZ$295 and two weeks and $10 shipping from Japan for the Vehicle Speed Sensor located on the transmission. I found the following link very helpful in diagnosing the fault.

Thanks! I'm checking it out . . .

Here is a link to figure out your fault code