I have a 91 accord that gets an 09 error after driving for about a minute. It does not occur when the car idles, regardless of how long, only after you start driving.
I've replaced the distributor assm (OEM honda) and checked the wiring from the dizzy to the ECU for both open and short to ground. Everything's good. And the car seems to run fine, before and after I get the error.

My question is, is there any reason not to drive the car regularly other than the annoying light? What does the CYP sensor actually do if the car is running fine?

Any feedback would be greatly appreciated.
Thanks

 

The CYP sensor is used by the ECU to calculate fuel injection timing. There is likely a loose connection somewhere in the CYP circuit. As soon as vibration causes the loose connection to break for just a moment, you get a CYP code. However, since the circuit has continuity almost all of the time, the engine is able to run fine. Just a theory, of course, but it seems to fit your problem.

Since replacing the distributor didn't fix the problem, we can assume for the moment that any loose connection would be outside of the distributor. If you haven't already, try testing the resistance of the CYP circuit between the wires coming out of the distributor and the ECU connector- in segments if need be. A loose connection will usually create some resistance. Alternatively, you could run temporary wires from the distributor to the ECU which would bypass any bad connections. GL

 

Thanks much for the info and the suggestion!!!
I'll give it a try.