Intermittent Engine Light / Trying to Obtain CEL Code

Last August (2015), my 1995 Honda Passport failed to accelerate when I shifted into drive. I took it in to the automotive shop and was told that my transmission needed to be rebuilt. Had that done. Parts on the invoice list include: Master Overhaul Kit, Filter, Solenoid Set, Low Reverse Band, Bushing Set, Torque Converter, Update Boost Valve, and Transmission Fluid. A week later I experienced similar issues. Brought it back and had the PRNDL switch replaced.

Since then, the vehicle seems to run well. No lurching, struggling, etc. However, for the past week or so the Check Engine Light has been coming on intermittently (though increasingly more often), especially when I drive on the highway and hit speeds at around 60 or 65 MPH. For the record, I never force this vehicle anymore than I have to. I don't punch the gas or drive over 65 MPH if I can help it.

Money is really tight, so today I thought I'd try checking the CEL code myself, which I've never done before. Inserted a jumper wire into the diagnostic connector and turned on the vehicle (did not actually start it). My CEL lit up for only a couple of seconds, like it normally does, before disappearing. My transmission light, however, began to blink steadily but never seemed to generate a code/pattern.

Is it possible I'm attempting to obtain these codes incorrectly?

I'm a novice when it comes to car repairs, but I'm always willing to learn. If you can give me some tips or steps to follow so that I can obtain a code and save myself a trip to the shop, I'll be happy to give it a go.

Sincerely,

Jason