Took my recently aquired 22re for a interstate jog, and found that the check engine light will pop on at speed (over ~55 mph). It didn't come one until about 10 minutes of riding at this speed. Nothing appears wrong in the dash dials as far as overheating is concerned. Then when I backed off down close to 50 mph and below, the light went off.

Am I correct to assume that the diagnostic system will not indicate a problem unless the check engine light is on full time?

Any ideas or similar experiences??

 

No. The ECM will, or at least can, hold codes without the CEL actually being on. Do you have a manual? Jump the same two connectors in the DIAG box that you would to check the timing. Then turn the key on and count the blinks.

Here is a link from the manual: http://personal.utulsa.edu/~nathan-b...26diagnosi.pdf

 

Mine came on at a certain speed, it was the o2 sensor.