'92 Diablo CEL will not flash --- any ideas?

Got both CEL's lit up, and after going through the cycling ignition on/off procedure to get the lights to flash (in order to determine what codes are present), the lights will not flash --- they simply remain "on" steadily.

Any thoughts as to what could be wrong ---- is their a separate "flasher relay / controller unit" that could be bad as well? Or, is the flash function controlled within the LIE ECU circuitry?

Thanks for any ideas.....

 

Thanks Mick ---

I'm cycling on/off 3 times, then switching back "on" for the 4th time --- as that is my understanding of how the "flash" function is supposed to be activated. Should I try to cycle more times?

The car appears to run fairly well once started. Power seems reasonable while driving with no obviously noticeable missing or stumbling. However, it often has difficulty starting (hot and cold). Also, at idle following a "cold" start, the car searches for a steady warm-up speed --- fluctuating between about 2000 and 1000 RPM. I assume this is not normal, and that it should idle fast (perhaps even as high as 2000?), but steady, until warm-up is complete, and then idle speed should drop down to around 1000 and hold?

In lieu of being able to retrieve any codes, so far, I'm just starting a generic, systematic check of the basics --- vacuum leaks, fuel delivery, spark delivery, battery voltage, alternator output, supply voltages to all engine management devices, fuses, relays, etc. I will probably "stumble" across the culprit.

....but, it sure would save me a alot of time if I could narrow down the scope a bit

Battery is new and being kept fully charged with a tender prior to all starts, btw.