Cadillac Repair: 1996 Cadillac STS, pcm 5, cadillac sts

Question
Hi, Is it normal for the "Service Engine Soon" Light to come on and stay on for a couple start ups then go off for awhile and come back on.  Shouldn't the "Service Engine Light" stay lit until the codes are cleared?  How would you tell if the sensor is bad?

Answer
You need to obtain the CODES from the computer via the climate control panel.

1. Ignition switch ON. Do NOT start engine.

2. Simultaneously push and hold the OFF and WARMER (^) buttons on your climate control panel for 3 seconds and release them.

3. watch your fuel data display for LETTERS & NUMBERS to be displayed along with the word CURRENT or HISTORY with each LETTERS & NUMBERS that display.

4. The display will stop at PCM?

5. Tell me EXACTLY what you see in the EXACT order in which you see the LETTERS & NUMBERS and either the word CURRENT or HISTORY after EACH code that displays. Tell it to me as if you were video taping the screen.

6. Turn ignition OFF.