Cadillac Repair: a/c econ control not working, pcm 5, climate control

Question
Hi--96 Sedan DeVille: After mechanic cleared computer codes and changed oil the a/c econ does not work. It stays on econ and will not go to A/c. This is the second time this happened after oil change. How can this be so???. First time it seemed to clear itself. A/c did work fine as did auto climate control. Any thoughts? Thank you.

Answer
IS or HAS the CHECK ENGINE light ever illuminated while driving the vehicle ?.

If it HAS or has NOT, Let's check for FAULT CODES via:

1. Ignition ON. Engine OFF.

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

3. CODES in the form of LETTERS & NUMBERS will appear followed by the word HISTORY or CURRENT with each code that displays.

4. The display will stop at PCM?

5. Write down these codes EXACTLY as they appear as if you were video taping them and let me know what they are.

6. Turn OFF ignition.