Cadillac Repair: 96 eldorado, service transmission, climate control

Question
check engine light comes on some times and goes off.service transmission comes on. the trans shifts a little harder when the light is on.  also there is a humming noise coming from the shifter.

Answer
You need to retrieve the CODES from the computer to see which codes are CURRENT or HISTORY.

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. The CODES will appaer in the fuel data panel and will individually read CURRENT or HISTORY.

4. I need to know the exact order in which the codes display as if you were video taping them.

5. Turn ignition OFF.