Cadillac Repair: 1991 Cadillac 5.7L transmission slipping, word history, climate control


Question
QUESTION: This car functions as it should in reverse, 1st, 2nd and 3rd, but will not shift into high or overdrive.  This problem just manifested itself.  I've been a stickler for maintenance, having the oil changed every 2500 miles and the transmission fluid changed every 35K, in fact, its been less than 2000 miles since having the transmission fluid changed.  The car has 218,000 miles and has performed excellently until now.  Please advise.

ANSWER: IS or HAS the CHECK ENGINE light ever illuminated on the dash ?. Does the cryuise control work ?.

---------- FOLLOW-UP ----------

QUESTION: The check engine light comes on occasionally, and the cruise only works sporadically.

Answer
OK, Lets access the computer and see what codes you get.

1. Ignition switch ON. Engine NOT running.

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

3. On your fuel data panel you will see LETTERS & NUMBERS appear along with the word HISTORY or CURRENT and then the display will stop at PCM?

4. Let me know what codes you get and if each code is either CURRENT or HISTORY.

5. Turn OFF ignition.