QuestionQUESTION: The Service Engine Soon light just came up on my 1995 Deville with a 4.9 engine. What can cause that? How can I access the trouble codes for this vehicle?
ANSWER: Perform this procedure:
1. Turn ignition key to the ON position. Do NOT start the engine.
2. Simultaneously push and hold the OFF and WARMER buttons on your climate control panel for 3 seconds and release them.
3. In the fuel data display you will see LETTERS & NUMBERS appear and along with each LETTER & NUMBER that appears will be the the word HISTORY or CURRENT.
4. The display will stop at PCM?
5. I need to know EXACTLY what displays on the display in the EXACT order in which the LETTERS & NUMBERS display as if you were video taping them.
6. Turn ignition key OFF.
---------- FOLLOW-UP ----------
QUESTION: Here is the sequence.
CODE P039 HISTORY
NO IPC CODES
NO ACP CODES
NO SIR CODES
NO TCS CODES
PCM?
The Engine light did not appear the next time I started the car and did not appear again until now (3 day period).
AnswerOK, If you CLEAR the P039 history code from the computer, the check engine light should remain out unless you develop another problem.
1. Re-enter diagnostics and when you see PCM?
2. push and release the HI button and you will see PCM DATA?
3. Keep pushing and releasing the LO button until you see PCM CLEAR CODES?
4. Push and release the HI button and you will see PCM CODES CLEAR.
5. Wait 3 seconds and turn OFF the ignition switch.
6. This will CLEAR the P039 code from the computer.
