If you have a 97+ year you may need to do this when swapping PCMs or installing a reflash PCM


DTC P1631 THEFT DETERRENT PASSWORD INCORRECT


Important: While the PCM is in the Auto Learn Procedure, battery voltage must be maintained at all times. This procedure must be followed exactly as indicated or the procedure will have to be repeated from the beginning.

The times posted are minimum time can go over the limit but not under it





1.. Attempt to start vehicle (vehicle will start and stall) (in my case never got start only crank)'"after the engine has stalled leave the ignition ON for 10 minutes (security light will remain on for 10 minutes and then go out).


2. After the Security lamp turns OFF, turn the ignition off 'for 30 seconds.


3, Again, attempt to start vehicle (vehicle will start and stall), (again crank no start for me C-N-S) after the engine has stalled leave the ignition on for 10 minutes (security light will remain on for 10 minutes and then go out).


4. After the security lamp turns OFF, turn the ignition off for 30 seconds.


5. Again, attempt to start vehicle (vehicle will start and stall) , (C-N-S); after engine has stalled leave the ignition on for 10 minutes (security light will remain on for 10 minutes and then go out) or until DTC P1631 sets.


6. Turn the ignition off for 30 seconds.


7. Turn the ignition on wait 30 seconds..


8. Attempt to start the engine.


Does the engine start and operate normally, IF NO: REPEAT # 1-8.


Conditions for clearing the DTC


. A History DTC will clear after forty consecutive Warm - up cycles" If no failures are reported by this or any Other emission related failure.


. PCM battery voltage is interrupted. . Using a scan tool.