Park/Neutral (P/N) Switch
Disconnect P/N switch connector which is located near the battery. Check continuity between terminals "A" (Black/White wire) and "B" (Red/Yellow/Black wire). There should be continuity between the terminals in Park and Neutral. Switch should be open in all other selector positions. Perform "wiggle" test on selector lever when in "D" position to ensure switch is adjusted properly and a short does not exist.
CAUTION:
If vehicle is operated with P/N switch disconnected, idle quality will be affected and a false diagnostic Code 24 may be set in ECM memory.