The cam sensor interrupter (magnet) may become demagnetized and/or fall off of the camshaft gear causing the Check Engine Light (Service Engine Soon) light to illuminate. On higher mileage vehicles it would be advisable to replace the timing chain and gears if this problem were to occur as the timing cover must be removed to replace the interrupter.
Check Engine Light Due to Cam Sensor Interrupter Fault on Buick Park Avenue
Average mileage: 170,000 (170,000–170,000)
Engine affected: 3.8L V6
5 people reported this problem
1991 Buick Park Avenue - 3.8L V6 170,000 mi, Visitor
Check engine light showed a code for camshaft positioning sensor circuit. Camshaft sensor magnet fell of the cam gear. Took cover off and replaced the magnet. Works like new!