The Pontiac Bonneville uses a crankshaft position sensor to supply the on-board computer with information relevant to the position of the crankshaft in degrees of crankshaft rotation. This sensor works on the principle of magnetic induction. As the tone ring located in the harmonic balancer passes through the sensor, the magnetic field in the sensor collapses and induces a voltage into the windings in the sensor. This produces an A/C sine wave that the on-board computer processes into a digital square wave and calculates the position of the pistons for ignition timing and fuel injection.
Remove the serpentine belt by compressing the spring-loaded belt tensioner. Use a 3/8-inch drive socket wrench from the socket set, inserted into the square hole in the tensioner arm, to compress the arm. .
Lift and support the vehicle, then remove the passenger side front wheel. Place a wheel chock behind the driver’s side rear wheel and set the parking brake. Jack the passenger front wheel up and place a jack stand under the subframe in the front of the vehicle. Lower the vehicle onto the jack stand. Remove the wheel and place the wheel and lug nuts out of the way to prevent tripping hazards.
Remove the 10 mm bolts that attach the splash shield to the car and set the splash shield aside. Locate the round harmonic balancer and pulley, and remove the large center bolt. The balancer may slide off the crankshaft; but if a puller is needed, one is available at the local auto parts store. This puller is specifically designed to remove the General Motors balancers used on late model engines.
Remove the sensor by unbolting it from the engine block and unplugging it from the wiring harness connector. Slide the new sensor into place and bolt it down. Then plug the wiring harness connector into the new sensor.
Install the balancer and tighten the center bolt securely. Reinstall the splash shield and bolts.
Install the wheel and lower the vehicle back onto the ground. Reinstall the serpentine belt.
Reset trouble codes with a hand held scan tool. Scan tools that will allow the resetting of trouble codes are available at the local auto parts store. Auto repair shops with this equipment will reset the codes for a small fee. Test-drive and make sure the code does not return.
