How to Replace the Crank Position Sensor in Vehicles

by Contributing WriterUpdated June 12, 2017

The Vehicles 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 Vehicles ignition timing and fuel injection.

Under The Hood:

 How to Replace the Crank Position Sensor in a Cadillac DeVille

Disconnect the wiring harness connector from the crankshaft position sensor by pulling the tangs on the side of the connector away from the plug and pulling the plug off the sensor.

Unbolt the sensor's retaining bolt, using the appropriate socket. Remove the sensor and its O-ring from the block.

Clean the mating surface on the block with a rag. Ensure that the new O-ring is on the new sensor. Install the sensor and tighten the retaining bolt firmly. Do not over-tighten the bolt, as you will damage the sensor.

Plug in the wiring harness connector, ensuring that it snaps into place.

Items you will need

  • Set of sockets

  • Shop rag

 How to Replace a Crank Position Sensor on a 2001 Blazer

Set the parking brake and chock the rear wheels. Lift the front passenger-side wheel off the ground. Place a jack stand under the lower control arm and lower the jack until the truck is resting on the stand. Disconnect the negative battery cable from the battery.

Slide under the front of the truck and unplug the electrical connector on the sensor. Use a 10mm socket and ratchet to remove the sensor retaining bolt that secures the sensor to the side of the timing cover. Twist and pull the sensor until it slips out of the cover.

Apply a small amount of silicon grease to the seal on the sensor and push it into place in the timing cover. Reinstall the retaining bolt and electrical connector.

Reinstall the battery cable. Raise the Blazer off the jack stand, remove the stand and lower the truck to the ground. Test drive the car to verify that the repair fixed the problem.

Items you will need

  • Wheel chocks

  • Floor jack

  • Jack stand

  • Socket set

  • New sensor

  • Silicon grease

 How to Replace the Crank Position Sensor on a Pontiac Bonneville

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.

Items you will need

  • Floor jack

  • Jack stand

  • Wheel chocks

  • Lug wrench

  • Socket set

  • Balancer puller

  • Balancer installer

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