Crankshaft Variation Learn Procedure
Camaro & Firebird 5.7L Engines
- Install the scan tool.
- Apply the vehicle's parking brake.
- Block the drive wheels.
- Close the vehicle's hood.
- Place the vehicle's transmission in Park (A/T) or Neutral (M/T).
- Idle the engine until the engine coolant temperature reaches 65C (150F).
- Turn OFF all the accessories.
- Apply the brakes for the duration of the procedure.
- If the CKP System Variation Learn Procedure cannot be completed successfully, refer to DTC P1336 Crankshaft Position (CKP) System Variation Not Learned, in Diagnostic Trouble Codes section for additional diagnostic information.
- Enable the Crankshaft Position System Variation Learn Procedure with the scan tool.
- Slowly raise the engine speed to 4000 RPM.
- Immediately release the throttle when the engine speed decreases.
- Turn OFF the ignition for 15 seconds after the learn procedure is completed successfully.
Description & Operation
5.7L V8 Engines
CKP Sensor The crankshaft position (CKP) sensor is a three-wire sensor based on the magneto resistive principle. A magneto resistive sensor uses two magnetic pickups between a permanent magnet. As an element such as a reluctor wheel passes the magnets the resulting change in the magnetic field is used by the sensor electronics to produce a digital output pulse. The PCM supplies a 12-volt, low reference, and signal circuit to the CKP sensor. The sensor returns a digital ON/OFF pulse 24 times per crankshaft revolution.
Crankshaft Reluctor Wheel
The crankshaft reluctor wheel is mounted on the rear of the crankshaft. The wheel is comprised of four 90-degree segments. Each segment represents a pair of cylinders at TDC, and is further divided into six 15-degree segments. Within each 15 degree segment is a notch of 1 of 2 different sizes. Each 90-degree segment has a unique pattern of notches. This is known as pulse width encoding. This pulse width encoded pattern allows the PCM to quickly recognize which pair of cylinders is at top dead center (TDC). The reluctor wheel is also a dual track-or mirror image-design. This means there is an additional wheel pressed against the first, with a gap of equal size to each notch of the mating wheel. When one sensing element of the CKP sensor is reading a notch, the other is reading a set of teeth. The resulting signals are then converted into a digital square wave output by the circuitry within the CKP sensor.
Removal & Installation
5.7L V8 Engines
- Disconnect the negative battery cable.
- Raise the vehicle.
- Remove the starter.
- Disconnect the crankshaft position (CKP) sensor electrical connector.
- Remove the CKP sensor retaining bolt.
- Remove the CKP sensor.
- Install the CKP sensor.
- Install the CKP sensor retaining bolt. Tighten the CKP sensor to 25 Nm (18 ft. lbs.).
- Connect the CKP sensor electrical connector.
- Install the starter.
- Lower the vehicle.
- Connect the negative battery cable.
- Program the transmitters.
- Perform the CKP System Variation Learn Procedure.