The Powertrain Control Module (PCM) sends approximately 5 volts to the Hall-effect sensor. This voltage is required to operate the Hall-effect chip and the electronics inside the sensor. A ground for the sensor is provided through the sensor return circuit. The input to the PCM occurs on a 5-volt output reference circuit. The Hall-effect sensor contains a powerful magnet. As the magnetic field passes over the dense portion of the counterweight, the 5-volt signal is pulled to ground (0.3 volts) through a transistor in the sensor. When the magnetic field passes over the notches in the crankshaft counterweight, the magnetic field turns off the transistor in the sensor, causing the PCM to register the 5-volt signal. The PCM identifies crankshaft position by registering the change from 5 to 0 volts, as signaled from the Crankshaft Position (CKP) sensor.
- Using a diagnostic scan tool, check for the presence of any Diagnostic Trouble Codes (DTC-s). Record and address these codes as necessary.
- If no codes are present, review the scan tool environmental data. If possible, try to duplicate the conditions under which the DTC set.
- If applicable, actuate the component with the scan tool.
- Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
- Look for the data to change, the actuation to be interrupted, or for the DTC to reset during the wiggle test.
- Refer to any Technical Service Bulletins (TSBs) that may apply.
- Turn the ignition off.
- Visually inspect the related wire harness. Disconnect all the related harness connectors. Look for any chafed, pierced, pinched, partially broken wires and broken, bent, pushed out, or corroded terminals.
- Perform a voltage drop test on the related circuits between the suspected component and the Powertrain Control Module (PCM).
- Inspect and clean all PCM, engine, and chassis grounds that are related to the most current DTC.
- If numerous trouble codes were set, use a schematic and inspect any common ground or supply circuits.
- For intermittent Misfire DTC-s check for restrictions in the Intake and Exhaust system, proper installation of Sensors, vacuum leaks, and binding components that are run by the accessory drive belt.
- Use the scan tool to perform a System Test if one applies to the component.
- A co-pilot, data recorder, and/or lab scope should be used to help diagnose intermittent conditions.