Camshaft Position Sensor Hall Effect (TBI Federal)
- A malfunction in the camshaft position sensor circuit will set diagnostic trouble Code 42. For testing procedures, see TESTS W/CODES
article in this section. Use the following procedure to diagnose camshaft position sensor.
- Ensure ignition is off. Disconnect ECM 24-pin electrical connector C2 (Yellow). ECM is located behind left side of dash. Remove distributor cap from distributor. Remove rotor and signal rotor cover from distributor housing.
- Using voltmeter, probe ECM 17-pin electrical connector C1 (Green - still connected) terminal No. 1 to ECM 24-pin electrical connector C2 (Yellow See Fig 1
. Turn ignition on. Ensure Camshaft Position (CMP) sensor magnet is free from any metal particles.
- CMP sensor voltage with signal rotor inserted between hall element and magnet (magnetic flux cut off) should fluctuate between 0-1 volt. See Figure
. If voltage is as specified, go to next step. If voltage is not as specified, check for faulty wiring and ECM. If wiring and ECM are okay, replace distributor housing.
- CMP sensor voltage without signal rotor inserted between hall element and magnet (magnetic flux applied) should indicate battery voltage. See Figure
. If voltage is as specified, CMP sensor is okay. Turn ignition off and reverse disassembly procedure.
- If voltage is not as specified, check for faulty wiring and ECM. If wiring and ECM are okay, replace distributor housing. When testing is complete, reverse disassembly procedure.
Courtesy of GENERAL MOTORS CORP.