Code 42, Crank Angle Sensor CKT/No Signal For 3 Seconds

ECM receives a signal from Crank Angle Sensor (CAS) in distributor. This CAS signal is used to control spark advance. If CAS signal is lost, ignition timing will be fixed. Code 42 will set if CAS signal is not present with engine cranking, or if signal is lost after engine is started.

1. Checks White wire for a signal to ECM. Also checks for open circuit in White wire.
2. Checks for B+ to CAS circuit.
3. Checks for ground at CAS.

Fig 1: Code 42 Flow Chart, CAS Ckt./No Signal For 3 Sec.

Courtesy of GENERAL MOTORS CORP.

Fig 2: Code 42 Schematic, CAS Ckt./No Signal For 3 Sec.

Courtesy of GENERAL MOTORS CORP.