No Crank Reference Signal at PCM

NAME OF CODE
No Crank Reference Signal at PCM

WHEN MONITORED
During engine cranking.

SET CONDITION
No signal from the crank position sensor is present during engine cranking, and at least 3 cam position signals have occurred.

THEORY OF OPERATION
The crank position sensor is a hall effect-type sensor used to detect the crankshaft speed and position. The Powertrain Control Module (PCM) supplies 5 volts and a ground to power up the sensor. The PCM also supplies a 5-volt pull up voltage. The sensor signal is created by the slots passing under the sensor. When a slot is under the sensor the signal is high (5.0V); when the metal between the slots is under the sensor, the signal is low (0.03V).

POSSIBLE CAUSES
- Open or shorted 5-volt supply circuit
- Open sensor ground
- Open or shorted signal circuit
- Excessive clearance between the sensor and flywheel or crankshaft
- Damaged flywheel
- Failed sensor
- Failed PCM
- Shorted VSS 5-volt supply circuit