Neon L4-2.0L DOHC (1996)
Crankshaft Position Sensor: Description and Operation
No Crank Reference Signal at PCM Trouble Code
Name of Code:
No Crank Reference Signal at PCM
When Monitored:
During engine cranking, with battery voltage less than 11.5 volts and manifold vacuum present.
Set Condition:
No signal from the crankshaft position (CKP) sensor during engine cranking or there is a camshaft position sensor signal without a CKP sensor
signal.
Theory of Operation:
The crankshaft position sensor is a hall-effect type sensor used to detect crankshaft speed and position. The PCM supplies 8 volts and a sensor
ground to the CKP sensor. The crankshaft position sensor signal circuit has a 5-volt pull-up from the PCM. The sensor signal is created by the
notches in the crankshaft pulse ring passing under the sensor. When a notch is under the sensor, the signal remains at 5 volts. When there isn't a
notch under the sensor, the signal drops to 0.3 volt.
Possible Causes:
-
Open or shorted 8-volt supply circuit
-
Open sensor ground
-
Open or shorted signal circuit
-
Excessive clearance between the sensor and crankshaft pulse ring
-
Damaged crankshaft pulse ring
-
Failed sensor
-
Failed PCM
-
Connector terminals
-
Connector wires
