Signal Functions
The CKP signal source is a variable reluctance sensor mounted in the right front side of the engine block. The sensor reacts to a target wheel on the crankshaft. The target wheel is a 60 minus 2 tooth steel disk with 58 evenly spaced teeth and a SYNC gap (a minus 2 slot wide tooth). The sensor produces pulses for each tooth edge that passes it. The crankshaft speed is derived from the frequency of the CKP sensor signal. The crankshaft position is determined by synchronizing the SYNC tooth with the SYNC gap signals from the target wheel. Diagnostic information on the CKP input signal is obtained by carrying out accuracy checks on the frequency and duty cycle with software strategies.
The powertrain control module (PCM) uses the CKP and camshaft position (CMP) signals to calculate the engine speed and piston position. The CKP creates a signal used by the PCM to indicate cylinder identification in a particular bank. The CKP contains a permanent magnet that creates a magnetic field. The signal is created when the target wheel rotates and breaks the magnetic field created by the sensor. The engine will not operate without a CKP signal.
Engine Speed - Is determined by counting the 15 windows on the crankshaft gear each crankshaft revolution.
Injection Control Pressure - Engine speed is one of the controlling variables in the calculation of desired injection control pressure.
Exhaust Pressure - Exhaust pressure control is a function of engine speed and load.
Fuel Quantity Control/Torque Limiting - Engine torque and fuel is controlled and is dependent on engine speed. Fuel quantity is determined by engine speed.
This pinpoint test is intended to diagnose the following:
- CKP sensor
- harness circuits: CKP (+), CKP (-), CKP out and CKP shield
- PCM