The ECM uses the CKP and CMP signal to calculate engine speed and position. The CKP sensor provides the ECM with a signal that indicates crankshaft speed and position. The CKP contains a permanent magnet that creates a magnetic field. The signal is created when the timing disk rotates and breaks the magnetic field created by the sensor. The ECM pins for the CKP sensor are CKP negative X1-2 and CKP positive X1-1.
NOTE: Engine will not operate without CKP signal.
Fault / Detection Management
An inactive CKP signal during cranking is detectable by the ECM. During engine cranking the ECM monitors the CMP signal and Injection Control Pressure (ICP) to verify the engine is rotating. If the CKP signal is inactive during this time a DTC will be set. Electrical noise can also be detected by the ECM, if the level is sufficient to effect engine operation a corresponding DTC will be set. An inactive CKP signal will cause a no start condition.
CKP Diagnostic Trouble Codes (DTCs)
DTCs are read using the EST or by counting the flashes from the amber and red ENGINE lamp.
DTC 146
CKP signal inactive
• DTC 146 is set by the ECM when CKP signal is not detected while the CMP signal is active or ICP has increased.
• DTC 146 can be set due to an open short to ground or voltage source in the CKP circuit. A failed CKP sensor can also set DTC 146.
DTC 147
Incorrect CKP signal signature
• DTC 147 is set by the ECM when the CKP signal has too few or many transitions per engine rotation.
• DTC 147 can be set due to an electrical noise in the CKP circuit or a failed CKP sensor.
Tools
• EST with MasterDiagnostics® software
• EZ-Tech® interface cable
• Digital Multimeter (DMM)
• Breakout Box
