Modes of Operation

Both CKP sensors provide identical pulses, although one signal is shifted several degrees of crankshaft rotation to the other. This amount depends on whether the sensors are separate or integrated with each other. The two CKP signals allow the PCM to perform an angle-based decode operation. This is considered a self-clocked system, where one sensor acts as a clock and the other is a data signal. The advantage of angle-based decoding is the increased accuracy and consistency of signals, even during engine acceleration and deceleration. If one sensor is not operating correctly, the PCM uses a time-based decode operation. This mode will read the pulse width of the remaining signal, and thereby provide a means of back-up with the minimum of performance loss. Diagnostic trouble codes are available to accurately diagnose the ignition system with a scan tool.