Circuit Description

The PCM checks the validity of the signals used in the ION Sensing module at various engine operating conditions. The test is performed to evacuate the Combustion Quality (CQ) signal pulse width if it is within a predetermined range. If the CQ signal pulse width is out of the predetermined range, the fail counter will be incriminated. If the failure counter exceeds the calibration, then test is complete and a failure will be reported. If the sample counter threshold is reached before the failure threshold, then the test is complete and a pass will be reported. This test will detect an open/short in the CQ line circuit, ION Sensing module faults and analog input faults in the PCM.