Circuit Description

PCM checks validity of signals used in ION Sensing Module at various engine operating conditions. Test is performed to evaluate Combustion Quality (CQ) signal pulse width if it is within predetermined range. If CQ signal pulse width is out of predetermined range, fail counter will be incremented. If failure counter exceeds calibration, test is complete and a failure record will be reported. If same counter threshold is reached before failure threshold, then test is complete and a pass will be reported. This test will detect an open or short in CQ line circuit, ION Sensing Module faults and analog input faults in PCM. Conditions for setting DTC:

• Ignition voltage is between 11 and 16 volts.
• No Crank DTCs set.
• No cylinder ID DTCs set.