Circuit Description

PCM checks validity of signals used in ION Sensing Module under following conditions:

• Deceleration Fuel Cut Off (DFCO) test is performed to evaluate Combustion Quality (CQ) signal pulse width.
• If it is below a predetermined value, the value it is expected to be during DFCO conditions. If the CQ signal pulse width is above the predetermined threshold, the fail counter will be incriminated. If the failure counter exceeds the calibration, then the test is complete and a failure will be reported.
• Power Enrichment (PE) test is performed to evaluate the Combustion Quality (CQ) signal pulse width.
• If CQ signal pulse width is above the predetermined threshold, fail counter will be incriminated. If failure counter exceeds calibration, test is complete and a failure is reported.
• Combustion Quality (CQ) test is performed to check if inappropriate CQ signal status were detected. If missing CQ pulses, multiple CQ pulses or CQ pulse width calculation errors were detected, failure counter will be incriminated. If failure counter exceeds calibration, test is complete and a failure will be reported.