Comprehensive Component Monitor

Comprehensive Component Monitor (CCM) monitors for malfunctions in any powertrain electronic component or circuit that provides input or output signals to PCM that can affect emissions and is not monitored by another OBD-II monitor. Inputs and outputs are, at a minimum, monitored for circuit continuity or proper range of values. Where feasible, inputs are also checked for rationality, outputs are also checked for proper functionality. CCM covers many components and circuits and tests them in various ways depending on hardware, function, and type of signal. For example, analog inputs such as Throttle Position (TP) or Engine Coolant Temperature (ECT) are typically checked for opens, shorts and out-of-range values. This type of monitoring is performed continuously. Some digital inputs like Vehicle Speed (VS) or Crankshaft Position (CKP) rely on rationality checks; checking to see if input value makes sense at current engine operating conditions. These types of tests may require monitoring several components and can only be performed under appropriate test conditions. Outputs such as Idle Air Control (IAC) solenoid are checked for opens and shorts by monitoring a feedback circuit or "smart driver" associated with the output. Other outputs, such as relays, require additional feedback circuits to monitor secondary side of relay. Some outputs are also monitored for proper function by observing reaction of control system to a given change in output command. An IAC solenoid can be functionally tested by monitoring idle RPM relative to target idle RPM. Some tests can only be performed under appropriate test conditions. For example, transmission shift solenoids can only be tested when PCM commands a shift.

The following is an example of some input and output components monitored by CCM. Components monitored may belong to engine, ignition, transmission, air conditioning, or any other PCM supported subsystem.

1. Inputs
   
   Mass Air Flow (MAF) sensor, Intake Air Temperature (IAT) sensor, Engine Coolant Temperature (ECT) sensor, Throttle Position (TP) sensor, Camshaft Position (CMP) sensor, Air Conditioning Pressure Sensor (ACPS) and Fuel Tank Pressure (FTP) sensor.
2. Outputs
   
   Fuel Pump (FP), Wide Open Throttle A/C Cutout (WAC), Idle Air Control (IAC), Shift Solenoid (SS), Torque Converter Clutch (TCC) solenoid, Intake Manifold Runner Control (IMRC), EVAP Canister Purge Valve, canister vent (CV) solenoid.

CCM is enabled after engine starts and is running. A DTC is stored in Keep Alive Memory (KAM) and MIL is illuminated after 2 driving cycles when a malfunction is detected. Many CCM tests are also performed during KOEO and KOER self-tests.