Comprehensive Component Monitor Diagnostic Operation

Comprehensive Component Monitor Diagnostic Operation
Comprehensive component monitoring diagnostics are required to monitor emissions-related input and output Powertrain components. The CARB OBD II Comprehensive Component Monitoring List of Components Intended To Illuminate The MIL is a list of components, features or functions that could fall under this requirement.

Input Components:
Input components are monitored for circuit continuity and out-of-range values. This includes performance checking. Performance checking refers to indicating a fault when the signal from a sensor does not seem reasonable (i.e. a Throttle Position (TP) sensor that indicates high throttle position at low engine loads or MAP voltage). Input components may include, but are not limited to the following sensors:
- Vehicle Speed Sensor (VSS)
- Crankshaft Position (CKP) sensor
- Knock Sensor (KS)
- Throttle Position (TP) sensor
- Engine Coolant Temperature (ECT) sensor
- Camshaft Position (CMP) sensor
- Manifold Absolute Pressure (MAP) sensor

NOTE: In addition to the circuit continuity and rationality check, the ECT sensor is monitored for its ability to achieve a steady state temperature to enable closed loop fuel control.

Output Components:
Output components are diagnosed for proper response to control module commands. Components where functional monitoring is not feasible will be monitored for circuit continuity and out-of-range values if applicable.
Output components to be monitored include, but are not limited to the following circuits:
- Idle Air Control (IAC) Motor
- Control module controlled EVAP Canister Purge Valve
- A/C relay
- Cooling fan relay
- VSS output
- MIL control