Comprehensive Component Monitor —CCM I/M Monitor
The CCM continuously checks all inputs and outputs from all the sensors, actuators, switches and other devices that provide a signal to the computer. The comprehensive component monitor is always looking for a short, open, out of range value, functionality and “rationality.”
What is rationality in a monitor?
The simple answer is this; the computer is checking to see if the sensor’s value makes sense. The computer compares all other inputs and against information in the computer’s memory to see
if the values are logical given the current operating conditions.
Here’s and example of rationality
The computer sees a throttle position sensor that shows the throttle is wide open. However, the engine is at idle RPM, the speedometer is at 0-MPH and all other sensor like air flow through the MAF are more in line with the engine being at idle.
Based on all the available data, the wide open throttle data isn’t rational. In this case, the throttle position sensor signal would fail the rationality test.
Comprehensive Component Monitor — where it’s used
CCM is supported by both “spark ignition” vehicles and “compression ignition” (diesel) vehicles. The Comprehensive Component Monitor may set on either a single “One-Trip” event or a “Two-Trip” Monitor, depending on the component.
©, 2022 Rick MuscoplatPosted on by Rick Muscoplat