Non-Continuous Monitors

Onboard Diagnostics

OBD2 MONITORS

The other twelve Monitors are “non-continuous” Monitors. “Non- continuous” Monitors perform and complete their testing once per trip. The “non-continuous” Monitors are:

Oxygen Sensor Monitor

Oxygen Sensor Heater Monitor

Catalyst Monitor

Heated Catalyst Monitor

EGR System Monitor

EVAP System Monitor

Secondary Air System Monitor

The following Monitors will be standard beginning in 2010. The majority of vehicles produced before this time will not support these Monitors

NMHC Monitor

NOx Adsorber Monitor

Boost Pressure System Monitor

Exhaust Gas Sensor Monitor

PM Filter Monitor

The following provides a brief explanation of the function of each Monitor:

Comprehensive Component Monitor (CCM) - This Monitor continuously checks all inputs and outputs from sensors, actuators, switches and other devices that provide a signal to the computer. The Monitor checks for shorts, opens, out of range value,

functionality and “rationality.”

Rationality: Each input signal is compared against all other inputs and against information in the computer’s memory to see if it makes sense under the current operating conditions. Example: The signal from the throttle position sensor indicates the vehicle is in a wide-open throttle condition, but the vehicle is really at idle, and the idle condition is confirmed by the signals from all other sensors. Based on the input data, the computer determines that the signal from the throttle position sensor is not rational (does not make sense when compared to the other inputs). In this case, the signal would fail the rationality test.

The CCM is supported by both “spark ignition” vehicles and “compression ignition” vehicles. The CCM may be either a “One-Trip” or a “Two-Trip” Monitor, depending on the component.

Craftsman 14063