OBD Diagnostic Monitors

OBD Diagnostic Monitors

The Engine Management System is continuously checked during vehicle operation by the Engine Control Module (ECM) Powertrain on-board diagnostic (OBD) facility.
Powertrain OBD incorporates six diagnostic monitors. Each monitor has an associated group of DTCs. The diagnostic monitors will complete the diagnostic test(s) if a specified service "drive cycle" is carried out.

The six diagnostic monitors are as follows:
- Heated Oxygen Sensors Monitor
- Adaptive Fuel Monitor
- Misfire Monitor*
- Catalyst Efficiency Monitor
- Evaporative System Monitor
- Comprehensive Component Monitor (Engine Management / Transmission)

* NOTE: If on the first trip, the misfire is severe enough to cause excess exhaust emission, the individual cylinder DTC plus DTC P1316 will be logged. The CHECK ENGINE MIL will not be activated. If the fault reoccurs on the second trip, the individual cylinder DTC plus DTC P1316 will be flagged, and the CHECK ENGINE MIL will be activated.
If on the first trip, the misfire is severe enough to cause catalyst damage (more severe than excess exhaust emission), the CHECK ENGINE MIL will flash while the fault is present and the individual cylinder DTC plus DTC P1313 (A bank [1]), DTC P1314 (B bank [2]) will be logged. When the fault is no longer present the MIL will be deactivated. If the fault reoccurs on the second trip, the CHECK ENGINE MIL will flash while the fault is present and the individual cylinder DTC plus DTC P1313 (A bank [1]), DTC P1314 (B bank [2]) will be flagged. When the fault is no longer present the CHECK ENGINE MIL will be activated.

REFERENCE: Refer to the applicable Electrical Diagrams for circuit information and acronym descriptions when using the DTC Summaries.