1. Introduction

The Monitor Status (mode 6) allows the OBD scan tool to display the monitor result, test value and test limit (malfunction criterion). A problem in the emission-related components such as the catalyst, EVAP and thermostat can be found by comparing the test value and test limit. The monitor status information is included under the "MONITOR STATUS" in the emission-related DTC sections.

The ECM (PCM) monitors the emission-related components. After the monitor, the ECM stores the monitor result and test value. The monitor result indicates whether the component is functioning normally or not (PASS or FAIL). The test value is the value that was used to determine the monitor result. When the test value is inside the test limit, the ECM determines the component is functioning normally (PASS). If the test value is outside the test limit, the ECM determines the component is malfunctioning (FAIL).