Monitor Description

The ECM illuminates the MIL and stores a DTC immediately when either one of the following conditions, which could cause catalyst deterioration, is detected (2 trip detection logic).

• Within the first 1000 crankshaft revolutions of the engine starting, an excessive misfiring rate (approximately 40 to 60 misfires per 1000 crankshaft revolutions) occurs once.
• An excessive misfiring rate (approximately 20 to 50 misfires per 1000 crankshaft revolutions) occurs a total of 4 times.

The ECM flashes the MIL immediately when either one of the following conditions, which could cause Three-way Catalytic Converter (TWC) damage, is detected. Also, the ECM stores a DTC when either one of the following conditions is detected (2 trip detection logic).

• At a high engine speed, a sufficient amount of misfires to damage the catalyst occurring within 200 crankshaft revolutions is detected once.
• At a normal engine speed, a sufficient amount of misfires to damage the catalyst occurring within 200 crankshaft revolutions is detected 3 times.