Circuit Description

EGR system is used to reduce NOx (oxides of nitrogen) levels. This system uses a linear EGR valve. Using inputs from various sensors, PCM controls EGR pintle position and can be monitored with scan tool. Actual EGR position should always be near the commanded or desired EGR position. If PCM detects a large difference between desired and actual EGR position, DTC P0404 will be set. DTC P0404 is a type "B" code.

Conditions required to set DTC are:

• IAT is greater than 41°F (5°C).
• EGR commanded ON (desired EGR position is greater than 0 percent).
• Actual EGR position differs from desired EGR position by more than 15 percent for 5 seconds.