Chart C-7 EGR System Check - Port Fuel Injection

Chart C-7:

Chart C-7 Wiring Diagram:

CIRCUIT DESCRIPTION:

The digital EGR valve controls EGR flow through two different sized orifices which are normally closed by pintles held down by springs. The #1 orifice is small and the #2 orifice is larger. Independently controlled solenoids lift the pintles off the orifices when the ECM allows the current to flow through the solenoids by creating ground paths through two separate quad-drivers. Electrical circuit problems should result in Code 26 setting.

The ECM also test EGR flow by very quickly actuating each solenoid separately while the engine is idling under stable conditions. Failure of this test should result in Code 32 setting.

If Code 26 or 32 are present, those charts should be used. This chart provides a functional check of the EGR system.


TEST DESCRIPTION: The numbers below refer to circled numbers on the diagnostic chart.


1. Codes should be diagnosed using appropriate chart before preparing a functional check.

2. This step activates each solenoid individually. As you energize #1 or #2 solenoid, the engine rpm should drop. The #2 solenoid should have more affect than the #1 solenoid.