Chart C-7 EGR System Check

Chart C-7:

EGR Schematic:

CIRCUIT DESCRIPTION
The digital (EGR) valve is designed to accurately supply EGR to an engine independent of intake manifold vacuum. The valve controls EGR flow from the exhaust to the intake manifold through three orifices which increment in size to produce seven combinations. When a solenoid is energized, the armature with attached shaft and swivel pintle is lifted, opening the orifice. The flow accuracy is dependent on metering orifice size only, which results in improved control.

NOTE: If the digital EGR valve shows signs of excessive heat check the exhaust system for blockage (possibly a plugged converter) using the procedure found on Chart B-1. Refer to System Diagnosis/Procedures/ Diagnostic Charts/Chart B-1. B Charts
If the exhaust system is restricted, repair the cause. One possibility is an injector which is open due to one of the following reasons:
1. Stuck valve ball.
2. Grounded driver circuit.
3. Defective Powertrain Control Module (PCM).
If any one of these conditions is found, the oil should be checked for fuel contamination.

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

1. Diagnostic trouble code(s) (DTC)s 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. Number 3 solenoid has the large port and may stall the engine when energized.