Firebird V6-3.8L VIN K (1995)
EGR Valve: Description and Operation
Figure C7-1 - Linear EGR Valve (Typical)
The linear 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 an orifice with a PCM controlled pintle. During operation, the PCM controls pintle position by monitoring the
pintle position feedback signal. The feedback signal can be monitored with a scan tool as "ACTUAL EGR POS." "ACTUAL EGR POS" should always
be near the commanded EGR position ("DESIRED EGR POS"). If a problem with the EGR system will not allow the PCM to control pintle position
properly, DTC P1406 should set. The PCM also tests for EGR flow; if incorrect flow is detected, DTC PO4O1 should set. If DTCs PO4O1 and/or
P1406 are encountered, refer to the Diagnostic Trouble Code Charts. See: Computers and Control Systems/Testing and Inspection
The linear EGR valve is usually activated under the following conditions:
^
Warm engine operation.
^
Above idle speed.
