Part 2 of 2

Code Chart 32:

EGR Solenoid Circuit:

CIRCUIT DESCRIPTION:
The Exhaust Gas Recirculation (EGR) system is controlled by the ECM. The ECM controls the vacuum being supplied to the valve by energizing and de-energizing a solenoid.

The ECM uses information from various engine sensors to determine when EGR is necessary. Once the ECM has requested EGR by grounding the solenoid circuit, the ECM will monitor engine operating conditions to determine if exhaust gas flow has entered the intake manifold. When the ECM tests for EGR operation and no change in engine operating conditions is indicated, a DTC 32 will set.

TEST DESCRIPTION: Number(s) below refer to circled number(s) on the diagnostic chart.

1. The remaining tests check the ability of the EGR valve to interact with the exhaust system. This system uses a negative backpressure EGR valve which should hold vacuum with engine "OFF." Be sure shop exhaust hose is not connected during Steps 1 and 2.

2. When engine is started, exhaust backpressure at the base of the EGR valve should open the valve's internal bleed and vent the applied vacuum allowing the valve to seat. Because the shop exhaust hose is not installed at this time, DO NOT allow the engine to run longer than 15 seconds.

Diagnostic Aids:
Low fuel pressure or lean fuel injectors may cause a DTC 32 to set. Related Tests, Information and Procedures It may be necessary to monitor fuel pressure while driving the vehicle at various road speeds and/or loads. If fuel pressure is normal, Chart C-2A Injector Coil Test Procedure