*CHECKING THE EGR SYSTEM
For a complete wiring diagram Refer to Section 8W
Possible Causes
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VACUUM SUPPLY TO EGR SOLENOID
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EGR SOLENOID
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EGR VALVE
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Diagnostic Test
1.
VACUUM SUPPLY TO EGR SOLENOID
Turn the ignition off.
Disconnect the vacuum supply hose to the EGR Solenoid.
Connect a vacuum gauge to the disconnected vacuum supply hose to the EGR Solenoid.
Start and idle the engine.
Observe the vacuum gauge reading.
Does the vacuum gauge display vacuum above 24 inches of mercury?
Yes
No
2.
VACUUM SUPPLY TO EGR VALVE
NOTE:
The engine must be at operating temperature for this test.
Turn the ignition off.
Reconnect the vacuum supply hose to the EGR Solenoid.
Disconnect the vacuum hose at the EGR Valve.
Connect a vacuum gauge to the disconnected vacuum hose at the EGR Valve.
Start and idle the engine.
Observe the vacuum gauge reading for 30 seconds beginning at engine start up.
Does the vacuum gauge display vacuum above 14 inches of mercury for approximately 16.0 seconds from engine start up then drop to 0?
Yes
No
-
Check the vacuum hose between the EGR Solenoid and the EGR Valve for crack, kinks cuts, or other damage that may prevent proper vacuum operation. If the hose
is functioning properly, replace the EGR Solenoid.
-
Perform the ECM Verification Test Ver. 1.
(Refer to 9 - ENGINE - STANDARD PROCEDURE)
3.
EGR VALVE
Turn the ignition off.
Reconnect the vacuum hose at the EGR Valve.
Disconnect both vacuum hoses at the EGR Solenoid.
Using a vacuum tee connector, connect both disconnected hose ends at the EGR Solenoid.
NOTE:
This test will apply continual vacuum to the EGR Valve. If the EGR Valve is functioning properly, a dramatic loss of engine power will occur when attempting to accelerate
and/or load the engine.
Test drive the vehicle.
Does the vehicle exhibit a noticeable loss of power on acceleration?
Yes
No