DTC Confirmation Test (Overall Function Check)

NOTE: Use the following test to check overall EGR function. During this test, DTC may not be confirmed.

Malfunction is detected when EGR temperature sensor does not detect EGR flow under conditions that call for EGR. Possible causes are:

EGR valve stuck closed.
Defective EGR Control Backpressure Transducer (EGRC-BPT).
Vacuum hose leak or blockage.
Defective EGR Control (EGRC) solenoid.
EGR passage blocked.
Defective EGR temperature sensor.
Exhaust leak.

To check overall EGR function, start engine and warm to normal operating temperature. Raise drive wheels, and support vehicle. Shift transmission into a forward gear. Increase engine speed to 4000 RPM and check for EGR valve opening. EGR valve should open and close without sticking. If operation is not as specified, go to PROCEDURE . If operation is as specified, diagnose EGR temperature sensor or circuit failure. See DTC P1401: EGR TEMPERATURE SENSOR .