QuestionWhat else should I know about this code. I am aware it is an EGR fault.
AnswerThis code really indicates nothing more than the fact that the EGR isn't operating properly.
The EGR system operates as follows:
-- the green striped hose from the throttle body applies vacuum to the EGR valve and EGR solenoid
-- the yellow striped hose vents the vacuum back to the throttle body
-- the solenoid closes when commanded by the ECM to block the venting to the throttle body, which in turn causes a vacuum to be applied to the EGR valve.
-- a vacuum limiting valve is included in the green striped hose which limits the amount of vacuum to the EGR valve.
To test, start the engine and let it idle. With a pair of needlenose pliers, pinch closed the yellow striped hose. This should cause the engine to idle very poorly. If that happens, you've just verified the following:
-- The EGR valve is functioning properly.
-- The vacuum hoses are connected properly and are in good condition.
-- The EGR passage in the intake manifold is sufficiently clear for proper EGR operation.
Presuming a good result to the above test, I'd recommend replacing both the EGR solenoid and the vacuum limiting valve. The solenoid is known to have intermittent failures, and I know of no test specifications for the vacuum limiting valve or a way to conclusively test it.
