DTC P04D9 - Closed Loop EGR Control At Limit - Flow Too Low

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P04D9 - CLOSED LOOP EGR CONTROL AT LIMIT - FLOW TOO LOW

Description:	This DTC sets when the estimated exhaust gas recirculation (EGR) percent is less than the minimum limit for the operating conditions.
Possible Causes:	Aftermarket intake systems or exhaust systems Restricted airflow (intake or exhaust) Restricted EGR cooler EGR valve position sensor bias Exhaust pressure (EP) sensor bias Manifold absolute pressure (MAP) sensor bias Damaged intake throttle actuator Damaged EGR valve
Diagnostic Aids:	The presence of this DTC may indicate that the vehicle is operating in derate mode and may experience a loss of power. After repair, the vehicle may still display a system warning message. Drive the vehicle until the system warning message has cleared from the instrument cluster message center. This DTC is set when the pressure ratio of the MAP sensor signal and the EP sensor signal across the EGR valve is not as expected.
Application	Key On Engine Off	Key On Engine Running	Continuous Memory
All	GO to PINPOINT TEST W .