What are the common causes of P049C?

EGR valve B stuck open letting too much flow through. A failed EGR B actuator holding the valve open. A leaking EGR B diaphragm or vacuum line. Carbon holding EGR valve B off its seat. Incorrect EGR B calibration in the control module.

Read EGR flow live data and confirm excessive flow. Inspect EGR valve B for carbon holding it open. Test the EGR B vacuum supply and diaphragm for leaks. Command EGR valve B closed and check that flow drops. Replace EGR valve B if it will not seat. Clear the code and retest.

P049C

EGR B Flow Excessive Detected

System: Auxiliary emission controls (P code)
Lamp: Check Engine Light
Category: Powertrain - Auxiliary Emissions Controls

What it means

P049C means EGR B Flow Excessive Detected.

Check these first

EGR valve B stuck open letting too much flow through
A failed EGR B actuator holding the valve open
A leaking EGR B diaphragm or vacuum line
Carbon holding EGR valve B off its seat
Incorrect EGR B calibration in the control module

What to do next

Read EGR flow live data and confirm excessive flow
Inspect EGR valve B for carbon holding it open
Test the EGR B vacuum supply and diaphragm for leaks
Command EGR valve B closed and check that flow drops
Replace EGR valve B if it will not seat
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.