How to fix P0404 Code: Exhaust Gas Recirculation Control Circuit Range/Performance
The EGR valve reduces emissions by allowing burnt exhaust gases to go back into the engine. This lowers the engine combustion temperature, which reduces Nitrogen Oxide (NOx) emissions.
An EGR valve can be vacuum-controlled and electronically controlled with many different designs.
A P0404 code is set when the EGR Valve Position Sensor is reading above or below the specified range.
Common causes include a bad 5V reference voltage, an open or short, a bad EGR valve, and a bad sensor.

Possible Causes of a P0404 Code:
Wiring
EGR Valve
Sensor (differential pressure feedback (DPFE), manifold absolute pressure (MAP))

By using this information user assumes all risk of use.

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