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swiftj ... 5/31/2019

1995 GMC C1500 Sierra SLE 6 Cyl 4.30L


What is Exhaust Gas Recirculation Sensor "A" Circuit High of car? What are the causes of P0406 OBD-II Trouble Code?

1 Answer

Partsavatar Canadaparts

What does that mean?

The EGR (Exhaust gas recirculation) system is intended to lower burning temperatures under certain conditions, thereby dipping oxides of Nitrogen (NOx) emissions. It does this by recalculating still exhaust gasses back into the cylinder to be burn with the fuel mixture. Inert exhaust gas burns slower and lowers the temperatures of burning. The EGR valve is computer proscribed and opens to allow the exhaust gas to run into the cylinders. The EGR valve may be vacuum operated. If so, a PCM (Powertrain control module) forbidden EGR vacuum solenoid is working to deliver vacuum to the EGR valve. While activated by the PCM, the EGR solenoid open, allow engine vacuum to tour to the EGR valve. This engine vacuum opens the valve, allowing exhaust gasses to pass through and into the combustion chamber. Extra EGR valves are electronic and directly controlled by the PCM. The PCM will activate solenoid that is integral to the EGR valve.

What causes the P0406 code?

• Faulty EGR valve sensor

• Open EGR sensor circuit

• Dirty EGR valve

• Disconnected wiring in EGR circuit

What are the symptoms of the P0406 code?

There will likely be no symptoms present when this code is presented. A code will be stored and a service engine soon lamp will be illuminated, although it may take multiple drive cycles.
Common mistakes when diagnosing the P0406 code?
Analysis of the P0406 code can be a easy matter or turn into a terrifying if step by step analysis is not perform and every step needed finished. This can cause the real problem to be over looked and unneeded repairs performed.

What repairs can fix the P0406 code?

• Replacing the EGR valve

• Repairing or replacing wiring harness as needed

• Repairing poor electrical connections

• Replacing the vacuum line

• Cleaning excessive carbon buildup


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