What is an EGR Valve?

The Exhaust Gas Recirculation Valve, or more commonly known as the EGR valve, controls the engines emission of nitrous oxidize or Nox. It helps your vehicles to efficiently burn unused fuel by recirculating a portion of your exhaust through the process again. This then reduces the amount of harmful gases your vehicle would produce.

Symptoms of a failing EGR Valve:

When Your EGR is about to fail, the most noticeable signs to look out for are:

  • Rough Idling
    This is when the EGR valve mechanism stays open when the engine is at a low RPM or idling (stopped at one space). The extra addition of exhaust gases will then cause the engine to go haywire.
  • Fuel Detonation Noise
    This is when the EGR valve mechanism remains shut when the engine is at a high RPM. This causes a high temperature in the combustion chamber due to the absent exhaust gas cooling effects, the production of the nitrogen compounds will further lead into more detonation which is burning the fuel without any ignition. This would cause detonation knocking noises in the engine.
  • Increase in Emission of Nox Gases
    This is when there is a spike in the emission of Nox gases.
  • Overall Erratic Engine Functioning
    This is when the engine starts to act erratically causing a drop in its efficiency.


What causes an EGR to Fail?

There are a number of different ways an EGR valve can fail, and many factors that can cause them to fail. We will go through the most common cause of failures an EGR can face and what can cause them:

The EGR system flow is insufficient.

This is caused by:

  • A clogged or restricted EGR passageway
  • The EGR valve stuck closed
  • Problems with the Differential Pressure Feedback Sensor (DPFE sensor) or hoses that lead to the unit which is specific to the Ford vehicles
  • Problem with the EGR vacuum switching valve which is specific to Toyota vehicles
  • A clogged catalytic converter or Diesel particulate filter (DPF)
  • Carbon build up on EGR temperature sensor
  • Vacuum supply issues at the (Vacuum operated EGR valve)
  • Electrical problems with the EGR valve control circuit


The EGR system flow is excessive.

This is caused by:

  • The EGR valve mechanism is stuck open
  • The air filter is clogged or dirty
  • There are intake leaks
  • There could be a problem with the turbocharger
  • An incorrect vacuum hoses connection
  • The DPEE sensor may be bad or damaged which is specific to the Ford or Mazda vehicles
  • There may be a fault with the EGR Control Back Pressure Transducer valve (EGRC-BPT) which is specific to the Nissan vehicles
  • There may be a fault with the EGR temperature sensor
  • There is a damaged or missing EGR valve gasket
  • There could be some problems with the EGR vacuum control
  • There could be some problems with the EGR switching valve
  • The EGR valve control circuit may be having electrical problems
  • The catalytic Converter may be clogged
  • The EGR vacuum Solenoid may be defective
  • There may be a restriction in the EGR passages, its usually caused by carbon buildup


Having Problems with your EGR Valve ?

Do not worry, UK Diesel Parts Stock a wide range of replacement Exhaust Gas Recirculation valves that will get you and you car back on the road in no time. We stock OEM and Aftermarket versions in our range meaning we have the part for everyone. We have an EGR Valve for everyone’s budget and requirements!


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