EVPSensor

EGR Valve Position Sensor (EVP)

Group: Emissions and exhaust

The EVP sensor reports how far the EGR valve is open. The computer uses it to check that the valve follows its commands. On many vehicles it is built into the electronic EGR valve itself.

Contents

What does the EVP sensor do?

It is a potentiometer or a Hall sensor attached to the EGR valve stem. The computer commands an opening and reads the actual position; if they do not match, it logs an EGR performance code. EGR lowers combustion temperature and nitrogen oxides (NOx) by mixing part of the exhaust gas into the intake air.

Where is it located?

On top of the EGR valve, on the intake or exhaust manifold.

Signal type and reference values

  • 3 wires: 5 V, ground and signal.
  • Valve closed: roughly 0.3 to 0.9 V.
  • Valve fully open: 4.0 to 4.5 V.

Values are a guide only: always check the manufacturer's data for your engine.

Symptoms of a bad EVP sensor

  • Rough idle, or the engine stalls (valve open at idle).
  • Bucking and loss of power.
  • Pinging if the valve does not open.
  • Codes P0400 to P0409 and P0486.

How to test the EVP sensor step by step

  1. On the scan tool, compare desired and actual EGR position: they should match.
  2. Command the EGR with the scan tool and check that the position changes smoothly.
  3. Remove the valve and check for carbon: a stuck valve sets the same code as a failed sensor.
  4. Check 5 V and ground at the connector.

Trouble codes related to the EVP sensor

Frequently asked questions about the EVP sensor

Can the EGR valve be cleaned?
Yes, in many cases cleaning off the carbon fixes the problem. If the built-in sensor has failed, the whole valve is replaced.
Does deleting the EGR improve the engine?
It is illegal in most countries and increases NOx emissions. The computer will also turn the warning light on.

Updated September 25, 2026. Values are a guide only: always confirm them in the service manual for your engine.

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