Symptoms of a Bad or Failing EVP Position Sensor

The EVP sensor is an emission system component found on certain vehicles. It is a part of the EGR system, the emissions system that recirculates exhaust gases back into the engine to reduce cylinder temperature and NOx emissions. The EVP sensor monitors the position of the EGR valve so that the computer can adjust it according to operating conditions. [When the sensor fails] it can cause problems with the functionality of the EGR system, which can result in increased emissions. Usually a bad or failing EVP position sensor will produce a few symptoms that can alert the driver of a potential problem that should be serviced.

1. Poor cold start performance

One of the first symptoms of a potential problem with the EVP sensor is poor cold start performance. If the EVP sensor fails it can send an incorrect signal to the computer, which will affect the flow of the EGR system. Improper EGR flow may cause engine performance issues, such as difficulty starting, rough idle, and even misfires, which may be most prominent at cold starts.

2. Check Engine Light comes on

Another symptom of a potential problem with the EVP position sensor is a Check Engine Light. If the computer detects an issue with the EVP position sensor or circuit it will set off the Check Engine Light to alert the driver of a potential issue. The Check Engine Light can also be set off by a wide variety of other problems, so having the vehicle scanned for trouble codes is highly recommended.

3. Failed emissions test

A bad or failing EVP sensor can also result in a [failed emissions test]. If the EVP positions sensor malfunctions and affects the functionality of the EGR system this may result in an increase of NOx emissions. For states with strict emissions requirements, the vehicle may not be able to be registered until the issue is fixed.

The EVP position sensor is an emissions component, and any problems with it can result in the vehicle failing an emissions test. For this reason, if you suspect that your EVP sensor may be having an issue, have the vehicle inspected by a professional technician, such as one from YourMechanic, to determine if the issue should be replaced.


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Honorio

19 years of experience
828 reviews
Honorio
19 years of experience
Nissan Maxima - Oil Change - Campbell, California
He again was professional, kind and prompt! Definitely would recommend anyone who needs their car serviced to call Honorio!
Mazda 3 - Pre-purchase Car Inspection - Sunnyvale, California
Honorio was on time and helped us check out a car that we were thinking of purchasing. We are glad that we hired him! He did a diagnostic test using the OBD scan and checked all the fluids. It was clear from what he showed us that the owner had cleaned up the vehicle, but hadn't serviced the vehicle in over 5000 miles as all the major fluids were in need of replacement. After the test drive, he identified that there was a vibration coming from the driver side front wheel indicating an issue with suspension which could be at least another couple of hundred $. Really grateful for his professional knowledge and advice

Pedro

22 years of experience
26 reviews
Pedro
22 years of experience
Infiniti Q60 - Exhaust and Emission System - Woodland Hills, California
Very professional and honest. Was fortunate to have him be the one to show up. Thank you Pedro!

MICHAEL

33 years of experience
184 reviews
MICHAEL
33 years of experience
Mercury Mountaineer - Exhaust and Emission System - Philadelphia, Pennsylvania
Did everything he could to track down a emissions code, after all recommended to replace a bad PCM.

Aurelio

36 years of experience
35 reviews
Aurelio
36 years of experience
Jeep Liberty - Cooling/Radiator Fan Motor - San Antonio, Texas
Highly recommended. Aurelio was professional, polite, knowledgeable, honest, and communicative. Will definitely book him for services in the future. Thank you.

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