Q: I had a p0405 get code replaced egr valve, map sensor,mad sensor, and PCv valve just to be safe but still getting the code why?

asked by on

I had a code pop up for egr system p0405 the I also had a mass air flow code. To be on the safe side I ordered all brand new parts with a few extras to be safe as following. The egr valve components, the maf sensor, a map sensor, and a PCv valve installed and reflashed codes car runs good now no hesitation or stumbling whatsoever. But when I turn it on it still lopes and idles at a low rpm 500 or so. What do u guys think it might be? I also keep on getting the p0405 and already checked voltage and it is good

My car has 170000 miles.
My car has an automatic transmission.

The code P0405 and a rough idle is most likely due to carbon getting into the EGR pintle. This will hold the EGR open. When you are getting the rough idle you should shut off engine and remove EGR valve. Check to see if carbon is holding the pintle open. If it is then you will have to remove the carbon from the pintle. Then try and clean out the EGR passages by scrapping them using a round wire brush. Afterwards, start the engine for a few seconds with valve removed to blow out loose carbon. You should then spray a small amount of carbon cleaner into the passages to dissolve the carbon. Lastly, reinstall the EGR and reset the light and codes.

If you’d like assistance with this, consider YourMechanic, as a certified professional can come to the vehicles locations to perform these checks and properly diagnose your Check Engine Light.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. I had a p0405 get code replaced egr valve, map sensor,mad sensor, and PCv valve just to be safe but still getting the code why?

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Smashed Car Door

I would recommend to call around to your local body shops to ask for quotes on the repair that is necessary. Based on the sound of the damage, the repair will likely involve replacing the door in order to get...

Q: The car cranks a lot, turns off while idling, gas smell in the car

You need to have the fuel injection checked to see if the system has a fuel injection leak or a pressure regulator leaking. The fuel system, including the filter and pump lines, needs checking to see why you are smelling...

Q: New car that is always lighting up ‘check engine’

Hello, thanks for writing in about this issue. No, your car is not a lemon! The Check Engine Light (CEL) is trigged by the engine control unit when it detects a fault with any engine sensor or a...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...