Skip the auto shop - Our mechanics make house calls

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?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  • Home
  • Questions
  • 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: Gages won't move and car needs a jump to start.

Hi there: The problem with electrical issues is that without being there to diagnose the problem, it's hard to tell you exactly what's wrong. Some of the common reasons why your car won't start based on the symptoms you've described...

Q: My fuel pump won't turn on. On my 95 Pontiac firebird

Hi There, I would suggest checking the ground connections and wiring to be sure there is proper connectivity. This is something that is very easy to overlook and can cause problems with getting the fuel pump to come on when...

Q: What exactly does the code P3fff mean?

Hi there. The code P3fff means that there is an issue with the PCM (the computer to the vehicle). The codes regarding gas recirculation flow and mass air flow are coming on either due to the PCM failure or due...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
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...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...