Skip the auto shop - Our mechanics make house calls

Q: Code P0400; EGR System

asked by on

The code on my Nissan Altima is only the P0400 code. However, I have cleaned out the valve and when I suck on the vacuum tube, the piston moves up and down inside the valve. None of the hoses are damaged. I had all my hoses and pipes replaces after an oil leakage to ensure none of them would be disintegrated by the residue. I am trying to narrow down what I need fixed, hopefully without needing to pay a diagnostics fee. From the research I have done if the EGRC Solenoid Valve was needing to be replaced I would have a P1400 code, however, I only have the P0400 code. The other possible part that would need to be repaired would be the temperature sensor. Yet, this seems to be infrequent for this issue.What part do I need to replace? Is my EGR valve working properly if the piston inside still moves up and down when I suck on it?

My car has 266500 miles.
My car has an automatic transmission.

If you checked the EGR valve and cleaned it, the first thing to do is to start and idle the engine and use a vacuum pump or source to pull open the EGR valve to see if it makes the engine run rough.

It should cause the engine to run rough if the passages are clear. In the EGR tube there is a temperature sensor that can be removed and cleaned of carbon. If it has carbon build up, it can cause inaccurate EGR readings and code P0400. Run engine warm and at around 2000 RPM’s and see if EGR is being opened by the EGRC or there is vacuum on the hose to the EGR valve. Check the purge valve to see if it’s leaking vapor all of the time.

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

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Code P0400; EGR System

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: Instruments and radio going on and off in car

It sounds like you may have an alternator issue. Many times when alternators go bad they can affect other electrical systems of the vehicle since the alternator is tied in with the electrical system. My first recommendation would be to...

Q: would like to speak to mechanic Pardeep

Hi Richard. Thanks for sending in the question today. I have forwarded your inquiry to our sales and service department. They'll have to look up your information and appointment to get ahold of the notes and follow through with your...

Q: How does the automatic moon roof work?

moon roofs are great – they let in light and air, and they make your car feel larger than it is. Your car’s moon roof offers simple operation, but there are a few things you need to know before you...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...