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

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: A/C won't turn off or lower from high

The most common cause of blower motor issues is the blower motor resistor, though usually it will only work on high speed and won't work on any other speeds. Because yours is blowing in high speed in all speed settings,...

Q: The car engine vibrates on and off when going slow. It gets better after accelerating and then starts again when slow.

Hi there. The description you have provided leads me to believe that the engine is experiencing misfires. This could be the result of high resistance in spark plug wires or low ignition coil output. This could also be the result...

Q: How do you operate the continuously variable transmission?

If your car is equipped with an automatic transmission rather than a stick shift, you actually have what’s called a continuously variable transmission, or CVT. These are a little different from conventional automatics. Here’s what drivers need to know: ...

Related articles

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...
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...