P0401 caused by Aftermarket exhaust?

[Crazyhorse]

At least that's what the dealership is telling me now, since they can't find a problem. For 90,000 miles the truck ran perfect, and never threw a code with the MBRP duals with cat delete. At 90K it went in for the mandatory (by the state of California) 06E17 recall and got the latest flash. It has now been in 5 (maybe 6) times since then for a variety of issues (lost of power, loss of fuel economy, higher EGT's, higher trans temps and a boiling sound when you lift out of the throttle). The only code that keeps coming up is P0401. They cleaned the valve, then replaced it the next time, and are now telling me that everything is normal, and that the exhaust is causing all of my problems, but they can't answer as to why it never had the problems before the reflash (it's a coincidince according to them).

Is this a code that can be triggered by free flowing exhaust, or are they blowing smoke?

 

[bushpilot]

thats funny...

P0401 - EGR Flow INSUFFICENT

 

[DaveBen]

The EGR cooler may be plugged or restricted.

Dave

 

[DaveBen]

I looked it up on my Service DVD and the EGR Sensor may be faulty.

Dave

 

[Crazyhorse]

Is the sensor part of the valve, or seperate? The valve was replaced in august when it threw this code (after the old valve was cleaned in July for this code being thrown)

 

[bushpilot]

obviously the problem ISNT the EGR valve...if cleaning and replacing it
didnt solve the problem then something ELSE is causeing the codes to be
"thrown".

I would be looking at the supporting plumbing...including the egr cooler
itself...and the flow THRU the egr cooler.

Page 58: Electrical Components

Page 32: Air Management System
Page 55: Electrical Components
Page 37: Air Management System
Page 38: Air Management System

 

[DaveBen]

The sensor is located on the drivers side of the engine, at the front, with a small pipe going down to the exhaust manifold. It is on the front portion of the head.

Dave

 

[Fandini]

I've been looking at the exact exaust system, wonder if I should just get a cat back system? Seems like these dealers will blame anything on aftermarket parts. Seems kinda like a big pile of something really smelly.

 

[bushpilot]

well thats pretty much how it works...when they cant fix it or figure out
whats REALLY wrong they start lookin' for excuses !

 

[bushpilot]

The sensor is located on the drivers side of the engine, at the front, with a small pipe going down to the exhaust manifold. It is on the front portion of the head.

Dave

FWIW Dave is talkin' 'bout the EBP (exhaust back pressure) sensor,
Page 58 (of the bible) linke above.

the EBP is #3 three in the front/left view at the following link:
Page 9: Component Locations