EGR: Excessive Flow 16786/P0402

To DIe for

Veteran Member
Joined
Apr 23, 2006
Location
San Leandro, CA and SF East Bay
TDI
02 Jetta
Got an excessive flow code last weekend. Some research on the forum has revealed this to be a common problem with an uncommon solution.

Heres what RossTech says: http://wiki.ross-tech.com/index.php/16786/P0402/001026

Logically thinking, overflow means the valve is stuck open? I manually tested the shudder and it flows freely. I also tried applying vacuum pressure to the shudder and it closed as well. Next in line is the EGR vacuum solenoid. I suspect this is the culprit. Can anyone here chime in? I suppose it could be a vacuum leak, which I partially ruled out. It could also be the n18 or the n75.

Also, if the code is being thrown, that means a sensor is picking up too much gas, but im not sure which one. The MAF?

-Carl
 

streeker02

Veteran Member
Joined
May 12, 2008
Location
Halton Hills
TDI
2003 Golf TDI
To DIe for said:
Got an excessive flow code last weekend. Some research on the forum has revealed this to be a common problem with an uncommon solution.

Heres what RossTech says: http://wiki.ross-tech.com/index.php/16786/P0402/001026

Logically thinking, overflow means the valve is stuck open? I manually tested the shudder and it flows freely. I also tried applying vacuum pressure to the shudder and it closed as well. Next in line is the EGR vacuum solenoid. I suspect this is the culprit. Can anyone here chime in? I suppose it could be a vacuum leak, which I partially ruled out. It could also be the n18 or the n75.

Also, if the code is being thrown, that means a sensor is picking up too much gas, but im not sure which one. The MAF?

-Carl
How's your intake? Although the code says excessive flow, I have seen clogged intake/egr throw this code.
 

PDJetta

Top Post Dawg
Joined
Nov 6, 2003
Location
Northern Virginia
TDI
'04 Jetta GLS TDI Pumpe Duce Platinum Grey w/ Leather
Yea, I think the code description on the pre-pumpe duse TDIs (the ALH)may be backwards for the EGR, because the mass air flow sensor measures "excess (air) flow" through it when the EGR gas flow is too low, since an increase in exhaust gas flow into the intake slows down the air flow into the intake. For my '04 PD, the code is simply, "Insufficient EGR flow".

In addition to looking for a clogged intake, look for a clogged EGR cooler tubes as well. On the ALH engine you can remove both EGR pipes from the cooler and rod out the cooler with a coat hanger wire and blow the crud out with compressed air. Use the old gaskets again. They will seal fine.

How is the EGR valve diaphragm? Does it hold vacuum? Vacuum source to the EGR valve, is it OK?

--Nate
 
Last edited:

To DIe for

Veteran Member
Joined
Apr 23, 2006
Location
San Leandro, CA and SF East Bay
TDI
02 Jetta
I have yet to check for blockages in the manifold and hoses, but last time I checked they were fine.

Also, I think I remember hooking the mityvac up to the diaphragm and I dont think it help vacuum. I should check again, but if that the case, am I looking at a new EGR?

-Carl
 

jcrews

Top Post Dawg
Joined
Jul 28, 2007
Location
Round Rock, TX - VCDS
TDI
All gone
Read MB 003 and see what it says. Use basic settings (same group) to cycle the EGR. Observe the result and see what's going on. You may have to jam the accelerator if you let it idle too long (EGR goes off).
 

To DIe for

Veteran Member
Joined
Apr 23, 2006
Location
San Leandro, CA and SF East Bay
TDI
02 Jetta
Well, after much speculation, it turned out my problem wasn't the MAF after all. I suspected the EGR solenoid from the very beginning because my valve was holding vacuum and the solenoid was the next part in the loop. I tried to see if the valve would hold vacuum in a variety of tests and I couldnt get it to, so I started there. $40 bucks later, I replaced the valve and fixed the problem! Feels good to fix your own problems! I also noticed the car doesnt shutter as much when shut down.

Thanks for the help gentlemen.

-Carl



Edit: The part was a bit hard to track down though, so, if any members need the part number, or location of where it may be bought, PM me.
 
Top