EGR System P0401 - 000 - Insufficient Flow HELP PLEASE

[mattgriff88]

Hi All,

I am having a bit of a problem with my Golf Mk5 1.9 TDI BKC 105bhp 2005 plate.

I keep getting a Emissions work shop light appear and after running a scan it is coming up with 16785 - EGR System P0401 - 000 - Insufficient Flow.

If i clear the code i can drive the car for 100+ miles without the light coming back on.
The light will only come back on if i stop the car and switch the engine off and back on again and the drive for a couple of minutes.
It will then stay on until i clear the code again.

The EGR valve was replaced around 10 months a go as i was having a similar problem, The problem went away until recently i was having another problem with the engine under cooling, I drove the car around for about a month like this with the engine never reaching optimum temperature.
I finally changed the thermostat which solved the under cooling problem but the same day the emissions work shop light appeared and i been having the insufficient flow problem ever since.

I took the inlet manifold flap and the EGR valve off the weekend and it wasn't gunked up but give it a quick clean anyway.
I do smell exhaust fumes in the cab sometimes, Normally when i return to the car a few hours later after a long drive.

Someone suggested i remove the vacuum pipe from the EGR valve and block it to disable it, I done this but i am still having the exact same problem where i can drive the car for over 100 miles and the code will come back after i switched the engine off and back on again.

I have full access to VCDS through a friend, Is there anyway i can try and find out what is causing this through VCDS?

Any help much appreciated.

Here are 3 different scans after clearing the fault code each time.

16785 - EGR System
P0401 - 000 - Insufficient Flow
Freeze Frame:
RPM: 1827 /min
Torque: 30.0 Nm
Speed: 73.0 km/h
Load: 11.8 %
Duty Cycle: 14.7 %
Bin. Bits: 00101000
Mass Air / Rev.: 245.0 mg/str
Mass Air / Rev.: 575.0 mg/str


16785 - EGR System
P0401 - 000 - Insufficient Flow
Freeze Frame:
RPM: 1386 /min
Torque: 48.0 Nm
Speed: 31.0 km/h
Load: 13.7 %
Duty Cycle: 14.7 %
Bin. Bits: 00101000
Mass Air / Rev.: 225.0 mg/str
Mass Air / Rev.: 485.0 mg/str

16785 - EGR System
P0401 - 000 - Insufficient Flow
Freeze Frame:
RPM: 1848 /min
Torque: 66.0 Nm
Speed: 41.0 km/h
Load: 24.7 %
Duty Cycle: 14.7 %
Bin. Bits: 00001000
Mass Air / Rev.: 255.0 mg/str
Mass Air / Rev.: 625.0 mg/str

[Crasher]

For everyone else's benefit I will repeat what I put elsewhere

You mean over cooling. If you disconnect the EGR valve vacuum pipe you will get a low flow warning no matter what as you have shut the system down, it monitors itself and analyses the system flow to see it is working to its legally required standard. It may be that the vacuum solenoid block has an air leak which will prevent the valve opening and I have seen faulty Air Mass Meters cause this code but it is extremely difficult to test for a failed AMM, it tends to be a case of fit a new one and hope it cures it.

[omn]

Hi All,

I am having a bit of a problem with my Golf Mk5 1.9 TDI BKC 105bhp 2005 plate.

I keep getting a Emissions work shop light appear and after running a scan it is coming up with 16785 - EGR System P0401 - 000 - Insufficient Flow.

If i clear the code i can drive the car for 100+ miles without the light coming back on.
The light will only come back on if i stop the car and switch the engine off and back on again and the drive for a couple of minutes.
It will then stay on until i clear the code again.

The EGR valve was replaced around 10 months a go as i was having a similar problem, The problem went away until recently i was having another problem with the engine under cooling, I drove the car around for about a month like this with the engine never reaching optimum temperature.
I finally changed the thermostat which solved the under cooling problem but the same day the emissions work shop light appeared and i been having the insufficient flow problem ever since.

I took the inlet manifold flap and the EGR valve off the weekend and it wasn't gunked up but give it a quick clean anyway.
I do smell exhaust fumes in the cab sometimes, Normally when i return to the car a few hours later after a long drive.

Someone suggested i remove the vacuum pipe from the EGR valve and block it to disable it, I done this but i am still having the exact same problem where i can drive the car for over 100 miles and the code will come back after i switched the engine off and back on again.

I have full access to VCDS through a friend, Is there anyway i can try and find out what is causing this through VCDS?

Any help much appreciated.

Here are 3 different scans after clearing the fault code each time.

16785 - EGR System
P0401 - 000 - Insufficient Flow
Freeze Frame:
RPM: 1827 /min
Torque: 30.0 Nm
Speed: 73.0 km/h
Load: 11.8 %
Duty Cycle: 14.7 %
Bin. Bits: 00101000
Mass Air / Rev.: 245.0 mg/str
Mass Air / Rev.: 575.0 mg/str


16785 - EGR System
P0401 - 000 - Insufficient Flow
Freeze Frame:
RPM: 1386 /min
Torque: 48.0 Nm
Speed: 31.0 km/h
Load: 13.7 %
Duty Cycle: 14.7 %
Bin. Bits: 00101000
Mass Air / Rev.: 225.0 mg/str
Mass Air / Rev.: 485.0 mg/str

16785 - EGR System
P0401 - 000 - Insufficient Flow
Freeze Frame:
RPM: 1848 /min
Torque: 66.0 Nm
Speed: 41.0 km/h
Load: 24.7 %
Duty Cycle: 14.7 %
Bin. Bits: 00001000
Mass Air / Rev.: 255.0 mg/str
Mass Air / Rev.: 625.0 mg/str

Hi, were you able to solve this issue? I've the same problem, sometimes it smells exhaust inside the car. Not sure it if is the EGR valve or not.

Regards

[Crasher]

OMN, you will be better served starting your own new thread with the cars full details and the results of an engine ecu code scan

[mattgriff88]

Hi, were you able to solve this issue? I've the same problem, sometimes it smells exhaust inside the car. Not sure it if is the EGR valve or not.

Regards

Hi,

I changed the EGR valve again and it fixed the issue. I used the car for a further 6 months with no issues but then sold it.

The exhaust smell turned out to be a split fuel pipe that was going in to the fuel filter.

I also changed the pollem filter that is behind the glove box which was smelling of fumes.