Need help: Replace EGR Solenoid


Registered User
Hi all

I have the below DTC and I have already removed and cleaned the EGR valve. I have spoken to Audi and they think its either the vacuum pipes to the EGR valve that need cleaning or the EGR Solenoid is faulty. I think the vacuum pipes are ok as when i disconnect this from the EGR valve and press the accelerator I can feel a good suction coming through so it must be sucking on the EGR valve correclty. Does anyone know a "how to" for locating and replacing the EGR Solenoid?

I have used VAG com "measuring blocks" to monitor the MAF and also the Duty Cycle which I believe is of the EGR Solenoid and it is mostly 15.1. It spikes up to higher values but normally returns to this value. There are also significant differences between MAF requested and actual. I have attached a screen shot of the output at idle. Can someone please advise me on this? If there is anyone with a little spare time and with VAG COM could you please run the "measuring blocks" feature to monitor group 003 and see what it says for a system with no MIL or EGR error specifically at idle? Is the duty cycle supposed to be between 40 and 75%?

16785 - EGR System: Insufficient Flow
P0401 - 000 - -
Freeze Frame:
RPM: 1848 /min
Torque: 68.0 Nm
Speed: 47.0 km/h
Load: 24.7 %
Duty Cycle: 14.7 %
Bin. Bits: 11000000
Mass Air / Rev.: 365.0 mg/str
Mass Air / Rev.: 610.0 mg/str

I would really appreciate some expert advice on this one.

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