Man I just bought a 96 a4 2.8l the other day and then the next day the CEL light came on.. I went to autozone to check it out they said somthing about a EGR valve and gave me a troubleshooting number of P0401 saying somthing like there is insufficient flow in the exhaust gas recirculation system. But everything been running okay...should i worry about this? What should I do? I read another post the other day saying that if you pump ur gas while the car is on that could also happen? is that true or could that be the case? can somone help.....Thanks for the Help

 

had the same on my 96 a6. had the cel cleared and has not yet come back. the egr valve, exhaust gas recirculation valve, the vacum lines could be cracked, the valve itself can get fouled with carbon an need a cleaning. it is an expensive part, no matter where online you look. if you do a search on the forum you will find the postings and replies i made when inquiring.

 

01-76


Output on GST and/or on VAG 1551 scan tool
Possible malfunction cause

Malfunction repair

P0401 / 16785

Exhaust Gas Recirculation Flow Insufficient Detected
EGR system vacuum hose kinked or fallen off

- Check vacuum hoses




Malfunction cause found: Yes

No

- Erase DTC memory, test drive and after test drive, check DTC memory again

MIL Status:

MIL lights up after 2 Trips
Leak in a vacuum hose of the EGR system (e.g. cracked, worn though, etc.)

- Check vacuum hoses for leaks




Malfunction cause found: Yes

No

- Erase DTC memory, test drive and after test drive, check DTC memory again




Vacuum hose between EGR vacuum regulator solenoid valve -N18- and mechanical EGR valve plugged

- Check vacuum hoses for obstructions



For troubleshooting Display group 017
Malfunction cause found: Yes

No

Continued next page

- Erase DTC memory, test drive and after test drive, check DTC memory again





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01-77





EGR vacuum regulator solenoid valve -N18- sticks in closed position

- Check EGR vacuum regulator solenoid valve -N18- page 24-67


Malfunction cause found: Yes

No

- Erase DTC memory, test drive and after test drive, check DTC memory again




EGR valve sticks in closed position

- Check mechanical EGR valve page 24-70




Malfunction cause found: Yes



- Erase DTC memory, test drive and after test drive, check DTC memory again

 

i have the same thing on my car...how do iclean the egr valve?

 

what MIL and DTC memory stands for??

 

These are for 12 valves:

http://forums.audiworld.com/9080/msgs/84474.phtml

http://forums.audiworld.com/a6100/msgs/4003.phtml

 

thanks