hman_a4

- Gas cap not closed fully. Let it click a few times -- it is impossible to close it too tight.
- Dipstick not all the way in
- Letting gas tank run bone dry -- or get very close
- Adding gas with the engine running [believe it or not, some people do that!]

Again, if the light is NOT flashing, check the above and it give it a couple of days. After that, take it in!


2001 A4 2.8Qtscbx

shv2.7T

Came on at 25000 miles shortly after routine service and recall replacement of fuel sending unit. Went off in one day only to return; dealer replaced faulty O2 sensor per code, now fine. Newly installed fule sending unit faulty(original issue worked fine)- also corrected.

vta6

1998 A6 with 105,000 miles. This morning car started but running very rough. Engine light blinking. Very very cold night -30. The night before, I put in the garage. Ran fine the next data. My wife's Jeep got the spot last night. Do I need a new coil Pack, one of the plugs foil? What should I expect from the dealer? Thxs. for the help,

ga1830

I have the same problem too recently. Due to recent rocketing gas price, I had a couple of times putting cheaper regular fuel. The light started on about 10 days ago. I took it to my garage and had the code reset. At the same time I had the A4 3.2 refilled with 93 ultra gas. But 4 days later, the light came back. Again code was reset. Unfortunately the light was on again today (exactly 4 days cycle). Any clue?

ga1830

I have the same problem too recently. Due to recent rocketing gas price, I had a couple of times putting cheaper regular fuel. The light started on about 10 days ago. I took it to my garage and had the code reset. At the same time I had the A4 3.2 refilled with 93 ultra gas. But 4 days later, the light came back. Again code was reset. Unfortunately the light was on again today (exactly 4 days cycle). Any clue?

chrisgerolmo

I have a 2002 Audi S6 Avant and the check engine light comes on constantly. It's always P0442 - EVAP minor leak detected. As per my mechanic, "Purge valve and gas gap have been replaced. Smoke check has not revealed any leaks." I'm stumped. Does anyone have any ideas?

tester123

1) Ensure the Evap purge valve (I think... N80) is working. Yes, the mechanic said... Check it for yourself. It should be making a "clicking" noise when engine is running.

2) The gas cap seal is next best place. I had this issue for long time... so, I just order OEM gas cap gasket (~$12.00 each) sure beats buying a new cap. I have to replace this every 2 or more years... Never bothered to "figure" out a permanent fix with the gas cap situation. After few restarts during normal driving, the light goes away on mine. So, there is that.

3) If these don't solve your problem, time to dig deep tracing the evap purge line all the way to Gas tank leak detection pump and charcoal canister and gas tank itself to find the "leak".

If you have vag-com, you could run diagnostic on leak detection pump and see if it is holding.

Harleyguy

If purge valve and cap have been replaced, try a hard reset before spending more money. Disconnect battery for a while and then hook it back up. This will sometimes reset fault warnings and codes. Not always but worth a shot. Vacuum leaks can also be a cause but should throw a code. Secondary air pump can also cause the CEL. If hard reset doesn't work, have the mechanic pull codes. He/she should have done that after doing the repair to be sure it was corrected.

Fernando flores jr

[QUOTE=Wowdi;14685395]- Make sure gas cap is tight securing it with at least three "clicks".

- Wait for about five days for the Check Engine light to go out.

- Bring the car in for service if the light stays on.

My light went out but would come back on after a few days. The dealer gave me a hard time about admitting that it was a hardware failure. I bought VAG-COM to read the malfunction codes to verify that it was an O2 sensor glitch and took a screen print to the dealer. It turned out the my O2 sensor was indeed bad and had to be replaced. No problem since then. Left me frustrated with my dealer.[