larrycr

I have a 2015 Q7 Prestige with the 3.0T engine. Purchased earlier this year and it now has about 8,000 miles on it after two trips to Colorado (we’re there now) and an east coast loop that included North Carolina and Virginia. Our home base is eastern Iowa.

In Colorado we’re staying near Estes Park at about 8,500 feet and make frequent drives into Rocky Mountain National Park to an altitude of about 9,500 feet. On our June trip we took two drives to the 12,000 foot level.
A few days after arriving in Estes Park on this trip the Q7 lit up its MIL (check engine). The light was on steady so I got an appointment with an Audi dealer in Boulder and took it in a few days later. During the time the light was on I drove about 70 miles, then drove the 40 miles to Boulder. The light was on the entire time, but when I got to Boulder it had gone out. I’m not sure when it went out, but it was on when I left Estes Park and it was off when the service guy started it up. Boulder’s altitude is about 5,400 feet.

The dealership indicated the fault showed an evap system leak. They tested and found the system to have no leaks. I had NOT left the gas cap off.

Drove back to Estes Park and continued driving into the mountains every day. A little less than two weeks later and the MIL is on steady again. I assume it is the same failure. I had filled up with gas at least a week earlier and the gas cap is firmly in place. We’re headed back to Iowa soon. It will be interesting to see if the indicator goes out again when we reach a lower altitude.

Maybe a leak somewhere that the dealer’s test doesn’t look at?

Edd W

If it comes back on, see what happens if you release any residual pressure in the fuel tank by loosening the filler cap then tightening it again.

larrycr

I gave it a try but it didn't put out the MIL. Took the cap off, put it back on, and tightened it firmly. After a couple of short drive the lamp is still indicating a malfunction.

smith2010Q7

Since your Q7 is still under warranty have them give you a new fuel cap. It is cheap and we can check off one item bad or not.

larrycr

I'll suggest that when I take it in to my home dealer next week. Thanks.

larrycr

Made it back to Iowa and the CEL stayed on the whole way. I scheduled an appointment at my dealer for yesterday. The day before I filled the car up (for the second time since Colorado) and the next morning the CEL was off.

Dealer diagnosed a sticky switch in the leak detection pump. They replaced the pump and switch assembly this morning. So far so good. We'll see what happens when I head back to the mountains.

smith2010Q7

Looks like you have a good Audi team.

larrycr

They (Carousel Audi in Iowa City) have been servicing my cars for 20 years. They have a perfect track record with me.