2007 Q7 4.2V8 sensor issues?
Thread Starter
|
1st Gear
Joined: Jan 2014
Posts: 1
2007 Q7 4.2V8 sensor issues?
I consider myself pretty handy and I like fixing things, but I’m not well-versed with engine mechanics particularly—I seem to know just enough to get myself into trouble. 
My wife has the 2007 Q7 with 4.2L V8 and about a month ago it began having trouble starting, but only after the engine had been run for about 30mins or so (she usually had time to run two or three local errands, pick up the kids from school, etc), and then when she would go to start it it would crank but wouldn’t fire. Oil and filter were recently changed (in October at the dealership) as well if that matters, though I will note that the engine has a slow oil leak and I’ve had to add 1.5qt of oil since Oct.
I drove the car myself for the past few weeks to see if I could figure out a bit more and pinpoint the issue a bit more specifically. I took it to AutoZone and asked them to pull any codes that were there (there was never a CEL on the dash, but I know that the light isn’t burned out because it displays when you first turn on the car). It seems that there was just one code, P0014. I’ve attached an image of the code readout below in case that helps:
IMAGE LINK: http://i708.photobucket.com/albums/w...codephoto.jpeg
A buddy of mine told me that this means that there is a possible error with one of the camshaft position sensor, specifically the one located on “Bank 1”, which after a little more research I found is the driver’s side bank of cylinders of the v8 engine. I found that there are 4 camshaft position sensors on this engine, two for each camshaft (because of the dual overhead cams I’m assuming), and I also assumed that because the code results readout above said “Exhaust (B)”, that I should look for a sensor closer to the exhaust manifold of the engine. I realize that all of this could be wrong as I’m pretty much self-taught (though very eager) on all of this so far, but to check it out I tried unplugging that sensor and the car was still able to start and run just fine, (albeit with the EPC and CEL lights on) but with the same issues as before (no start after engine heats up).
By the way, it takes about 30-60mins usually before the car will start again, sometimes less, sometimes more. But it definitely seems to be engine-heat related.
Then the other day the car began to stall while at idle speed (twice when backing up out of a parking space at idle in reverse, then once more at a red light). Fortunately the stall at the red light started right back up and I was able to limp home.
Other info:
1. The engine temperature gauge on the dash sits at right around halfway between the bottom and the top temps, center of the range.
2. The radiator temperature doesn’t seem to be out of range, and there is no blistering or swelling/bubbling of the reservoir or any of those components.
3. I don’t know where this very slight engine oil leak I have is coming from and haven’t yet investigated that further. I’m wondering if possibly it’s leaking onto the G28 sensor and causing it to fault out? The leak started after getting the oil changed at the dealership in October, possibly something was left slightly loose (filter, oil plug, etc?). Either way I’m wondering if that’s somehow related.
4. We’ve had the same key to the car so it doesn’t seem that the issue is related to that, though I’ve seen some issues posted with something called an immobilizer? We did, however, at the same time as the oil/filter change, have the key fob battery changed as it had just died.
5. I tried hooking up a jump pack (extra battery for jump starting in remote areas with nobody around) to see if more power would help the issue, but no change there. Just cranked faster/harder but still didn’t turn over.
6. Oh, the engine has 102,000 miles on it, not sure if that would contribute to any of this.
The car runs great otherwise, steady idle, lots of power (love this engine, I used to own the 2007 RS4 before I sold it when we had our 2nd child), starts right up (before this issue), etc.
Thx all, sorry this is long. It's my first post on a car forum. Hoping to get this thing fixed and NOT pay a boatload at the stealership!
My wife has the 2007 Q7 with 4.2L V8 and about a month ago it began having trouble starting, but only after the engine had been run for about 30mins or so (she usually had time to run two or three local errands, pick up the kids from school, etc), and then when she would go to start it it would crank but wouldn’t fire. Oil and filter were recently changed (in October at the dealership) as well if that matters, though I will note that the engine has a slow oil leak and I’ve had to add 1.5qt of oil since Oct.I drove the car myself for the past few weeks to see if I could figure out a bit more and pinpoint the issue a bit more specifically. I took it to AutoZone and asked them to pull any codes that were there (there was never a CEL on the dash, but I know that the light isn’t burned out because it displays when you first turn on the car). It seems that there was just one code, P0014. I’ve attached an image of the code readout below in case that helps:
IMAGE LINK: http://i708.photobucket.com/albums/w...codephoto.jpeg
A buddy of mine told me that this means that there is a possible error with one of the camshaft position sensor, specifically the one located on “Bank 1”, which after a little more research I found is the driver’s side bank of cylinders of the v8 engine. I found that there are 4 camshaft position sensors on this engine, two for each camshaft (because of the dual overhead cams I’m assuming), and I also assumed that because the code results readout above said “Exhaust (B)”, that I should look for a sensor closer to the exhaust manifold of the engine. I realize that all of this could be wrong as I’m pretty much self-taught (though very eager) on all of this so far, but to check it out I tried unplugging that sensor and the car was still able to start and run just fine, (albeit with the EPC and CEL lights on) but with the same issues as before (no start after engine heats up).
By the way, it takes about 30-60mins usually before the car will start again, sometimes less, sometimes more. But it definitely seems to be engine-heat related.
Then the other day the car began to stall while at idle speed (twice when backing up out of a parking space at idle in reverse, then once more at a red light). Fortunately the stall at the red light started right back up and I was able to limp home.
Other info:
1. The engine temperature gauge on the dash sits at right around halfway between the bottom and the top temps, center of the range.
2. The radiator temperature doesn’t seem to be out of range, and there is no blistering or swelling/bubbling of the reservoir or any of those components.
3. I don’t know where this very slight engine oil leak I have is coming from and haven’t yet investigated that further. I’m wondering if possibly it’s leaking onto the G28 sensor and causing it to fault out? The leak started after getting the oil changed at the dealership in October, possibly something was left slightly loose (filter, oil plug, etc?). Either way I’m wondering if that’s somehow related.
4. We’ve had the same key to the car so it doesn’t seem that the issue is related to that, though I’ve seen some issues posted with something called an immobilizer? We did, however, at the same time as the oil/filter change, have the key fob battery changed as it had just died.
5. I tried hooking up a jump pack (extra battery for jump starting in remote areas with nobody around) to see if more power would help the issue, but no change there. Just cranked faster/harder but still didn’t turn over.
6. Oh, the engine has 102,000 miles on it, not sure if that would contribute to any of this.
The car runs great otherwise, steady idle, lots of power (love this engine, I used to own the 2007 RS4 before I sold it when we had our 2nd child), starts right up (before this issue), etc.
Thx all, sorry this is long. It's my first post on a car forum. Hoping to get this thing fixed and NOT pay a boatload at the stealership!
Thread
Thread Starter
Forum
Replies
Last Post
