I have a friends 2011 Aveo, which had initial symptoms of it just died and they were able to jump it for a bit and then couldn't - this sounded like an alternator issue, and when we went to retrieve it from the side of the road, the battery (only about six months old) was at 11.8v, although it still started and ran. We put a fresh borrowed battery in it and were able to get it back home without a tow. DTCs present were (ECM) P0622 - Generator F terminal circuit and (TCM) P0562 - System low voltage. Both of which reinforce the failed/failing alternator diagnosis. After we got it back and I ran it some more, there was also t a(ECM) P0621 - Generator L Terminal circuit code. But then we went off the rails.
Upon giving it a once over, I found that there is what appears to be engine oil in the surge tank, there's an exhaust leak somewhere behind the engine that didn't register in my head when we got it running on the side of the road, and if I pull the dipstick while it's idling, it alters the idle, and if I remove the oil cap, it about dies. There seems to be a higher than normal vacuum in the crankcase.
I know at lest some here are versed in more than just the Duramax, so rather than going and finding an Aveo forum and posting as a noob, figured I'd start here and see if anyone might have any thoughts. The oil in the crankcase does not look like a milkshake, so it seems the crossover may be one way. I'm not sure if this little.... thing... has an oil cooler, but if it doesn't, the most likely crossover point would be the headgasket. Or something that's cracked. I'm basically thinking this may not be worth saving, but on the other hand, perhaps it's something stupid simple and cheap to fix (probably not, but hey, you never know). Does anyone here happen to have any experience with these little ****boxes or thoughts regarding possible causes?
Edit: found the exhaust leak, so that can be scratched off the question mark list.
Upon giving it a once over, I found that there is what appears to be engine oil in the surge tank, there's an exhaust leak somewhere behind the engine that didn't register in my head when we got it running on the side of the road, and if I pull the dipstick while it's idling, it alters the idle, and if I remove the oil cap, it about dies. There seems to be a higher than normal vacuum in the crankcase.
I know at lest some here are versed in more than just the Duramax, so rather than going and finding an Aveo forum and posting as a noob, figured I'd start here and see if anyone might have any thoughts. The oil in the crankcase does not look like a milkshake, so it seems the crossover may be one way. I'm not sure if this little.... thing... has an oil cooler, but if it doesn't, the most likely crossover point would be the headgasket. Or something that's cracked. I'm basically thinking this may not be worth saving, but on the other hand, perhaps it's something stupid simple and cheap to fix (probably not, but hey, you never know). Does anyone here happen to have any experience with these little ****boxes or thoughts regarding possible causes?
Edit: found the exhaust leak, so that can be scratched off the question mark list.
Last edited:
