CHEVY SONIC ENGINE LIGHT CODE
(As happened the first time he turned it off.) In researching info on the code and this car on other sites, I am not finding anything other than the steps that I described. I just think my mechanic is hesitant to start down the road of $250+ worth of dianostics and $600 of solenoids and sensors without more confidence that the check engine light will not come back on within an hour of leaving the shop when the car is seemingly performing perfectly at 60mph on the interstate. Neither has seen this and both are in agreement with both of you–likely evap system related. I have talked to two friends who are great garage mechanics. In posting this, I was hoping that someone might have seen this unique and distinct issue. But in any of these areas, we would expect to see constant performance problems, not just the one problem on starting the car after depressurizing (sort of), changing fuel volume and repressurizing the fuel system, as happens when adding fuel to the tank. Other possibilities include an evap cannister solenoid and a fuel tank pressure sensor, each minimum $300. If that is inconclusive, the next step he would suggest is a smoke test to try to find a vacuum leak (another $150 or more). The technical information recommends a MAP diagnostic (removing the sensor, cleaning, etc.)($125). The mechanic and I have discussed additional diagnostics. I can provide some additional information. Thank you for both (PureBred and Mustangman) for your input. I would appreciate any help you can give me. I haven’t found a good GMC dealer in my area. The independent shop mechanic said not to bother (honest guy! Or just afraid to dig into it). I don’t know whether to proceed to spend money trying to figure out the problem. The car runs and performs just fine except for a very tough start immediately after filling fully or partially with gas, when the car is mostly empty or only half or one-third empty, and all combinations thereof. He told me to drive it as is and try different amounts of gas when filling it and let him know if there are any other symptoms. He said he could replace a sensor in the evap system for the starting issue, but felt something else was wrong, and the check engine light would come back on. Again P0171, with P0324 (knocking, no surprise) and P0496 (evap system flow during non purge) also. The check engine light came on immediately. It did the same on the next fill–starting very rough (flooding). So he reset the code and had me go fill the tank with gas. The shop owner and I looked at the technical documentation for that code together, and my car had none of the symptoms described. It was P0171, which means fuel trim system lean.
I took it into the local shop who scanned the code for me for free. It started and ran well for the rest of the tank of gas. It ran very rough and knocked after filling the tank. I tried to start the car to leave the gas station, and it barely started. After about two weeks (I am now retired and don’t drive that much), I needed to fill up with gas. However, it ran absolutely fine, with no symptoms of anything wrong. Anyway, the car’s been pretty good, but the check engine light went on in July and did not go off with a new tank of gas, several starts and a new gas cap, as it had once before. I bought whatever was available for under $10,000, because State Farm did not compensate me fairly for the Sebring, of course. There was a snowstorm the next day, wrecking a lot of cars, so a ton of us were trying to buy a replacement car when inventories are low. It was 24 degrees when he hit me, 18 degrees when the tow truck finally arrived, and -10 when I started car shopping two days later. 12 totaled my Chrysler Sebring the second week of January, 2016. Before you groan, here is the story of why I bought it. It was Hertz Rent A Car that I purchased in 2016. I have a 2014 Chevy Sonic with 77,400 miles on it.