Your timing chain could have jumped. Your gas cap seals the fuel system and maintains system pressure and leaking fuel vapors can cause the whole system to go haywire. Therefore, this warning light should be properly diagnosed to pinpoint the exact problem. Most owners will take their car to a repair shop and have it hooked up … Second major issue in two months. Car alert says issue with emissions system has been detected. always comes up an evap code that gas cap is loose. It is never a good idea simply to assume that the "Check Engine" light is on because the gas cap is loose. If you have VVT, it may be having issues. The most recently reported issues are listed below. If the light is flashing, take your vehicle in IMMEDIATELY to be diagnosed and inspected--a flashing light indicates a serious problem with one of your vehicle's components. Oftentimes if the gas cap wasn't tightened enough, the check engine light will display. Once … Average failure mileage is 48,400 miles. Also please check out the statistics and reliability analysis of Chevrolet Sonic based on all problems reported for the Sonic. An illuminated Check Engine Light is another symptom of a potential issue with the vehicle’s gas cap. Please also check out the statistics and reliability analysis of the 2013 Chevrolet Sonic based on all problems reported for the 2013 Sonic. Other Issues: Flashing Check Engine Light- Chevy Sonic. Four problems related to check engine light on have been reported for the 2013 Chevrolet Sonic. (RockAuto.com is a MotorWeek Sponsor) A leaky fuel tank cap may be responsible for a lit Check Engine light. While a majority of the time, the flashing check engine light is going to be caused by a misfire related to your Sonic’s ignition system or fuel system (as stated above), there are other issues that can cause it. 2016 chevy sonic. Chevrolet Sonic Gas Cap Customer Reviews. First it was the AC. The gas cap is a part of the vehicle’s evaporative emissions system and can cause problems with the system if it has an issue. The 2012 Chevrolet Sonic has 10 problems reported for check engine light on. Dealer claims not covered and I would have to pay diagnostic fee to determine issue. The most recently reported issues are listed below. You Might Have a Loose or Faulty Gas Cap If that dreaded check engine light comes on, the first thing you should check for is a loose or faulty gas cap. Car been to subaru shop 4 times in 6 weeks for this. Trying to figure out issue no other codes come up … If the light is not flashing, check the gas cap. I have a 2012 chevy sonic 1.8 engine. Check your gas cap to ensure it is tight and intact. Car runs smoothly tho. Average repair cost is $110 at 41,800 miles. Tyler Williams. Chevrolet Sonic owners have reported 20 problems related to check engine light on (under the engine and engine cooling category). check engine light came on. It's a gas cap.. Did not turn off my engine light problem as others stated. The 2014 Chevrolet Sonic has 3 problems reported for engine light on. I had purge valve replaced twice and check engine light still came back on.