I just purchased a 2007 Subaru Legacy GT with about 140k miles on it. It has been driving just fine for 2 days, but I decided to fuel up with mid grade gas instead of the recommended premium, and now the check engine light is of with the flashing green cruise light. Could the mid grade gas cause this? The engine still sounds fine and I don‘t see any other problems.
The CEL light is always related to an emissions control problem. Some car's computers also trigger the light for non-emissions issues. The wrong gas won't affect the CEL light. Since you imply that the light came on after you filled up, I would first look at the gas cap to ensure it is properly seated. Also, if you overfill the tank, the vent and purge systems will cause a code to be set. The liquid gas will block the purge lines. Take the car to an auto parts store. Some will scan your code for free in hopes of selling you a needed part. In my internet search, it seems that the CEL causes the green cruise light to flash, probably in an effort to draw your attention to the dash panel and the CEL light. If you fix the cause of the CEL problem, you'll probably fix the cruise light flashing problem also.
MOSt times te4h REAL cause of an ENGINE LIGHT is a dirty IDLE AIR CONTROL VAVLE and THROTTLE BODY. THese thigns FINE tuen the incoming AIR portion of the FI system. NO GAS additves will GET THERE. THese things must be MANUALLY cleaned out. TAke $20-30 to the local quicky lube and have them clean BOTH items to SHOWROOM clean. Your will just DISPAPPEAR! The other REAL cause is using VERY CHEAP engien oil that makes LOTS of sludge and acidic vapros. This is WHY scienteists invented SYNTHETIC OILS. They keep engine sCLEAN and th eoil lasts 3-4 times LONGER without makding SLUDGE AND VARNISH. BAD oil will reeuce expensvie engin sensors to crap in a short time. ALWAYS leep your IACV and T body PERFECTLY CLEAN! GOOD LUCK!!
First off will someone else report Sean so they will throw him off answers. The grade of fuel will not make a big difference and will not turn the engine light on nor would the light come on if you need a oil change. It will come on if you didn't put the fuel cap on tight. It would be best to have the code read at a auto parts store that does that for free, then you will at least know what the code is for.
