Subaru Legacy GT Wagon, My Dear Check Engine Light
By Mike Garcia
See the cover shot? That’s me driving at an appropriate speed, assuming the speedometer has a possible 10% margin for error, on the freeway. At the lower left hand corner, there is a stuck light. It is one that most people on the road fear most, the dreaded check engine light. What you don’t see is a blinking cruise control light and an intermittent airbag light. Most owners would panic. I don’t.
When I bought the car, it had the check engine light. I’ve been a car guy my entire life and even went to automotive school just to learn about them, though, I’m not a technician. I knew enough to feel comfortable with the check engine light to get it fixed later. After all, it drove perfectly fine.
I’ve taken it to the shop a couple times with a reputable Subaru specialist. After the first time, the check engine light reappeared after 50 miles. After the second time, it appeared after 30 miles. I’m not really all that mad. I tend to think of automotive repair as a team effort. I give you the best information I can give you, you do your best to diagnose and repair.
I think that’s fair.
Well, I took my car to a friend’s house today. He too, is a Subaru owner. Unlike me, he owns an Impreza WRX STi. If I remember right, it’s a 2009 model. Lucky him.
He plugged in his OBD II scanner. It pulled the same PO171 code. He connected his lap top to it. We took it for a short run. A few things we noted.
1. The MAF was reading at a high level, 3.2g/in.
2. Air/Fuel ratio was right around the ballpark under load.
3. My car was 16* in advance. I’m pretty sure that has to do with the Techron fuel cleaner I put in it yesterday.
I had a full tank of Chevron gas and the car felt perfectly fine.
Needless to say, I am reasonably comfortable driving it on a daily basis. I notice slightly late shifts from the transmission, but the engine overall doesn’t have as much pep. The ECU is dumping gas to get the air/fuel ratio right, at the cost of horsepower and gas mileage.
I’m okay with it. The car still gets 20 miles per gallon on the average.
Still, it’s only a matter of time before I bring it to the same shop. This time, I’m bringing additional information during the test drive.
I may be okay with a check engine light, but it doesn’t mean I’m that comfortable with it. It it was running well, the light wouldn’t appear anyway.