One more Check Engine Light question

I think so. The price differences, at least as they relate to a late '90s car, are primarily feature and convenience matters. More expensive ones usually display the english meaning of the codes while (in general) less expensive ones show the code and provide a book to look up the code. I took the middle ground and bought one for about $170 US that offers periodic code deciphering updates. For your car the newer CAN versions don't offer any benefit.

They really are nice things to carry in the trunk on trips, so if the "something's wrong but I won't tell you what it is" light comes on you can see what's up, and either deal with it - like tighten the gas cap - and reset the code or know why.

The readers will also tell you about "pending" codes - disturbances that are beginning to annoy the ECU but aren't hard failures. In the case of your mystery light, that could be helpful. If the codes start to come back under only certain conditions, like acceleration, idle, cold or warm situations, whatever... those would be good clues.

Mike

Yes a scanner/reader is a very handy thing to have. They will also work on any '96-later OBDII vehicle not just Subaru, so if you have more than one car it's even more useful. I'd suggest staying away from the cheap ones though. Check out the Code Scout from AutoXray at

Some auto parts stores (national types) offer FREE CHECK ENGINE CODE service.. ...

Autozone is the only one I know that does it for free. But it's much more convenient to have your own scanner so you can do it yourself. Also the scanner can provide you with the information you need to actually track down the problem that caused the light to come on.

I'm glad both options are available. I have only used mine a few times, but then I only have one car it works on... the other three in the family are pre-96. I've also heard the Autozone service isn't available in Silicon Valley - anybody confirm or debunk that?

Mike

I had the same thought. I took the car in today, and it keeps coming up as the throttle position sensor (they drove it around hooked up), so they are going to install a new one, no charge for labor.

I figure if I'm out in the middle of nowhere and the light comes on at least I can get a code and know whether the car needs a tow or I can keep going. I've heard stories about people driving for years with their light on, and others who's engines blew up shortly after the light came on.

My mechanic wishes that they would make the light so when the failure is critical the light glowed red instead of orange. That would be nice. He seems to spend most of his days diagnosing Check Engine lights on newer cars.

From what I understand they do not do the free scans in CA. Something about the shops getting upset or whatever. They may allow you to do it yourself by leaving a deposit and borrowing the scanner then bringing it back when you're done. I'd suggest calling or stopping by a local Autozone to get the official answer.

Normally, the "check engine" light is only related to emissions systems and doesn't herald anything so wrong you can't drive the car. Sometimes it will be things like VSS failure, which can cause some cars to stick in low gear, but more often the light is there to say you have an otherwise symptomless failure that is causing you to pollute.

An exception is anything that causes the engine to run very rich - the catalytic converter can be damaged by the excess heat. Still, the car can be driven normally in town and gently on the highway with the "gently" restriction lifted when the fuel economy is found to be normal.

Mike