Code Scanner

I've had a service engine light on in my '97 K1500 since I bought it. I took it to AutoZone and had it scanned and the guy said it's an oxygen sensor code. I said which one and he said it didn't tell him that, just that it was an oxygen sensor. Well, there's like four of those sensors on my truck and I really don't want to spend the money to replace all four.

A guy I know over the weekend told me he had a scanner that would tell us exactly which one is bad. Is this the Tech 2 scanner? Or just a higher end OBD-II scanner? I would think AutoZone would have something fairly robust. Perhaps I'm wrong.

At any rate, input as alway is appreciated. I'm just wondering what the differences are between the scanners and why one can apparently pinpoint and one cannot.

More likely than not it did tell him which one, he just didn't know it. Each one has it's own code. Without looking up the code, there's no way to tell. P0420 & P0421 are downstream, B1 and B2 respectively. I think the upstreams are P0170 & P0171, but I'm really not too sure.

EVERY code has a number linked to it.

There are quite a few different codes for each oxygen sensor, no activity, heater circuit, and so on, but every code will tell the sensor-Bank 1 Sensor 1, Bank 1 Sensor 2, Bank 2 Sensor 1, Bank 2 Sensor 2 and if you have a 4.3 or 5.0 there is a Bank 1 Sensor 3 but no Bank 2 Sensor 2.

Then there are the lean/rich and catalyst efficiency codes that may be caused by a faulty sensor

The scanner used by AZ may be cheap, but it should give a code number that may lead to the sensor