You are driving down the road, all is well with the world and suddenly your check engine light (CEL) comes on. Fear and anger rise up along with a few choice words. You start to wonder, how much is this going to cost? Am I in danger of ruining the car if I keep driving? What do I do now?
Maybe you drive to your friendly neighborhood auto parts store for a “free scan”. Many times, the verdict will be a few codes that appear to be meaningless and the offending part will usually be an O2 (Oxygen Sensor) or some other “emissions” related item.
The truth is that although there very well may be a code or fault for the oxygen sensor, it is likely caused by something causing the car to run either rich or lean (too much fuel, not enough air or the other way around). This usually happens before the oxygen sensor, but that is where the issue is reported. Those pesky sensors are always sniffing the air after the combustion has happened and have certain parameters that need to be met based on all sorts of criteria.
In our earlier example, we will have clients call and ask, “How much for an O2 sensor for my car?” If we simply gave a quote, it was agreed on, then installed, and the check engine light was still on, the client would likely be upset. This is why we must perform a diagnosis, to identify the root cause of the check engine light (CEL) and offer options for repair rather than simply swapping parts and hoping.
