How do you clear a "check engine light"

Maintenance/Repairs
1

After changing sparkplugs and fuel filter my check engine light came on. Local parts store scanned and it’s “lean fuel”. I’ve checked all vacuum hoses, all bolts, clamps, air handling system etc. How can I clear to see if problem is fixed? Also, could dirty fuel injectors cause this error to appear?

2

Disconnect the positive battery cable and wait ten minutes or longer before reconnecting it.

3

I think you mean the negative battery cable.

4

Well, you can buy a cheap code scanner. OBD2 Scanners not only read codes, they can clear them. Autozone has a scanner that should be adequate on sale this month for $60.

Or you can take it to AutoZone and ask them to clear the codes which they will probably do as a courtesy.

Or you can disconnect the battery. It really and genuinely doesn’t matter which battery cable you disconnect. The Negative terminal is usually specified so that if your wrench slips and comes in contact with a chassis part you don’t have a huge spark, loud bang, and a big voltage transient wandering through the electrical system. But from a pure reset the ECM, disconnecting the positive terminal should work as well if you can do it safely.

If you have a vehicle wiring diagram and can read it, you can look and see if the ECM (the computer that handles the CEL) is on a fused circuit. If so, you can remove the fuse for a minute or two. Finding the fuse (if there is one) is not always a slam dunk. In my limited experience, the wiring diagram will tell you that there is an X amp fuse but not what it will be called. The fuse diagram will label the fuses by the major component on the circuit. On our 99 Camry, the ECM fuse is labelled EFI. On our 95 Neon, it’s the fuel pump fuse. On our 2002 Protege, there doesn’t seem to be a fuse. But I’m still hoping that I’m not reading the diagram right.

There’s also a fair chance that the code will clear on its own if you have actually fixed the problem. Many conditions take a couple of dozen starts or ‘drive cycles’ (not the same thing as starts) without a problem before they will clear. If the car runs OK, I suppose that procrastination is an option. But personally driving around for too long with the CEL lit makes me nervous.