"The Constitution is not an instrument for the government to restrain the people, it is an instrument for the people to restrain the government."
-Patrick Henry
A5150nut
2006 K3500 D/A
94 6.5 4x4 5spd Sold
Nope. No KOKO. That went by the wayside in 1995.
You can clear them, and reset the PCM to default:
Disconnect BOTH batt+ cables and ground one (discharges static and residual power). Wait at least 30 minutes (longer, such as overnight, is OK). UNGROUND BOTH batt+ cables and reconnect them. Wait about 2 minutes before KO or starting. If it doesn't work, repeat with a longer ground period. Most of them reset in 15-20 minutes, but some take a little longer. I don't know of one that's taken longer than 30 minutes, but I haven't done them all. Overnight never failed, though. That's also a good time to service, de-sulfate and trickle up the batteries, while disconnected (unless they're relatively new, of course).
Well today I had to go help my brother move so I filled the tank. And Pooof! SES is gone. Don't know if it was filing her up or key cycles that did it but SES is gone.
Now it will bug the shi!! out of me not knowing what caused it. You know Murphy, he will pop his head up at the most inopportune time. . . . . .
"The Constitution is not an instrument for the government to restrain the people, it is an instrument for the people to restrain the government."
-Patrick Henry
A5150nut
2006 K3500 D/A
94 6.5 4x4 5spd Sold
Sometimes, things just happen with no explanation. I have one recurring code that comes and goes, but it's somewhat predictable. I don't recall the DTC, but it's for a fuel temp error, accompanied with an unlisted (for the model year) "U" code, and it only happens during fall and spring, when the overnight temp and startup temp is specific. The fuel code sets the SES, but the "U" code alone doesn't. It's relatively harmless, and I'll do nothing about it. The only issue it causes is, sometimes it will cause the gear ratio program adjustment (for larger tires) to revert. It goes unnoticed until I get up to speed and the TC locks, when the tach doesn't match the speedo where it should. It takes about a minute to reprogram that, so no biggie. The codes disappear at the next startup once up to operating temp, and don't remain in history.
If the SES goes away and causes nothing negative, I'd just move on and not look back. If it returns, maybe have another look. Or not.