I have a stock truck with 65,000 miles and this was the first time
the SES light came on.

Yesterday, we were traveling the Hwy 88 grade over the Sierra's and
the Service Engine Soon light came on. We lost some power climbing
the steep grade, however, all seems fine now.

I checked with a diagnostic tool and it showed code P0540
Code Intake Air Heater A Circuit. I cleared that code.

Searching the archives, it looked like I had an over boost problem.
Could I have done any damage or is throwing a code the way the
engine protects itself?

Thanks

I have a stock truck with 65,000 miles and this was the first time
the SES light came on.

Yesterday, we were traveling the Hwy 88 grade over the Sierra's and
the Service Engine Soon light came on. We lost some power climbing
the steep grade, however, all seems fine now.

I checked with a diagnostic tool and it showed code P0540
Code Intake Air Heater A Circuit. I cleared that code.

Searching the archives, it looked like I had an over boost problem.
Could I have done any damage or is throwing a code the way the
engine protects itself?

ThanksTruck sounds like it's doing it's job just fine. I would'nt worry about it.

I had the same thing/same code happen to me last year travling through eastern Utah. Other then a little anxiety over the SES coming on in the middle of nowhere (no offense to Utahians) it was not a problem. We continued our trip and when we got home dealer replaced the control relay for the intake heater under warranty. I would of thought that a SES set by intake heater failing would of come on when I first started the truck. Mine came on in the middle of the afternoon just driving down the hyw........

Check your 15 amp fuse under the hood in the electrical control box.

THat should be covered under the 80,000 mile emissions warranty IIRC

Dealer said I lost a glow plug which set off the P0540 code. $100 deductible applies
under the 5 year, 100,000 mile warrenty.

Does GM want the dealer to replace all 8 as with the fuel injectors?