Here's a weird one...

[DJ BigDog]

So today while driving on an ugly PA road I hit a bone jarring pothole and the ** shut down for a split second, door's unlocked, CEL flashed on, it didn't seem to lose power completely but seemed like it reverted to just ignition on for a split second then everything returned to normal. It did this 2 more times on the drive, once at highway speed on interstate and once at about 45 on local road. All after big pothole hits. I already got under the dash and hood and check for loose connections at harnesses and lightly banged on the PCM to see if she'd shut off but couldn't duplicate issue. Any ideas from the brain trust on here? There's knowledge in numbers. Let's figure this out!

 

[ISU-152]

I'd pull the codes first. But maybe related to impact sensors if the truck shut down and unlocked the doors

 

[Rocket Man]

Ignition switch? Try jiggling it.

 

[iamdub]

Ignition switch? Try jiggling it.

My thoughts as well. I'm betting the OP has his locks programmed to unlock when the key is turned off.

Dan, grab your keys and/or fob as they hang out of the switch with the engine running and give 'em a few sharp tugs downward to see if it happens again. Speaking of, do you have a lot hanging (keys, fancy keyrings, etc.) out of the ignition switch? The weight of such items swinging and bouncing can take a toll on the lock cylinder/key switch.

 

[rockola1971]

Battery wires at the battery, starter and chassis ground connection. Check'em.

 

[RED TAHOE LS]

Battery wires at the battery, starter and chassis ground connection. Check'em.

Times two, GM battery cables are the worst, JMHO.
David g.

 

[iamdub]

Times two, GM battery cables are the worst, JMHO.
David g.

I agree that these are common problems and should be checked. But the locks unlocking when it happened is what leads me to suspect an intermittent connection in the ignition switch.

 

[rockola1971]

You mean the same symptom when a battery cable is loose (AKA Intermittent connection) spiking the BCM which can cause the locks to go Crazzeee.

 

[Rocket Man]

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[ISU-152]

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I feel the same