P0102 MAF Signal and Voltage, Signal 9V ?!
 

I have one CEL on my 2002 C5Z and I'm having a hard time. P0102 for MAF Signal.

I tested the Voltage and checked ground resistance. The MAF Signal voltage is off, reading high. Here are the results

Pink: 12v
Yellow: 9v-10v
Black: 0v, with .01 Ohms to ground

Purple: 2v
Orange: .02v

The yellow signal wire is supposed to see 5v and is consistently reading 9v. This is of course the issue, but I can't see any issues in the harness. The car does have a mail order tune/pcm but it's from the previous owner and I have no idea what's on it.

When I clear the code while running, the car dies. It cranks once and shuts off, then runs on next start. It will drive one cycle without CEL, then next startup throws CEL for P0102. While CEL is off it shows a Current P0102 but doesnt go Hard until next start. Car runs fine afterwards, I'm just trying to get it registered and inspected and need to resolve the CEL.

What would cause HIGH MAF Signal Voltage? Wrong MAF? Bad MAF? Short to 12v signal (doubtful since other sensors read fine, also tested with no continuity between)? Speed density tune?

Can someone point me in the right direction?

So far I'm thinking new China MAF for $30, it's worth a shot. (I'll return it if it doesn't fix).

Sounds like you and I suspect the same thing. On the other thread you posted on, I posted asking if maybe both you guys' MAF's were bad or very dirty. I guess we will soon see! lol

New MAF FIXED, no CEL after a couple drive cycles. MAF was $25 BNIB on eBay...

Update:
No code with new MAF but the engine stumbles around 5000rpm and wont rev past under WOT. Unplugged the MAF and revs out all the way. I'm guessing its the china maf being from china...
guess I'll replace with OEM and post an update.

Update:
New OEM ACDelco MAF (LS6 PN) was pricey at $150 but it's solved now.