When you scan the codes, what do the fuel trims show? (they should be labeled LTFT and STFT or something containing those combination of letters)

I would not replace the O2 sensors without first knowing these readings. They generally range from -25% to +25% (should be much closer to 0% for a properly operating setup and higher for issues like a vacuum leak or leaking injectors). If your fuel trims total to a high positive percentage (indicating lean condition), then this would point to a narrower range of issues. Fuel trim information is stored with the codes as a freeze frame. Often times there is a different cause for O2 sensor codes than the sensors themselves. Ofcourse there is the possibility of them being bad, indeed. Fuel trims will give a much larger clue (and much cheaper, potentially). I would pop the connector off and inspect the terminals, as well. If you have a multi-meter, you can test the O2 circuit to rule that out, too.

 

You might have "heard" that. but ...................... uugh, NOT TRUE. The H3 TPMS are not nearly that smart and have no idea what environment they are in. They sense air pressure and transmit that when the tires are rotating...... period. The BCM does the rest, like compare the pressure sent by all 4 TPMS in rotating tires in comparison with each other.

 

(US) GM-3 BATTERY TPMS sensor bypass simulator Hummer GMC Chevrolet Cadillac etc

 

From an old post: https://www.hummerforums.com/forum/h...ms-hell-40214/ . The TPMS settings are adjusted in the BCM using a diagnostic scan tool, like an Autel, not in the TPMS sensors themselves (TPMS: tire pressure monitoring system). I stand by my previous statement and believe the settings for the TPMS can influence this issue. Do you have evidence against this? I have personally used an Autel to access these settings on my H3, and I could indeed change the ply rating of the tire, which has been previously found to cause TPMS faults (as outlined in the quotes below from a previous thread).

My suggestion is aimed towards helping resolve the issue by verifying the settings in the TPMS using a scan tool. If the settings are "factory," this issue would be ruled out. If the settings have been changed, resetting them to "factory" may either resolve the issue or otherwise rule the issue out.

 

Like I said, the BCM does the rest. The sensors themselves are stupid and have no idea what environment they are in. Tire Pressure Monitoring Sensors = TPMS.

You interchanged terms, not me. The adjustment you speak of is to how the BCM is set to expect the signal, (which channel) has zero to do with the sensors themselves.

This stuff is not complicated.

 

All H3's are either 30psi or 35psi. Warning light comes on when signal is 20% below spec.

 

https://www.firestonecompleteautocar...oes-tpms-mean/

^Tire Pressure Monitoring System (TPMS) ...and with this, I exit the pee'ing match. I'm offering a genuine and informed suggestion. Thanks for the critiques, "doc olds."

 

The BCM is only looking for a the proper voltage signal. Did you watch the video I posted above, no tpms sensors installed, used a simulator only.
Here's how to program the simulator GM. Note: air & rotating tires not necessary:

 

Why do you keep posting bs firestone links? "It measures the tire’s pressure and notifies the driver when pressure drops 25 percent or more below the manufacturer’s recommended level"
BS!!!! My Recommended tire pressure is 35psi, the lowest pressure I can drive until the warning light is 29psi (17% drop).
25% drop: 35 x .75 =26.25psi

 

Haha I was just referencing the TPMS acronym, nothing else in the firestone links. I did see your videos and they are very informative. The bypass module seems like it would work well!