TPM Probs, NOT sensors.
 

I have an intermittent CHECK TPM notification on my 2007 H3 with 78k miles. I've replaced all 5 sensors with no improvement. It might go 2 days and then it comes on and sometimes goes out while I'm driving. I've tried to find info on exactly how this system works but have failed. I have found that the chincier systems use the antenna for the keyless remote and some have an antenna at each wheel. Since I can't find anything at each wheel I'm assuming the H3 uses the keyless. Anyone here know how this system works?

If you could get the code from the system it will give you somewhere to go. There should be a code or codes somewhere stored in the tpms module. I assume the system uses the tpms module to get the information wirelessly from the sensors and uses it's own antenna built into the module.

I have found out that "Low tire" and "Check TPM" relate to obvious different problems but I cannot find any code regarding TPM when I check them. I do have a code for secondary air pump that has been a problem since I bought it 3 years ago and a non descriptive missfire code that has only been showing up intermittantly the last month. I'm going to see if the missfire is due to water collecting on the #1 plug as discussed elsewhere here. The air pump is because the fan motor is siezed as also I hear is common.

You can try re-programming the TPMS (instructions are in your manual). Each tire has a transmitter built into the valve stem (inside the tire) that communicates with the system. From what I have been told, the system is very sensitive, and ALL 4 tires must be within just a few psi of each other. Also, it seems that the PSI must be high (45 psi?). I know that when it's cold out, I sometimes get a low tire message until I drive about 20 minutes to warm the tires up.

You might be able to have a good tire shop able to tell you which tire/sensor is causing the issue; the batteries only last about 7-8 years, and maybe one of the new ones you bought had a bad battery in it?

The system only monitors 4 at a time. They only transmit when rotating, they turn off when no movement is detected after a couple minutes.

You never mentioned what PSI you have the tires set to. Back in the day, when these trucks were being sold, there was no shortage about complaints with the TPMS, 99% made by people who never physically checked the PSI in their tires. The standard response to the complaints was a simple, make sure the four tires on the ground all have exactly 38 PSI Cold, anything less or any variance cause problems.

Waht Doc said AND, if you have 5 TPMS then you will have to make sure the 4 on the ground are programmed to the truck. If the spare has a TPMS, it should not be programmed to the truck until it is on the ground.

It seems like everyone here has had about the same luck I have in finding out exactly HOW this system works. No wiring diagram. No specification regarding antenna placement.

Tire pressures have been checked both by me and by the tire store that put in the new sensors. They also verified that all sensors have proper signal. The fact that the problem is intermittent shows that there cannot be a completely failed component. Of course they also did not know specifics as to how this system works. I think they are keeping all this info very tight to the chest...

the bcm gets the signals,,,but how?.
i searched my paper svc manuals,3 of them,8 inches thick!,cant find where the pickup is.
if its the digital ant it could be unhooked to see /verify it.
it must be a single pickup ant or the learn mess would not be so ,,,messy!

The system is sensitive. The codes you are getting on your scanner are for the Engine Management Module or PCM. You need the codes from the TPMS module. Most generic code readers only get into the PCM which is for the engine. Depending on the vehicle it may allow you to see transmission codes. A few code readers will also access the Airbag and/or ABS system as well. There are about 13, or more, computer modules in your Hummer. A generic code reader can only get to one. Like I said in my previous post, you need to get the codes from the TPMS module to get an idea of what is wrong. There should be a bunch of low tire codes and a few sensor codes. You might have to clear the codes and drive it to see what codes come back. It could be as simple as unplugging the module and plugging it back in. Bad connection at the plug. It could also be more serious like a failing TPMS module.

tpms module??. where did you come up with that?
i see no mention of it anywhere i look. the bcm gets the signals, from ?? it looks like they come thru the digital radio.
i thought it was the digital radio ant. if it is,i killed my onstar yrs ago and i thought i unhooked the digital ant, but my tpms is working!
im still looking thru schematic wiring but its messy.

can anyone verify that the digital radio is onstar and satellite radio.?.
i dont use either but i get sat signal advertizing