RE: new tires = low tire pressure warning?
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RE: new tires = low tire pressure warning? - 7/25/2007 11:12:20 AM
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Dennis
Posts: 7584
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Okay here is the whole ball of wax...Iwas sorta wrong about them being compared..but not completely..
Tire Pressure Monitoring System Information
Components
There is a separate sensor/transmitter in each wheel. The TPM system shares the receiver with the keyless entry system. Data from the receiver is displayed on the instrument panel, using the driver information center (DIC).
Sensors
The sensor, with built-in valve stem, is inserted from the inside of the wheel, through a hole in the rim. It is retained by a nut (4 N.m, 35 lb. in.) and is sealed by a grommet. A lithium battery with a design life of 10 years powers the sensor.Each sensor is coded differently. This permits the receiver to determine exactly which tire is over or under-inflated.
Operation
The sensors operate only above 20 mph (32 kph) and transmit once per hour when parked, to preserve battery power.
If the pressure in a tire rises or falls outside the calibration limits, the condition is displayed by the DIC. The low limit is 24 psi (168 kPa) and the upper limit is 39 psi (272 kPa).
Service
The sensors are lightweight, only about an ounce (28 g), and this small weight is easily accounted for during normal tire balancing.
The sensors are mounted within the well of the rim. It’s important to be careful when using a tire-mounting machine. The sensor could be damaged in two ways: either by (1) direct contact with the machinery or (2) by the bead of the tire as it is forced over the rim. Use care when using tire machine. Consult tire changer manufacturer’s support material for proper mounting procedures.  Sensor ruined by tire mounting equipment The valve stem cap is made of aluminum and the valve core is nickel-plated to resist corrosion. The end of the stem serves as the sensor’s antenna.TIP: Do not replace either the cap or the valve with standard parts. This will interfere with the sensor’s ability to transmit.
TIP: The TPM sensor is more precise than consumer-grade tire pressure gauges. It may be necessary to explain this if the customer routinely mis-inflates tires using a gas station gauge.
Receiver Programming
The receiver is programmed at the factory to recognize which sensor is at each wheel location. If tires are rotated or a sensor is replaced, the receiver must be reprogrammed, following SI procedures.
If the receiver is not reprogrammed, the system will continue to report the correct pressures, but will assign them to the wrong locations on the vehicle.
TIP: There are two reprogramming methods. You must use the J-41760 magnet when a new sensor is installed. During tire rotation, you can use either the magnet or your Tech 2.  J-41760 Magnet Magnet Method
You will have only one minute between horn chirps, and five minutes overall, to complete the procedure once you start.
With ignition on, engine not running, press both lock and unlock buttons on the key fob. A horn chirp within 10 seconds indicates that the receiver is in programming mode.
At each wheel, hold the J-41760 magnet over the valve stem until the horn chirps, to force the sensor to transmit its code. You must follow this order: LF, RF, RR and LR. The horn chirps twice to indicate completion.
Scroll through the DIC readout to verify all four pressures are displayed.
Tech 2 Method
With the TPM Reprogramming procedure on your Tech 2, you can command each sensor to its new l
< Message edited by Dennis -- 7/25/2007 11:13:51 AM >
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RE: new tires = low tire pressure warning? - 7/25/2007 11:34:25 AM
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mfish
Posts: 382
Joined: 4/9/2007
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I dont get why we have to reprogram at each tire rotation. The system doesnt tell us which tire is under/over inflated, it just tells us one of the tires is improperly inflated, so why does the receiver need to know where each sensor is, all the tires have the same recomended pressure.
I have had several rotations so I guess Hummer is doing the reprogramming for me.
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06 H3; adventure & lux package; Gibson catback; readylift leveling kit; and some other stuff...
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RE: new tires = low tire pressure warning? - 7/25/2007 12:46:15 PM
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D VADER
Posts: 1191
Joined: 5/21/2007
Status: offline
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O.K. I'M GONNA BELLY UP TO THE BAR AND MAKE MYSELF LOOK STUPIDER!
It use to be air pressure sensors were associated with run flat tires but I see they are being offered on other cars set ups. Anyway I looked at the Hummer websight and my manual to see if this was standard. Then I checked the Adventure Package but I see no mention of this. Please bring me up to speed. I kinda hope I don't have them.
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2007 H3X w/lux pkg, black on black, Starship from the "Dark Side"
Central Ohio
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RE: new tires = low tire pressure warning? - 7/25/2007 12:48:49 PM
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mfish
Posts: 382
Joined: 4/9/2007
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hhhmmm...I noticed this in Dennis' post:
"If the receiver is not reprogrammed, the system will continue to report the correct pressures, but will assign them to the wrong locations on the vehicle."
It sounds like our TPM system is the same used on many GM vehicles. Some of those vehicles have the capability of telling you which tire is low, so reprogramming the sensor locations would be important. The H3 does not use this feature so it sounds like reprogramming is pointless. 
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06 H3; adventure & lux package; Gibson catback; readylift leveling kit; and some other stuff...
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RE: new tires = low tire pressure warning? - 7/25/2007 12:50:54 PM
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mfish
Posts: 382
Joined: 4/9/2007
Status: offline
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As far as I know they are standard. Why wouldn't you want them?
quote:
ORIGINAL: D VADER
O.K. I'M GONNA BELLY UP TO THE BAR AND MAKE MYSELF LOOK STUPIDER!
It use to be air pressure sensors were associated with run flat tires but I see they are being offered on other cars set ups. Anyway I looked at the Hummer websight and my manual to see if this was standard. Then I checked the Adventure Package but I see no mention of this. Please bring me up to speed. I kinda hope I don't have them.
_____________________________
06 H3; adventure & lux package; Gibson catback; readylift leveling kit; and some other stuff...
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RE: new tires = low tire pressure warning? - 7/25/2007 12:56:59 PM
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D VADER
Posts: 1191
Joined: 5/21/2007
Status: offline
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quote:
ORIGINAL: mfish
As far as I know they are standard. Why wouldn't you want them?
quote:
ORIGINAL: D VADER
O.K. I'M GONNA BELLY UP TO THE BAR AND MAKE MYSELF LOOK STUPIDER!
It use to be air pressure sensors were associated with run flat tires but I see they are being offered on other cars set ups. Anyway I looked at the Hummer websight and my manual to see if this was standard. Then I checked the Adventure Package but I see no mention of this. Please bring me up to speed. I kinda hope I don't have them.
I don't feel a need for them. I see they make tire rotation more difficult for a DIY and it's something else that can go wrong. I have a digital guage in my console and can monitor my own.
Are we sure they are standard?
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2007 H3X w/lux pkg, black on black, Starship from the "Dark Side"
Central Ohio
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RE: new tires = low tire pressure warning? - 7/25/2007 1:43:29 PM
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f5fstop
Posts: 51
Joined: 7/13/2005
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That information posted by "Dennis" is not the correct information for the Hummer H3 or for most GM vehicles with the new tire pressure monitoring system. These are the old 'magnetic' switched sensors used on older model Cadillacs, and Corvettes.
Basically the system on the H3 operates:
The BCM can only decipher signals from four sensors, even though 06 and 07 vehicles have five sensors. That is why the four sensors on the ground have to be programmed into the BCM; the spare is then ignored. The BCM will only signal that a tire is low on pressure, it will not tell which tire; therefore, the sensors are NOT programmed to a specific corner of the vehicle. For that reason, on this system, you can rotate the four tires on the ground and not have to reprogram the system for those sensors. If you add the spare into the rotation, you will have to program the four sensors on the ground to remove the one sensor that is now the spare. Corvettes and Cadillacs do read the corner specific sensors, and will tell you which tire is low, the H3 will not.
You cannot program these sensors using a magnet or the Tech 2. These are NOT magnetically controlled valves as used in older Corvettes, these are different. The dealer has a tool (J-46079) that excites the sensor to send out a signal. When doing a relearn or program of the four sensors, you set the BCM into learn mode, and then, if doing the program with a tool, you walk up to a tire, hit the button on the tool, the horn honks, and you move onto the next designated tire until all four on the ground are programmed into the BCM. If doing it at home, enter the learn mode and let air out of a tire or add air until the horn honks and move on to the next tire. During learn, the BCM learns the serial number of the correct sensors. Since the BCM can only read four sensors, the spare sensor is ignored.
The serial numbers of the sensors are NOT lost if the battery is disconnected. If so, I would have had to relearn my sensors every time I wired in another electrical device. Then again, I KNOW how this system works, and again, it is not as described in the earlier thread.
I guess I should say I'm sorry for disagreeing with the administrator, but can I read this thread knowing information is incorrect?
I might add that the tire pressure monitoring systems are required by Federal Law, and were phased in over a two year period. I believe all vehicles built after this September are required to have a direct read method, which is what the H3 has.
The averaged system was vetoed by the Feds. In the averaged system, the computer looked at the speeds of four ABS wheel speed sensors, and if one was at a different speed it was assumed this tire was low. Accuracy was terrible, and if all four tires were low, the computer could not determine if they were dangerously low. Therefore, if all four tires were at 5 psi and ready to blow, all the computer would know is that all four wheels were turning at the same speed.
< Message edited by f5fstop -- 7/25/2007 1:50:19 PM >
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RE: new tires = low tire pressure warning? - 7/25/2007 2:30:53 PM
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jpac4lyf
Posts: 51
Joined: 7/24/2007
Status: offline
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this is great info... I'm planning on faxing your advice to the dealer as we speak to help my truck if not others too.
So, in the grand scheme of things when I get my H3 back from the dealer tomorrow due to the Tire Pressure alert, how concerned should I be if on Friday the damn TPMS light comes on again?? Do you feel as long as I gauge the pressure on my own all is well... or do you feel like the dealer should keep it til they get the thing right? The 07 H3 is only 4 weeks old after all? They are working on my pressure issue right now in Scottsdale!
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RE: new tires = low tire pressure warning? - 7/25/2007 4:52:20 PM
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f5fstop
Posts: 51
Joined: 7/13/2005
Status: offline
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quote:
ORIGINAL: jpac4lyf
this is great info... I'm planning on faxing your advice to the dealer as we speak to help my truck if not others too.
So, in the grand scheme of things when I get my H3 back from the dealer tomorrow due to the Tire Pressure alert, how concerned should I be if on Friday the damn TPMS light comes on again?? Do you feel as long as I gauge the pressure on my own all is well... or do you feel like the dealer should keep it til they get the thing right? The 07 H3 is only 4 weeks old after all? They are working on my pressure issue right now in Scottsdale!
We had some early on problems with early 06 H3s, but primarily most of the problems were due to incorrect tire pressure and fluctuating temps. Example, if your recommended TP is 35 cold, and in July it was set to 35 on a cold tire. Then along comes the fall in November, warm days, cold nights. Your tire will lose 1 psi for ever 10 degree drop in temp; therefore, if the tire was set on a 90 degree day, and it is now 40 and at night it dropped to 30, you are now 6 psi under. Therefore, if you start the vehicle at 30 degrees, the TP low signal comes on, and you drive a few miles and the warning goes off, it means the tires have warmed, pressure increased and pressure now exceeds the set point to set off a sensor.
That is how it works in a perfect world. If the dealer spends some time, the system can be diagnosed. Depends on how much time the dealer wants to spend. Primarily there are two unique messages that may be outputted. One is something like "check tire pressures" which implies a sensors sees a low tire. The other is something like service the tire pressure system or tire monitor, and means there is a fault in the system.
Usually the check tire pressures means there is a low tire, that may have increased in pressure on the drive to the dealership in the day. The other warning message indicates there is a problem with the system, and this could be a sensor, BCM calibration or a BCM.
A few points to always remember about this TP system, or any other system used by any other manufacturer.
1. Always check tire pressures on cold tires. Cold not meaning ambient temps, but a tire that has not been driven in over three hours.
2. Make sure there is NO sunlight shining on a tire or tires. Direct sunlight can raise TP by up to 2 psi.
3. Check pressures every month or sooner if there is a drastic weather change (global warming or an instant ice age)
4. If rotating the four tires on the ground, no need to reprogram these sensors. (If you have a corner specific system like on a Cadillac or Vette, etc., you do need to learn for each corner. However, the system will not know you rotated the tires, it would just output the wrong information for which tire is low. Or in the case of some, you can push a button and see the TP for any of the four tires.)
5. If rotating with a spare, you must put the BCM into program mode and program the four on the ground. If not, the spare that is now on the ground will not be read by the BCM, and the BCM will continue to read the new spare.
6. If you get a sudden cold wave, and you get a low tire pressure warning in the morning that goes away after driving, it is low pressure due to a change in temps. Time to recheck the pressures.
7. If off-roading and you lower your TP, you will have to ignore the message and warnings. I made a suggestion, at the request of someone online, about turning off the system if the t/case is put into 4-wheel low lock. GM will not do this due to the liability. This is a Federal requirement, thanks to Ford/Bridgestone-Firestone, and primarily thanks to those people who ran tires too low, with overloaded Explorers, in extreme warm conditions that caused a tire to explode, rolling the Explorer and killing someone.
As for your specific problem, I'm not there so I can't say. If it were ME, and I knew the pressures w
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