07 Nbs Tpms - Help!

[Zembonez]

Help!

 

My 07 NBS Sierra is giving me random "check left front tire pressure" and "check right rear tire pressure" messages. Once I drive a few miles it goes away and might not reoccur for several hundred miles (or several days). Tires are all inflated and check out fine. I do have aftermarket wheels but the OEM sensors are installed and there was no issue at all for the first 1000 or so miles.

 

My question is this:

 

Does the TPMS have a specific air pressure setting built in (or programmed in) or does it just sense a pressure drop to send a trouble message? I am running 32psi in my 275-55-20 Pirellis and they are firm and ride nicely. If the pressure is a programmed in deal, can I have it reprogrammed? I don't intend to increase pressures. The tires ride and handle great and I could care less about wear or fuel economy.

 

Any help?

[bobcat5544]

Document ID# 1875657

2007 Chevrolet Silverado - 4WD

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Subject: Low Tire Light On And Or DIC Check Tire Pressure Message When Cold - keywords air mil monitor program tpm wheel #PIT3569B - (12/04/2006)

 

Models: 2004-2007 Cadillac Escalade, Escalade ESV, Escalade EXT

2004-2007 Chevrolet Avalanche, Suburban, Tahoe

2007 Chevrolet Silverado

2007 GMC Sierra

2004-2007 GMC Yukon, Yukon Denali, Yukon XL, Yukon Denali XL

With RPO UJ6

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This PI is being updated to add models. Please discard PIT3569A.

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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

 

Condition/Concern:

The TPM system is required by law to warn the driver if the tire pressure is below 25% of the tire pressure displayed on the tire placard. It is possible to have one or more cold tires at the trigger point and when warmed up during operation exceed the trigger point. As a rule of thumb, tire pressure will increase 1 psi (6.8 kpa) for every 10 degrees F (5.5 degrees C).

 

Example: A 2005 Yukon has a tire placard value of 30 psi (206.8 kpa) cold. The customer drives the truck for several miles to get to the service station and the tire temperature is 65 degrees F (18.3 degrees C) when the tire pressure is adjusted. Unknowingly, a pencil style pressure gage that reads 3 psi (20.6 kpa) higher than actual pressure is used.

 

The vehicle sits outside at night and the ambient temp drops to 20 degrees F (-6.6 degrees C). The actual tire pressure in the morning is 22.5 psi (155.1 kpa), which is right at the borderline where the system is required to warn the driver of low tire pressure.

 

The customer drives away in the morning and notices a "Low Tire Pressure" message and a Low Tire indicator lit. The light goes out after several miles of driving and the customer does not see the message again until the next morning. The customer thinks there is a problem with the TPM system because they just had the tire pressures checked.

 

Recommendation/Instructions:

Two things are vitally important in the above example.

 

• Not all tire pressure gages are accurate

• Tire temperature significantly effects tire pressure.

 

The tire pressure should be set to the specified pressure at the lowest temperature the vehicle will be operated. Remember tire pressure goes up 1 psi (6.8 kpa) for every 10 degrees F (5.5 degrees C). If you are unsure of tire temperature when you are adjusting pressure, use an infrared temperature tool. If you have a tire temperature of 60 degrees F (15.5 degrees C) and you expect the ambient temperature to reach 20 degrees F (-6.6 degrees C) at night, add 4 psi (27.5 kpa) to the 30 psi (206.8 kpa) and set the tire to 34 psi (234.4 kpa) at 60 degrees F (15.5 degrees C).

 

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

 

OR

 

Document ID# 2000470

2007 Chevrolet Silverado - 4WD

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Subject: Service Tire Pressure Monitoring With Aftermarket Wheels - keywords C0750 C0755 C0760 C0765 DIC DTC inoperative sensor operation light tpm #PIT4422B - (07/27/2007)

 

Models: 2007-2008 Cadillac Escalade, ESV, EXT with (RPO UJ6)

2007-2008 Chevrolet Avalanche, Silverado, Suburban, Tahoe with (RPO UJ6)

2008 Chevrolet Express

2007-2008 GMC Sierra, Yukon, Yukon Denali, Yukon XL, Yukon Denali XL with (RPO UJ6)

2008 GMC Savana

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This PI Supercedes To Update Models. Please Discard PIT4422A

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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

 

Condition/Concern:

Some customer's may bring in their vehicle with a "Service Tire Monitor" message on the Drivers Information Center. Aftermarket wheels installed without the sensors will activate the "Service Tire Monitor" warning and will stay on until the sensors are installed. Even if the sensors are installed in aftermarket wheels they may not mount in the correct OEM orientation and still turn on the "Service Tire Monitor" message.

 

Recommendation/Instructions:

Before starting regular diagnosis, verify that the vehicle is equipped with GM factory or GM accessory wheels and tires. The wheels and tires should be the correct year and size that the vehicle was built with. If the vehicle is modified with aftermarket wheels and tires, do not perform any additional work until the factory wheels and tires are installed and the same concern can be duplicated for what the customer brought the vehicle in for.

 

Please make sure the customer's vehicle is equipped with the Factory wheels or GM accessory wheels before contacting the Technical Assistance Center

 

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

[Zembonez]

Document ID# 1875657

2007 Chevrolet Silverado - 4WD

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Please make sure the customer's vehicle is equipped with the Factory wheels or GM accessory wheels before contacting the Technical Assistance Center

 

Thanks. That's good info. It is full of the typical dealership "not our fault" text that one would expect in today's world, but it gives me a few avenues to investigate. It's too bad that we live in such a lawsuit oriented society that our government has to mandate such bull$hit on every vehicle. All it really does is make our drivers even lazier... if that's possible! HA!

 

I am not griping at you here. I really do thank you for the information. It's good reading that tells me a lot about the system that I was unaware of.

[Zembonez]

UPDATE...

 

A few pounds of air solved the problem. Next I'm going to dive into the computer's software and create a work-around in the system. Shouldn't be a big deal, it's all programming.

[Wingnut]

My buddy was having the same problem. I put an extra 4 or 5 lbs in each tire for him when I did his drop and it hasn't come back.

[99silveradoz71]

I would assume that you can over-inflate the tires and you won't get a message then? This thing only works with low pressure? I'm asking because I went up to an LT tire on my 99 which obviously has a higher pressure rating, and if I do so on the 08(when she gets here) down the road, I want to be sure I won't have the light coming on.

[Zembonez]

I would assume that you can over-inflate the tires and you won't get a message then? This thing only works with low pressure? I'm asking because I went up to an LT tire on my 99 which obviously has a higher pressure rating, and if I do so on the 08(when she gets here) down the road, I want to be sure I won't have the light coming on.

 

As I understand the system, it uses a base number that is programmed into the system like 35psi. When you lose 25% of the air in that tire it is supposed to trigger a warning. I don't think it would be capable of detecting an overinflated tire at say 45psi, but you would have to lose a lot of air to trigger a low tire. I'm sure it is programmable but I haven't jumped into that yet.

 

If you use the OEM sensors, don't buy GMs hogwash about aftermarket wheels. The sensor isn't smart enough to know what kind of wheel it is in... YET. (but I bet the GM engineers are trying to figure that out) The trucks already "know" where you are through onstar whether it is activated or not.

[Zembonez]

My buddy was having the same problem. I put an extra 4 or 5 lbs in each tire for him when I did his drop and it hasn't come back.

 

Yup, mine was just low enough to trigger the system when cold and would go off as the tires warmed up and gained a couple of pounds of pressure. Wacky huh?

[Blacklabel Denali]

While visiting Arizona my tire warnings were going off regularly though it didn't say whether it was low or high but the pressures were at about 40 psi. coming back to San Diego stopped the warnings.

[abager2]

i have had a similar problem with the tire light...i put on aftermarket wheels as soon as i bought the truck...had absolutely no problem with them until i rotated the tires yesterday.the dash says i need to relearn the tire positions,so i dug out my owners manual and without the dic in my truck,the manual says to 1) set emergency brake 2) turn key to run position 3)press odometer stem until tire program message shows 4) press once till tire relearn active shows and horn honks twice 5)starting with lf tire,either add or bleed air until horn honks once(this could take up to 30 seconds and you only have 2minutes total for first tire) 6)after horn honks,switch to rf tire,then rr tire and finally the lr tire...you only have a total of five minutes to get them all or you have to restart the whole process at the lf tire...the problem i have had is that it takes about 2 minutes to get the horn to sound on the lf tire and then the rf never sounds the horn..so i have to start over again...it does not seem as though the sensors are sensing the pressure changes...i have tried deflating and adding air,but to no avail...am i missing a step???

[abager2]

well, after trying all the different methods listed here in the forums for resetting my tpms sensor locations and the outlined instructions in the manual.i finally figured out what would work...i must have went thru the tire re-learn process 15 times before i finally deflated all four tire to 20lbs and then went thru the process and it actually worked..when finished the display said that all four tires were low and after airing them up to 34lbs each the light went off and it is now fine...i cant believe the grief a simple tire rotation caused me,but i now know how to do it...i just ordered the driver info panel from gm accessories website and will be installing it when it arrives,so i will have to learn the procedure for that. i do not know why the sensors would not re-learn with normal pressures,but it worked like a charm with low pressures...

[critter]

Rotated my tires this weekend and could never get the tires to relearn. On about the 4th try the whole system cratered and have the "dreaded" Service Tire Monitoring System warning on my DIC.