08 GM Tire Pressure Sensor Question

[IndyFan]

I've got an 08 Chevy Express 3500 van. It has tire pressure monitors in each wheel. I just put new tires on the van today, and the monitors are now not on the correct wheels. I've got the recommended 50psi pressure in the front tires, and 80 in the rears. I verified this with an accurate gauge. The problem is that one of the wheels was previously on the rear and has been moved to the front, and vice versa. So I'm getting a warning that one tire on each end is low. It is showing the correct pressure for each tire, but because the sensor is in the wrong position, I'm getting the warning.

How do you set the tire pressure monitors for the right position? I assume this can be done, otherwise, how the heck can you rotate tires without changing the position of the sensors?

Any help with this would be appreciated. ( hope I explained this well enough to be understood correctly.)

 

[IndyFan]

Got it! I found the process in an online owners manual. It is kind of a pain in the butt, but at least I know how to do it now.

Just in case anyone searches for this topic, I'll post the link to the owners manual.

http://www.chevrolet.com/assets/pdf/owners/manuals/2008/2008_chevrolet_express_owners.pdf

I've got to go through a process of deflating each tire while it is in detection mode. Then, it will recalibrate the sensor to its new position. It is a pain, but I like this system, knowing my wife and kids are riding around in this vehicle. It has alerted her before when a tire was going down. Great feature!

 

[kasedian]

Yep. I have an 08 Chevy PU, and did the same thing. It is a PITA.

 

[George Bynum]

I bet that next time you mark the wheels when you buy tires ...

 

[IndyFan]

Originally Posted By: George Bynum
I bet that next time you mark the wheels when you buy tires ...


Yeah, but it is good to learn how to do this anyway. I'd have to figure it out when I rotate them in 6000 miles.

I'm a little surprised Discount Tire didn't mark them. I would imagine they'd have customers driving them nuts with their tire pressure warning lights going on after new tires.

 

[bdcardinal]

When digging through some tool porn, i mean my Matco catalog they make deflators for cars with TPMS that screw onto the valve stem and are marked with the location the tire goes back to.

 

[Vikas]

Given that any car which has TPMS, also has four wheel ABS; why in the world does it need TPMS? If the tire pressure is much different on two sides, the difference in ABS wheel sensors is enough for the computer to figure it out.

How did we get TPMS shoved down our throat?

- Vikas

 

[leeharvey418]

Originally Posted By: Vikas
Given that any car which has TPMS, also has four wheel ABS...


Not so. Indirect TPM systems rely on ABS sensors to (very roughly) gauge tire pressure. Vehicles with direct TPMS do not necessarily have to have ABS.

...of course as of MY2012, all new vehicles sold in the U.S. will be required to have stability control (a worthwhile safety enhancement in my opinion) and therefore will have both ABS and TPMS.

 

[sciphi]

Originally Posted By: Vikas
Given that any car which has TPMS, also has four wheel ABS; why in the world does it need TPMS? If the tire pressure is much different on two sides, the difference in ABS wheel sensors is enough for the computer to figure it out.

How did we get TPMS shoved down our throat?

- Vikas


The Ford Exploder rollovers caused by failing Firestones in the mid-1990's due to an absurdly low recommended pressure, people not checking the tire pressure, and running 10 PSI tires at 75-80 mph during summer with a loaded down vehicle. IE, the worst case for tire failure happened to a lot of folks.

 

[Vikas]

Do they sell cars in this country without ABS anymore?

What are the thresholds of "real" TPMS before the indicator turns on? I would think ABS system would be able to discern under those conditions.

It seems as if TPMS and specific implementation (i.e. direct reading of tire pressure instead of indirect through wheel speed sensors) was mandated. If that is the case, it is very unfortunate.

- Vikas

 

[leeharvey418]

Originally Posted By: Vikas
Do they sell cars in this country without ABS anymore?

Not as of MY2012 when all new vehicles are required to have stability control systems - if a vehicle has stability control, it necessarily has 4-channel ABS.

Originally Posted By: Vikas
What are the thresholds of "real" TPMS before the indicator turns on? I would think ABS system would be able to discern under those conditions.

I believe the standard says that the MIL has to illuminate at 75% of placard pressure, so 24 psi for a 32 psi placard pressure. The biggest problem with indirect TPMS is that if all four tires lose pressure at the same rate, there's no difference in rotation speed for the ABS controller to notice.

Originally Posted By: Vikas
It seems as if TPMS and specific implementation (i.e. direct reading of tire pressure instead of indirect through wheel speed sensors) was mandated. If that is the case, it is very unfortunate.

I believe there was a period when either indirect or direct systems were acceptable, but I'm almost 100% sure that to comply with the current FMVSS new vehicle must use direct pressure monitoring. ...and yes, it is unfortunate, especially when manufacturers make it impossible to do things like swap out a set of winter tires without going to the dealer to reprogram the system.

 

[SteveSRT8]

Easy guys, not all the systems are so goofy.

I was just at Tire Kingdom and the tech got out his scan tool and was getting in the car and I asked him why. "To recalibrate your tpms" was his reply.

When I told him my car doesn't require this procedure he was dumbfounded.

On my car it simply figures it out. Might take it up to a hundred feet or so, but you can move the wheels any way you want without issues. I'm sure other cars must do this as well.