I'll start by saying that I have had my C6 since 10/25/04, and I love it. I just turned 600 miles, but last night I experienced a small problem. The "Service Tire Monitor" message appeared on the DIC; and in the tire pressure screen, on the DIC, it registered my right front tire pressure as "XX". At that time, I pulled over thinking that my tire was possibly punctured or had lost significant pressure (and I wanted to confirm this before proceeding on the run-flat). I checked the tire pressure with a guage and found it to be normal (32.5 psi). So, I consulted the owner's manual, looked up the DIC message, and read that it was probably a problem with the tire sensor. I drove it to the dealership today and they confirmed that it was definitely a bad sensor, that they were not successful in being able to re-initialize. So, they are going to have to order a new sensor, and they weren't really sure on how long it would take to get a new sensor from the Corvette factory. I just thought I would post this, in case other owners experience this message appearing on the DIC display.

 

That is the problem with these newer cars just too much stuff, small stuff, whatever to go wrong. I rather take my own tire pressures the way I was raised but I understand now this has become law because most drivers are negligent in this area of maintenance.

 

yeah my traction control is messed up on my c6 it doesnt even work the deal is stupid too i brought my car in still doesnt work

 

The tire pressure monitor is invaluable for alerting the driver while driving that there is a problem with one of the tires. If it hits 25 lbs. while I'm on the road, I head for the nearest gas station.

It saved me once from being stuck in the middle of nowhere, and having to use my "old fashioned" pressure gauge to tell me what I already knew, that I had a flat tire.

Had the tire repaired, and was on my way in twenty minutes. BTW -- these were non-runflats, where the pressure warning system is even more important.

Cheerio!

 

Never heard of this law. State or Federal law? If state law, what state? How does it read (exactly what does it say)?

 

http://www.semashow.com/planner/semi...p?eventid=1195

http://www.consumeraffairs.com/news02/inflate.html

May 19, 2003

Motorola's Semiconductor Products Sector Tire Pressure Monitoring Sensor: MPXY8020A

Release Background

The TREAD Act and NHTSA Ruling
The Transportation Recall, Enhancement, Accountability and Documentation (TREAD) Act became law in the United States on Nov. 1, 2000.

This legislation gave rulemaking authority to the National Highway Traffic Safety Administration (NHTSA) and mandated that the agency carry out a number of critical tasks. This included the completion of "rulemaking for a regulation to require a warning system in new motor vehicles to indicate to the operator when a tire is significantly under-inflated."

With this mandate in place, NHTSA established a Federal Motor Vehicle Safety Standard for all passenger cars, trucks, multipurpose passenger vehicles and buses with a gross vehicle weight rating of 10,000 pounds or less, except those vehicles with dual wheels on an axle.

The agency issued the ruling in two parts, the first of which is detailed in this document. Under the ruling, manufacturers were given two options for compliance within a three-year window from Nov. 1, 2003 to Oct. 31, 2006:

- "Four-Tire, 25 Percent" Alternative
This involves alerting the driver when any single tire (or a combination of tires up to four) on the vehicle falls to 25 percent or more below the vehicle manufacturer's recommended cold inflation pressure for the vehicle's tires (known as the placard pressure), or a minimum level of pressure in the standard, whichever is higher.

- "One-Tire, 30 Percent" Alternative
The second option requires that the driver be warned when the pressure on any single tire falls to 30 percent or more below the placard pressure, or a minimum level of pressure specified in the standard, whichever is higher.

To facilitate compliance, the NHTSA developed a phased schedule as follows:
- Ten percent compliance during the first year (Nov. 1, 2003 to Oct. 31, 2004),
- Thirty-five percent during the second year (Nov. 1, 2004 to Oct. 31, 2005),
- Sixty-five percent during the third year (Nov. 1, 2005 to Oct. 31, 2006).

After the phase-in, NHTSA plans to determine if one option should be terminated, making the other option mandatory for all passenger cars.

Direct and Indirect Tire Pressure Monitoring
Direct tire pressure monitoring systems (TPMSs) have a sensor module at each wheel. These transmit pressure and temperature information to a receiver and are usually attached to the tire's inflation valve.

The sensor broadcasts data to a central receiver, or in some cases to individual antennae, that transmit data to the control module, which analyzes them and sends appropriate signals to a display. The four-tire, 25 percent requirement above employs the direct TPM approach.

Indirect TPMSs do not have tire pressure sensors and instead rely on the wheel speed sensors in an anti-lock brake system (ABS) to detect and compare differences in the rotational speed of a vehicle's wheels. This approach is the one currently in effect and meets the requirements of the one-tire, 30 percent alternative outlined above. According to its findings, NHTSA believes currently that direct tire pressure monitoring is the more desirable form of tire pressure monitoring and anticipates that it may satisfy the government's requirements best.

The MPXY8020A
Motorola's MPXY8020A TPM sensor chip offers drivers/consumers the following benefits:

- According to the NHTSA, annually in the U.S., an estimated 23,000 crashes and 535 fatal crashes involve blowouts or flat tires. While the NHTSA does not collect tire pressure data during crash investigations, it is assumed that low tire pressure is a factor in a large number of crashes involving blowouts, vehicle handling and hydroplaning.

- In addition to helping manufacturers comply, the MPXY8020A can help reduce blowouts, prolong tire life, shorten braking distance and improve gas mileage for vehicles and ultimately may help save lives for vehicle owners and their passengers.

For additional information about the MPY8020A, including product features, graphics, support and more, go to: http://e-www.motorola.com/collateral...tml?tid=TSPGPR.

NHTSA will publish the second part of the ruling by March 1, 2005, to provide sufficient compliance time for manufacturers.



http://www.nhtsa.dot.gov/cars/rules/...sts.html?name=

http://www.nhtsa.dot.gov/cars/rules/...eprmonsys.html

http://www.nhtsa.dot.gov/cars/rules/...l/execsum.html

I. Executive Summary

A. Highlights of the Notice of Proposed Rulemaking

NHTSA initiated this rulemaking with the publication of a Notice of Proposed Rulemaking (NPRM)(66 FR 38982, Docket No. NHTSA-2000-8572) on July 26, 2001. The NPRM proposed to require passenger cars, light trucks, multipurpose passenger vehicles, and buses with a gross vehicle weight rating of 10,000 pounds or less, except those vehicles with dual wheels on an axle, to be equipped with a tire pressure monitoring system (TPMS).

The agency sought comment on two alternative sets of performance requirements for TPMSs and proposed adopting one of them in the final rule. The first alternative would have required that the driver be warned when the pressure in any single tire or in each tire in any combination of tires, up to a total of four tires, had fallen to 20 percent or more below the vehicle manufacturer's recommended cold inflation pressure for the vehicle's tires (the placard pressure), or a minimum level of pressure specified in the standard, whichever was higher. (This alternative is referred to below as the four-tire, 20 percent alternative.) The second alternative would have required that the driver be warned when the pressure in any single tire or in each tire in any combination of tires, up to a total of three tires, had fallen to 25 percent or more below the placard pressure, or a minimum level of pressure specified in the standard, whichever was higher. (This alternative is referred to below as the three-tire, 25 percent alternative.) The minimum levels of pressure were the same in both proposed alternatives. The adoption of four-tire, 20 percent alternative would have required that drivers be warned of under-inflation sooner and in a greater array of circumstances. It would also have narrowed the range of technologies that manufacturers could use to comply with the new standard.

There are two types of TPMSs currently available, direct TPMSs and indirect TPMSs. Direct TPMSs have a tire pressure sensor in each tire. The sensors transmit pressure information to a receiver. Indirect TPMSs do not have tire pressure sensors. Current indirect TPMSs rely on the wheel speed sensors in an anti-lock braking system (ABS) to detect and compare differences in the rotational speed of a vehicle's wheels. Those differences correlate to differences in tire pressure because decreases in tire pressure cause decreases in tire diameter that, in turn, cause increases in wheel speed.

To meet the four-tire, 20 percent alternative, vehicle manufacturers likely would have had to use direct TPMSs because even improved indirect systems would not likely be able to detect loss of pressure until pressure has fallen 25 percent and could not detect all combinations of significantly under-inflated tires. To meet the three-tire, 25 percent alternative, vehicle manufacturers would have been able to install either direct TPMSs or improved indirect TPMSs, but not current indirect TPMSs.

B. Highlights of the Preliminary Determination About the Final Rule

NHTSA preliminarily determined to issue a final rule that would have specified a four-year phase-in schedule (1) and allowed compliance with either of two options during the phase-in, i.e., between November 1, 2003 and October 31, 2006. Under the first option, a vehicle's TPMS would have had to warn the driver when the pressure in one or more of the vehicle's tires, up to a total of four tires, was 25 percent or more below the placard pressure, or a minimum level of pressure specified in the standard, whichever pressure was higher. (This option is referred to below as the four-tire, 25 percent option.) Under the second option, a vehicle's TPMS would have had to warn the driver when the pressure in any one of the vehicle's tires was 30 percent or more below the placard pressure, or a minimum level of pressure specified in the standard, whichever pressure was higher. (This option is referred to below as the one-tire, 30 percent option.) The minimum levels of pressure specified in the standard were the same for both compliance options.

After the phase-in, i.e., after October 31, 2006, the second option would have been terminated, and the provisions of the first option would have become mandatory for all new vehicles. Thus, all vehicles would have been required to meet a four-tire, 25 percent requirement.

C. OMB Return Letter

After reviewing the draft final rule, OMB returned it to NHTSA for reconsideration, with a letter explaining its reasons for doing so, on February 12, 2002. In the letter, OMB stated its belief that the draft final rule and accompanying regulatory impact analysis did not adequately demonstrate that the agency had selected the best available method of improving overall vehicle safety.

D. Highlights of the Final Rule

In response to the OMB return letter, the agency has decided to divide the final rule into two parts. The first part is contained in this document, which establishes requirements for vehicles manufactured during the first three years, i.e., between November 1, 2003, and October 31, 2006, and phases them in by increasing percentages of production. The second part will establish requirements for vehicles manufactured on or after November 1, 2006.

The agency has divided the final rule into two parts because it has decided to defer its decision as to which long-term performance requirements for TPMS would best satisfy the mandate of the TREAD Act. This deferral will allow the agency's consideration of additional data on the effect and performance of TPMSs. From the beginning, the agency has sought to comply with the mandate and safety goals of the TREAD Act in a way that encourages innovation and allows a range of technologies to the extent consistent with providing drivers with sufficient warning of low tire pressure under a broad variety of the reasonably foreseeable circumstances in which tires become under-inflated.

1. Part One -- Phase-in (November 2003 through October 2006)

NHTSA has decided to require vehicle manufacturers to equip their light vehicles (i.e., those with a gross vehicle weight rating (GVWR) of 10,000 lbs. or less) with TPMSs and to give them the option for complying with either of two sets of performance requirements during the period covered by the first part of the final rule, i.e., from November 1, 2003 to October 31, 2006. The options are the same as those in the preliminary determination about the final rule.

Under the first set or compliance option, the vehicle's TPMS will be required to warn the driver when the pressure in any single tire or in each tire in any combination of tires, up to a total of four tires, is 25 percent or more below the vehicle manufacturer's recommended cold inflation pressure for the tires, or a minimum level of pressure specified in the standard, whichever pressure is higher. Under the second compliance option, the vehicle's TPMS will be required to warn the driver when the pressure in any single tire is 30 percent or more below the vehicle manufacturer's recommended cold inflation pressure for the tires, or a minimum level of pressure specified in the standard, whichever pressure is higher. (2)

The two compliance options are outgrowths of the alternative sets of requirements proposed in the NPRM. In response to comments confirming that current indirect TPMSs cannot meet the proposed three-tire, 25 percent under-inflation requirements, and in order to allow those systems to be used during the phase-in, the agency is adopting requirements for detection of one-tire, 30 percent under-inflation as the first option. For the second option, the agency is adopting requirements for detection of 4-tire, 25 percent under-inflation. Adopting those requirements, instead of the proposed requirements for four-tire, 20 percent under-inflation, will permit manufacturers to use either direct TPMSs or hybrid TPMSs, i.e., TPMSs that combine direct and indirect TPMS technologies. One TPMS supplier indicated the potential for developing and producing hybrid systems, although it also indicated that it did not currently have plans for doing so. The agency believes that the difference in benefits between TPMSs meeting four-tire, 20 percent requirements and TPMSs meeting four-tire, 25 percent requirements should not be substantial.

To facilitate compliance with the options, the rule phases them in by increasing percentages of production. Ten percent of a vehicle manufacturer's light vehicles will be required to comply with either compliance option during the first year (November 1, 2003 to October 31, 2004), 35 percent during the second year (November 1, 2004 to October 31, 2005), and 65 percent during the third year (November 1, 2005 to October 31, 2006). These percentages are the same as those in the preliminary determination about the final rule. The agency is allowing carry-forward credits for vehicles that are manufactured during the phase-in and are equipped with TPMSs that comply with the four-tire, 25 percent option. It is not allowing credits for TPMSs complying with the other option for the same reason that the agency is requiring manufacturers to provide consumers with information about the performance limitations of those systems.

The combination of the two compliance options and the phase-in will allow manufacturers to continue to use current indirect TPMSs during that period and ease the implementation of the TPMS standard. The agency notes that, for vehicles already equipped with ABS, the installation of a current indirect TPMS is the least expensive way of complying with a TPMS standard. The compliance options and phase-in will also give manufacturers the flexibility needed to innovate and improve the performance of their TPMSs. This flexibility will improve the chances that ways can be found to improve the detection of under-inflation as well as reduce the costs of doing so.

The owner's manual for vehicles certified to either compliance option will be required to include written information explaining the purpose of the low tire pressure warning telltale, the potential consequences of driving on significantly under-inflated tires, the meaning of the telltale when it is illuminated, and the actions that drivers should take when the telltale is illuminated. In addition, the owner's manual in vehicles certified to the one-tire, 30 percent option will be required to include information on the inherent performance limitations of current indirect TPMSs because the agency anticipates that most indirect TPMSs installed to comply with that option will exhibit those limitations and because a vehicle owner survey indicates that a significant majority of drivers would be less concerned, to either a great extent or a very great extent, with routinely maintaining the pressure of their tires if their vehicle were equipped with a TPMS. Under both compliance options, the TPMS will be required to have a low tire pressure-warning telltale (yellow).

2. Part Two -- November 2006 and Thereafter

Beginning November 1, 2006, all passenger cars and light trucks, multipurpose passenger vehicles, and buses under 10,000 pounds GVWR will be required to comply with the requirements in the second part of this final rule. The agency will publish the second part of this final rule by March 1, 2005, in order to give manufacturers sufficient lead time before vehicles must meet the requirements.

In anticipation of making the decision in part two of this final rule about the long-term requirements, the agency will leave the rulemaking docket open for the submission of new data and analyses. The agency also will conduct a study comparing the tire pressures of vehicles without any TPMS to the pressures of vehicles with TPMSs that do not comply with the four-tire, 25 percent compliance option. When completed, it will be placed in the docket for public examination. After consideration of the record compiled to this date, as supplemented by the results of the tire pressure study and any other new information submitted to the agency, NHTSA will issue the second part of this rule by March 1, 2005.

Based on the record now before the agency, NHTSA tentatively believes that the four-tire, 25 percent option would best meet the mandate in the TREAD Act. However, it is possible that the agency may obtain or receive new information that is sufficient to justify a continuation of the compliance options established by the first part of this final rule, or the adoption of some other alternative.

E. Summary Comparison of the Preliminary Determination and the Final Rule

The primary difference between the preliminary determination and the final rule is one of timing, instead of substance. The options and percentages of production for the phase-in years are unchanged. (3) The final rule does differ from the preliminary determination in the timing of the agency's decision about the performance requirements for the years following the phase-in period.



Summary Comparison of the Preliminary Determination and the Final Rule
Preliminary Determination Final Rule
Application Passenger cars, trucks, multipurpose passenger vehicles, and buses with a GVWR of 10,000 pounds or less, except those vehicles with dual wheels on an axle Same
Short-term
(11/1/03 - 10/31/06)
Compliance
Options Option 1: TPMS must warn the driver when the pressure in any single tire or in each tire in any combination of tires, up to a total of four tires, has fallen to 25 percent or more below the vehicle manufacturer's recommended cold inflation pressure for the tires, or a minimum level of pressure specified in the standard, whichever pressure is higher.
Option 2: TPMS must warn the driver when the pressure in any single tire has fallen to 30 percent or more below the vehicle manufacturer's recommended cold inflation pressure for the tires, or a minimum level of pressure specified in the standard, whichever pressure is higher. Same

Same



Same
Phase-in
Schedule 10% of a vehicle manufacturer's light vehicles will be required to comply with either compliance option during the first year (November 1, 2003 to October 31, 2004), 35 percent during the second year (November 1, 2004 to October 31, 2005), and 65 percent during the third year (November 1, 2005 to October 31, 2006). Same
Long-term
(11/1/06 & thereafter)
Performance
Requirements TPMS must warn the driver when the pressure in any single tire or in each tire in any combination of tires, up to a total of four tires, has fallen to 25 percent or more below the vehicle manufacturer's recommended cold inflation pressure for the tires, or a minimum level of pressure specified in the standard, whichever pressure is higher. Decision to be made by March 1, 2005


Hope this helps.

 

Helpful, but wordy.

 

When a new sensor is installed it has to be recalibrated with a magnet. I believe that the process is the same as it was for a C5.

 

Thanks.

 

Don't shoot the messenger.

I report, you decide.

 

My right rear tire sensor went out after 34 miles. Took it to dealer three weeks ago to have it checked out. He ordered new part but still not here.

 

My front right tire mon is reading xxx .presure is 31 lbs . It went out when I was over 100mph in Utah . Hate to take it to dealer.

 

EHS,
Will the use of Fix-a-Flat cause problems with tire pressure monitors?

 

 

I have always and am used to checking the tires the old fashion way and have been lucky as I usually discover my leaks or nails, sources of air leaks.
Where exactly are these sensors for the tires located? They seem to go out alot are they located in the tire so if you scrub your wheels against the curb that can cause a malfunction?

 

Yes, they have a little hole to measure the air pressure in the tires. The "fix-flat" juice gums them up and makes them useless.

That's why I dive for the gas station when I have a low pressure warning (only happened once in 55,000 miles so far). But it was worth it right there.

 

I also check the old fashioned way, but the sensor is nice when you're on the road and you start getting a flat. That way, you don't have to stop eveyr 15 minutes to check the tire pressure -- which is about how much time I had when the low pressure warning went off to get to a gas station -- I could minitor the pressure right down to 5 lbs.

They are located on they inside of the valve stem, and look like this:









Here's basically how the whole thing works (pardon some Corvette/GM terminology, but I think it's the thought that counts):




1. The car senses the ambient temperature and barometric pressure through the main computer (PCM on the C5).

2. There is a remote radio frequency pickup module that accepts the data from each sensor (the sensors have to be programmed for their particular wheel location).

3. A little math, and by comparing the ambient outside air pressure with that inside the tire, throw in the temperature correction factor, and you should come up with the actual psi in the tire.

4. The sensors were notoriously inaccurate -- Schrader claims 2%, but 5% one way or another is more real world for pre-2002 C5s. The newere one's are more accurate: www.schraderelectronics.com

5. To remove the sensor, unscrew the nut and let the senor fall into the tire/wheel. Break the bead, try not to catch the senor in the process, and then reach in an take out the sensor. They are mounted in reverse; put the tire on the wheel, screw in the sensor/stem, then set the bead and inflate the tire.

6. Critical to remounting the sensors is the tiny little "O" ring that makes the seal with the wheel. They can be reused if not damaged, but they may not fit the profile on some aftermarket wheels -- so either check carefully, or get slightly thicker "O" rings. Normally, they should work.

7. Finally, here is the punch line on aftermarket wheels. Be sure to check that not only will the wheel and tire combination fit the car, but also that the tire sensors will fit in the new wheel. The issue isn't so much the overall height, as the edge profile of the wheel (see the pictures above).

So, the bottom line. Yes, if you hit the curb hard enough to srew up the valve stem, you could also screw up the sensor.

 

Yup. In this order. LF,RF,RR,LR. Otherwise you will get false PSI Readings.

Fix a Flat=BAD

 

good post
thanks for all the info

 

EHS,

Thanks for that explanation. Very helpful. A couple of further questions on this subject - if I were to run a second set of wheels/tires for autox, would I need to set them up with sensors, or would leaving them off altogether prompt some sort of an error message? Relatedly, when the street wheels/tires go back on, would the sensors have to be recalibrated?