[DFrantz]

Volvo one-ups you. They make it a guessing game to determine if it’s even accurate. In my experience, it’s been wrong far more times than right.

I've never seen them inaccurate that there was an issue.... other than where it always says low even if it's over inflated. But that's just crap programming, where the programmer assumed if there was an incorrect pressure that it must be low. But any time I've seen the light come on I've found one of the tires to have a pressure issue.

 

[vonogo]

I honestly don't how ITPMS is legal, even the CFR says they're ****. Skip to the bold.

https://www.nhtsa.gov/sites/nhtsa.gov/files/fmvss/TPMSfinalrule.pdf

"Safety Problem
A. Infrequent Driver Monitoring of Tire Pressure
B. Loss of Tire Pressure Due to Natural and Other Causes
C. Percentage of Motor Vehicles with Under-Inflated Tires
D. Consequences of Under-Inflation of Tires
1. Reduced Vehicle Safety - Tire Failures and Increases in Stopping Distance
2. Reduced Tread Life
3. Reduced Fuel Economy

A. Indirect TPMSs
Current indirect TPMSs work with a vehicles ABS. The ABS employs wheel speed sensors to measure the rotational speed of each of the four wheels. As a tires pressure decreases, the rolling radius decreases, and the rotational speed of that wheel increases correspondingly. Most current indirect TPMSs compare the sums of the wheel speeds on each diagonal (i.e., the sum of the speeds of the right front and left rear wheels as compared to the sum of the speeds of the left front and right rear wheels). Dividing the difference of the sums by the average of the four wheels speeds allows the indirect TPMS to have a ratio that is independent of vehicle speed. This ratio is best expressed by the following equation: [(RF + LR) (LF + RR)/Average Speed]. If this ratio deviates from a set tolerance, one or more tires must be over- or under-inflated. A telltale then indicates to the driver that a tire is under-inflated. However, the telltale cannot identify which tire is under-inflated. Current vehicles that have indirect TPMSs include the Toyota Sienna, Ford Windstar, and Oldsmobile Alero. Current indirect TPMSs must compare the average of the speeds of the diagonal wheels for several reasons. First, current indirect TPMSs cannot compare the speed of one wheel to the speeds of the other three wheels individually or to the average speed of the four wheels. During any degree of turning, the outside tires must rotate faster than the inside tires. Thus, all four wheel speeds deviate significantly when the vehicle is in a curve or turn. If a current indirect TPMS compared each individual wheel speed to the average of all four wheels speeds, the system would provide a false alarm each time the vehicle rounded a curve or made a turn. The same would be true if the indirect TPMS compared each individual wheel speed to the speed of the other three wheels individually. Since the outside wheels would rotate much faster than the inside wheels in a curve or turn, each outside tire would appear to be under-inflated when compared to an inside tire. Current indirect TPMSs also cannot compare the speeds of the front wheels to the speeds of the rear wheels because in curves, the front and rear wheels (on both sides of the vehicle) rotate at different speeds. This is primarily due to the fact that the front axle is steerable and follows a different trajectory than the rear axle. As a result, current indirect TPMS must compare a tire from each side and a tire from the front and rear axles to factor out the speed difference caused by curves and turns. Thus, current indirect TPMSs must compare the average speed of the diagonal wheels. The VRTC tested four current ABS-based indirect TPMSs. None met all the requirements of either alternative proposed in the NPRM. All but one did not illuminate the low tire pressure warning telltale when the pressure in the vehicles tires decreased to 20 or 25 percent below the placard pressure. The VRTC determined that since reductions in tire diameter with reductions in pressure are very slight in the 15-40 psi range, most current indirect TPMSs require a 20 to 30 percent drop in pressure before they are able to detect under-inflation. The VRTC also concluded that those thresholds were highly dependent on tire and loading factors. The VRTC also found that none of the tested indirect TPMSs were able to detect significant under-inflation when all four of the vehicles tires were equally under-inflated, or when two tires on the same axle or two tires on the same side of the vehicle were equally under-inflated. However, the VRTC did find that indirect TPMSs could detect when two tires located diagonally from each other (e.g., the front left and back right tires) became significantly under-inflated."

 

[Ultrarunner511]

I honestly don't how ITPMS is legal, even the CFR says they're ****. Skip to the bold.




https://www.nhtsa.gov/sites/nhtsa.gov/files/fmvss/TPMSfinalrule.pdf



"Safety Problem
A. Infrequent Driver Monitoring of Tire Pressure
B. Loss of Tire Pressure Due to Natural and Other Causes
C. Percentage of Motor Vehicles with Under-Inflated Tires
D. Consequences of Under-Inflation of Tires
1. Reduced Vehicle Safety
2. Tire Failures and Increases in Stopping Distance
3. Reduced Tread Life Reduced Fuel Economy

A. Indirect TPMSs
Current indirect TPMSs work with a vehicles ABS. The ABS employs wheel speed sensors to measure the rotational speed of each of the four wheels. As a tires pressure decreases, the rolling radius decreases, and the rotational speed of that wheel increases correspondingly. Most current indirect TPMSs compare the sums of the wheel speeds on each diagonal (i.e., the sum of the speeds of the right front and left rear wheels as compared to the sum of the speeds of the left front and right rear wheels). Dividing the difference of the sums by the average of the four wheels speeds allows the indirect TPMS to have a ratio that is independent of vehicle speed. This ratio is best expressed by the following equation: [(RF + LR) (LF + RR)/Average Speed]. If this ratio deviates from a set tolerance, one or more tires must be over- or under-inflated. A telltale then indicates to the driver that a tire is under-inflated. However, the telltale cannot identify which tire is under-inflated. Current vehicles that have indirect TPMSs include the Toyota Sienna, Ford Windstar, and Oldsmobile Alero. Current indirect TPMSs must compare the average of the speeds of the diagonal wheels for several reasons. First, current indirect TPMSs cannot compare the speed of one wheel to the speeds of the other three wheels individually or to the average speed of the four wheels. During any degree of turning, the outside tires must rotate faster than the inside tires. Thus, all four wheel speeds deviate significantly when the vehicle is in a curve or turn. If a current indirect TPMS compared each individual wheel speed to the average of all four wheels speeds, the system would provide a false alarm each time the vehicle rounded a curve or made a turn. The same would be true if the indirect TPMS 49 compared each individual wheel speed to the speed of the other three wheels individually. Since the outside wheels would rotate much faster than the inside wheels in a curve or turn, each outside tire would appear to be under-inflated when compared to an inside tire. Current indirect TPMSs also cannot compare the speeds of the front wheels to the speeds of the rear wheels because in curves, the front and rear wheels (on both sides of the vehicle) rotate at different speeds. This is primarily due to the fact that the front axle is steerable and follows a different trajectory than the rear axle. As a result, current indirect TPMS must compare a tire from each side and a tire from the front and rear axles to factor out the speed difference caused by curves and turns. Thus, current indirect TPMSs must compare the average speed of the diagonal wheels. The VRTC tested four current ABS-based indirect TPMSs. None met all the requirements of either alternative proposed in the NPRM. All but one did not illuminate the low tire pressure warning telltale when the pressure in the vehicles tires decreased to 20 or 25 percent below the placard pressure. 29 The VRTC determined that since reductions in tire diameter with reductions in pressure are very slight in the 15-40 psi range, most current indirect TPMSs require a 20 to 30 percent drop in pressure before they are able to detect under-inflation. The VRTC also concluded that those thresholds were highly dependent on tire and loading factors. The VRTC also found that none of the tested indirect TPMSs were able to detect significant under-inflation when all four of the vehicles tires were equally under-inflated, or when two tires on the same axle or two tires on the same side of the vehicle were equally under-inflated. However, the VRTC did find that indirect TPMSs could detect 50 when two tires located diagonally from each other (e.g., the front left and back right tires) became significantly under-inflated."

None of that surprises me. Volvo missed their “safety” goal by seeking cheaper ways out. I’d take any issue on direct TPMS any day - including dead batteries. Rather than the garage Volvo has thrown on these cars. 3 of 4 SPA’s we’ve owned have given false alerts. Knock on wood the 2023 has been flawless. 🤞

 

[BigBang]

You can enable it on Sensus car with Orbit. You just need the sensors, don't need to program them to the car.

I've never heard of that option
What sensors do you use, I had several models on different vehicles and of course the new sensors must be programmed to be functional

 

[BigBang]

I've never seen them inaccurate that there was an issue.... other than where it always says low even if it's over inflated. But that's just crap programming, where the programmer assumed if there was an incorrect pressure that it must be low. But any time I've seen the light come on I've found one of the tires to have a pressure issue.

Only happened to me once, I got a warning that my left rear tire was low, I checked and it was 27psi instead of 35

 

[DFrantz]

So we're using an article that references an Oldsmobile as a current model? Every problem they mention has a programmable solution. What was the last Olds 2004?

 

[Turbovagn]

Yeah, that article is at least 20 years old. I'm kinda with D on this one.

I have no gripes with the ITPMS. Anecdotally, it worked perfectly when I got a nail in my tire. Very slow leak and it caught it when the pressure reached low 30s (down from 39).

Nice to not have any sensors to replace. I do see how it could potentially lead to people to ignore their tire pressure for longer, though basic car maintenance seems be highly neglected in general by many these days.

 

[BigBang]

To me, the situation is much worse that Volvo does not use brake pad wear sensors

 

[DFrantz]

To me, the situation is much worse that Volvo does not use brake pad wear sensors

Yeah, I suppose most states don't have annual inspection, not sure about other countries, and most people don't inspect themselves (which is the whole value of TPMS too....)

 

[richardGG24]

I've never heard of that option
What sensors do you use, I had several models on different vehicles and of course the new sensors must be programmed to be functional

Autel MX universal sensors, they must be programmed with Autel TPMS tool.

Shrader 28304 is plug and play, no programming needed, just hit the calibrate button and car will take care of the rest.

 

[DFrantz]

Don't forget to rebalance when adding the sensors.

 

[VxF]

DFrantz, I think it really comes down to - does it, or does it not, work. And here we seem to have very different experiences.
I have over 200k miles on SPA XC90s. Three owned cars, tons of loaners because, well, we are talking about Volvos. It systemically did not work. Granted, I am probably an "extreme" user. I drive into mountains regularly, with the added issues of dramatic changes in temps and air pressure. I change tires often, because, well, I value safety - so I do use winter wheels. IT JUST DOES NOT WORK. I hit potholes and had a tires completely shred without the system triggering. I had plenty of 10+ psi drops not detected, where I feel the tire being off before the system triggers. I also had DOZENS of false positives, in all sorts of conditions.
Indirect systems can work. They are never great, but they can work.
Volvo's does not.
Does it occasionally get it right? Sure. I have anecdotes of it actually working, even identifying the correct tire once.
But what is acceptable, for a safety device? Is 95% of the time ok? Is it 90? What I am trying to say, you need to have confidence in a safety device. You can't trust this crap.

 

[399613]

I like gauges, dipsticks,TPMS and anything else that can allow the driver to see things before a bigger failure occurs. A climbing temp gauge can alert the driver that a issue is about to happen before it overheats. The color of oil can show you if there is a water intrusion issue happening before bearing damage occurs. Lower engine oil pressure is also a helpful telltale. Same goes for a tranny, pink is good but brown is not. I am a very hands on car guy rebuilding and restoring many cars and the more information that I have at my disposal the better. As far as TPMS its nice that it alerts me immediately that my wifes tire is going flat especially after my car sits overnight and it's also much easier to fix with my floor jack, compressor and tools then driving a few blocks away and then alerted with a flat tire. I have no issue with failsafe systems as they certainly work but sometimes maybe too late. Didn't a Volvo have a car fire recently and the driver was alerted to get out of the car because battery temperature was too high and the good news they got out safely but maybe a gauge or just a LED display showing battery temp rising may have stopped the total loss of the car and the very close call to the lives of the occupants.

 

[BigBang]

Yeah, I suppose most states don't have annual inspection, not sure about other countries, and most people don't inspect themselves (which is the whole value of TPMS too....)

It is not an inspection, but the practical side of using the vehicle
All modern cars Audi, VW, BMW, MB, Porsche, Peugeot, Citroen... have a brake pad wear sensor.

Just like 99% of cars in the world have an engine temperature gauge, Volvo doesn't have that either
Savings or something else

When I go for an oil change once a year or every 15,000 km, what if the service technician tells me that my brake pads are 70% worn, and that I need to replace them soon?
Should I replace immediately or should I check for wear every 7 days?
I understand that, but 60% of drivers don't know anything about it, do you think my wife should look at how worn the brake pads are?

 

[BigBang]

Autel MX universal sensors, they must be programmed with Autel TPMS tool.

Shrader 28304 is plug and play, no programming needed, just hit the calibrate button and car will take care of the rest.

Great news, I would still like to see how it looks in your Volvo car with the Sensus system

 

[vonogo]

So we're using an article that references an Oldsmobile as a current model? Every problem they mention has a programmable solution. What was the last Olds 2004?

Would I rather have a direct readout in the dash that is accurate within 1psi and spend less than a $100 to get it or would I like to play guess the press until I spend the time to unscrew every cap and check every pressure 12 times a year. Plus your hands get dirty so picking your nose afterwards is out the door.

Bottom line, TREAD was enacted for the above reasons - keeping all tires properly inflated, and ITPMS still fails at that.

 

[richardGG24]

Great news, I would still like to see how it looks in your Volvo car with the Sensus system

 

[BigBang]

View attachment 233477

Great, good to know that option exists

 

[dbphillips]

Dumbass that I am, I was driving around with all four tires 6.5psi low.

It's not you, it's the stupid indirect model. The most typical result is all tires slowly lose pressure equally.

Just upcharge for direct, it's not rocket science...

 

[snowfun]

@richardGG24 - thanks for the information. How sure are you the Schrader system will work on the Sensus XC60? From what I see from parts stores, these are the applicable Volvo models: S60, S80, V60, V90, XC90.