Speed Volume option on radio
 

OK, I give up.

On the standard radio menu there is an option for "speed volume" numbers 0-7. I can not find any reference in the owners manual for this. While experimenting with the max setting there is no change in volume.

I've had GM cars and the SCV (speed controlled volume) always worked.

-R

Re: Speed Volume option on radio
 

In the Nav version, this is called AVC (Automatic Volume Control). Changing the settings shouldn't produce an instantaneous response, but will boost the volume as interior noise increases. I'm guessing that 'speed volume' is a simpler version that increases volume as speed increases.

Re: Speed Volume option on radio
 

I have a 06 FEH with a 6 CD/SAT radio (NO NAV), My radio has a speed volume menu for 0-7 volume settings. It did not work so I took it in to have it fixed. The SA said I had a bad radio and ordered a new one. It took 4 weeks but it finally came in. (4 weeks is another story). After a couple of hours with the car the SA came to me and said it still was not working and would need to keep the car for testing and asked if I would leave it over night.

The next day he told me my FEH did NOT have this feature even though the radio acted like it should have it. The tech ran an OASIS and found OASIS # 19400 for 2005-2007 FEH and MMH. He gave me a copy of it and it says it needed a circuit to make it work. It said n part "...also a speed signal input circuit (679 GY-BK) present at pin 14 of c240a of the audio unit. If this circuit is not present in c240a the radio is operating as designed and no repairs are necessary." He also gave me a HVBoM for my vin. It has the features and codes built into my car. Under audio it has a code IGHAA which says "Less radio control auto volume".

Bottom line here is I'm told the car does't have the wiring (senor?) to make the speed volume work.

Just my experience with speed volume.

Re: Speed Volume option on radio
 

Must depend on what options you have... I have the NAV option and there is a speed volume control on it and it certainly works... In fact when set wrong its fairly annoying because it can ram the volume pretty loud if you just crawl forward a bit at an intersection.

Re: Speed Volume option on radio
 

Makes sense, thanks.

Anyone have the pin outs to the radio? I found this scrap of info on the net but need to verify it: "Pin 14 679(GY/BK) Vehicle speed signal (+) to powertrain control module"

Seems to be related to the ABS system. If the NAV systems have the feature enabled then the signal must be available.

-R

Re: Speed Volume option on radio
 

Its definitely enabled on the NAV systems... that signal is also used to disable access to some of the NAV functions so you aren't adjusting them in a moving vehicle.. In fact in the discussion for it there is a fair amount of information on the harness and diagrams so people could disable it. Look in the threads on this site for the NAV system and the ones on adding in an iPod... they both have info on the wiring harness. However I think I read that the wiring harness for the NAV vehicles is significantly different than the non NAV system FEH's. It sounds counterintuitive because you'd think a company wouldn't want to have a whole bunch of different parts for different options if it could be avoided... but you might find that even if a NAV vechile has the VSA (I think thats what the signal is called) yours might not have the same signal available.

Re: Speed Volume option on radio
 

The signal is available and can be used. Now I need a day to find it.

-R

From the Escape/Mariner Hybrid Modifier Guide...

Vehicle Speed Signal

Note: If non-OEM tires are mounted on the vehicle, the pulse per mile frequency will change.

Note: Any device connected to the vehicle speed signal (VSS) circuit will require a high impedance of at least 1 megaohm. If this speed signal is compromised (by using a device with low impedance), the navigation system may not be able to show the correct position of the vehicle as accurately.

The vehicle speed signal (VSS) is sent from the brake system control module to the navigation system through circuit 679 (GY/BK). If the vehicle is not equipped with a navigation system, circuit 679 (GY/BK) ends in connector C210 pin 5. With OEM tires on the vehicle, the signal is 31924 pulses per mile.

Re: Speed Volume option on radio
 

Notice it says the if there is no NAV the signal ENDS in connector C210 pin 5. I'm guessing that means the harness that goes to the back of the radio doesn't have a pin that is VSS unless you have a NAV. You probably have to go back to the computer (wherever connector C210 is) to tap into it there... So you might have to run a wire through the firewall (where is the CPU on this thing? I'd guess in the engine compartment but its a guess.... there are a ton of wires leading from the engine compartment to the firewall as I recall.

Re: Speed Volume option on radio
 

On a somewhat unrelated note....I wonder if some of the people that complain that their NAV system is so far off (when it has no fix ) have their tire pressures up at 40PSI or more and that is throwing off the VSS distance sensor so the NAV can't guess how far they've gone... also wonder if that throws off their MPG numbers reported by the NAV.

Re: Speed Volume option on radio
 

Hmmm, I was just thinking the same when you posted this. If I over-inflate my tires I may actually get better mpg than either the nav system or the odometer is telling me.

There's an initial benefit due to the reduced rolling resistance of the harder tire (which will show up in mpg calcs) but a secondary bump from the increased effective diameter. If each revolution of the wheel carries me just 1% further then my mpg will be understated by 1%. That's a good thing in terms of the environment, less good if I want to know accurately what I'm getting.

Re: Speed Volume option on radio
 

The tire pressure in your tires DOES NOT change the distance (perimeter) around the tire!!!!
( at least not by any measureable amount, so for all practical purposes, stays the same )

Say the perimeter of the tire is normally 2000mm. Flat = 1999.9mm. 45psi = 2000mm.
Only the shape changes with pressure changes.
The more air pressure you have, the closer to a circle with 2000mm circumference you have. Less air = a longer flat spot on the bottom.
No matter what pressure you have, the distance around the tire, and your MPG or odometer is NOT affected.
( As the tire tread wears off, your tires will get slightly smaller. )

-John


P.S. It may help to visualize your tire like a tank's tread. No matter how many rollers the tank has, or the shape of the tank, the tank tread length never changes to make one revolution. The distance traveled for your tire tread to make one revolution NEVER changes.

Re: Speed Volume option on radio
 

You're right of course, John, though it's counter-intuitive.

Thanks,

Re: Speed Volume option on radio
 

That does make the presumption that the tread on a tire cannot stretch... which, now after I've thought about it, is likely true since all tires are steel belted these days. I doubt the steel belt would have much give in it at all.

Lacking the steel belt the rubber could stretch SOME.... but probably not much since the tread rubber is pretty thick. Bike tires for example definitely have different circumferences depending on inflation pressure, which is why you have to adjust the speedometers for distance if they use a magnet to count tire revolutions (it says that in the manual I have for mine). But of course Bike tires aren't steel belted and are a heck of a lot thinner.

I hadn't thought of the steel belt when I posted and was thinking of that bike speedometer at the time.

Re: Speed Volume option on radio
 

I have the NAV radio, and I noticed that the volume will "blast" quite loud, for a split second, when I am going very slow. For example, when I am pulling into the garage, and I am about 1/2 in, the radio's sound will "blast" and then return back to the expected volume level. It will also do this, sometimes, just as I am just about to come to a full stop at a red light or signal.

From your posting, I wonder if this is because of the AVC (Automatic Volume Control) setting? I had been thinking it was simply a bug in the firmware which caused the momentary "blast".

Re: Speed Volume option on radio
 

It is... I have set mine very low because I've experienced the same blast. If you set the AVC all the way to the left you'll find the blast effect goes away. Actually, it still is a firmware issue in the sense that whomever programmed the darn thing should have made it use a running average of speed rather than the instantaneous speed it appears to be using. Apprently it gets a spike in the readings sometimes and it responds and blows your ears off.

Re: Speed Volume option on radio
 

That does make the presumption that the tread on a tire cannot stretch

That was my mistake. I was thinking of the extreme case of Top Fuel dragsters. They use non-steel belted tires inflated to around 6psi and the centrifugal force greatly increases the tire O/D at high revs, acting rather like a CVT.

Compare stationary to rotating:
http://www.tootees.com/rdscbac.jpg
http://212.227.92.102/img/11129/wm/pd404629.jpg

Definately a change in diameter.

Sorry it's completely off-topic, I'll shut up now.

Re: Speed Volume option on radio
 

If this is indeed true, then how do many manufacturers (including some Ford models) utilize the ABS sensors instead of actual air pressure sensors to operate their TPMS systems?

For example, this was taken from from the 2002 Windstar shop manual section 204-04:

"The Low Tire Warning (LTW) system detects differences in inflation pressures in one or more tires. The system uses the ABS wheel speed sensors to monitor the rolling radius of the wheel and tire assemblies."


A few other vehicles that use this approach include 2001 to 2003 Ford Windstar, 1997-2002 Buick Park Avenue, 1999-2003 Buick Century & Regal, 2002-2003 Buick LeSabre, 2003 Buick Rendezvous & Aztek, 2000-2003 Chevy Impala & Monte Carlo, 1999-2002 Chevy Alero, 1999-2002 Pontiac Grand Am, 1997 - 2003 Pontiac Grand Prix, 2000 - 2003 Pontiac Bonneville, and 2001-2003 Oldsmobile Aurora. Source: http://www.aa1car.com/library/tire_monitors.htm

Re: Speed Volume option on radio
 

So maybe I was right and I gave up too soon.

Its been rolling around in my head for a while now. Even with a steel belt the MIDDLE of the flat belt can likely bow in or out changing the diameter of the tire slightly.

As for the tank tread comparison.... um.. tank treads aren't Pnuematic. Clearly as you fill a balloon with air the diameter around the ballon increases. A rubber tire is like a ballon except for the fact that its thicker and has a steel belt. from the info above it appears that even a steel belt will give some. 40PSI provides a significant amount of force when you multiply 40 times the area of the inside of the tire in square inches! All that force is pushing outward against the tire rubber trying to maintain shape.

If you can measure (even inaccurately) tire pressures using the speed of rotation, the distance around is not constant with air pressure.

Re: Speed Volume option on radio
 

TeeSter, I have to agree with you.

The tank tread analogy works well in a theoretical/perfect world, but it's nowhere near accurate when other variables (such as the rubber compound expanding, compressing, and slipping against the road surface - among others) are introduced in real world conditions.

Anyone that's every driven a 4WD truck with a locking front axle knows only too well how even a minor side-to-side variation in air pressure will induce a major pull to the side with lower pressure.

Re: Speed Volume option on radio
 

Don't NASCAR crews alter their air pressures left side to right side to make the inner wheels a slightly smaller diameter so the car turns easier as well?

Re: Speed Volume option on radio
 

Correct again! They refer to it as "stagger". I believe it had a more pronounced on the handling back in the bias ply days. It may still come into play on the radials used in Nascar today...although to a somewhat lesser degree than with bias ply tires. But please don't quote me on this since I don't follow Nascar and I also don't claim to be a tire expert.

Re: Speed Volume option on radio
 

Re: Speed Volume option on radio
 

Again, not comparing apples to apples.
The system of using ABS to "indirectly" measure tire pressure status will only tell you when there is a gross change in tire shape. The only thing this method is good for is telling you when your tire is FLAT. And if you need a sensor for that, then you are an idiot.

The tire circumference on modern passenger tires changes by less than 1mm ( out of more than 2000mm ) at any pressures between 10psi and 60psi. So in theory, the tire size changes. In reality, the change is too small to measure, or to have any mentionable effect on speedometers or odometers. I didn't know you guys wanted to talk "microns". If that's the case, then the length of your vehicle changes with speed also, as Einstein predicted, as the atoms get spread out by 0.00000000000000001mm when you travel fast... Geez... can we come back to what actually matters now?

Again, don't take my word for it. GO OUT AND MEASURE!
-John

Re: Speed Volume option on radio
 

There is a GM website that discusses the system mentioned....

http://www.gm.com/company/gmability/...m/sensing.html

it triggers at 10psi lower than normal.... thats when it triggers, not necesarily what it can measure. So its at least capable of seeing a tire thats 10psi low but is probably a bit better than that. Thats not highly accurate BUT its FAR from FLAT. Many people are raising theirs by 10psi or more.

Theres a little demo of what too little air looks like on a tire at
http://www.safercar.gov/Tires/pages/...adingCheck.htm

You have to go pretty low to say its "flat".

Looking at that last link... and dropping the pressure to 50%.... (more than 10PSI) the tire looks down a bit but you wouldn't have to be an IDIOT to think it was okay. At 70% it would be down more than 10PSI... looks pretty decent at that level. I guess I'm an idiot.

Oh... whats with the need to YELL

It was categorically denied that there was ANY change in tire diameter. All thats been pointed out is that statement is NOT true, there is a small change. And apprently it IS actually measureable at changes in pressure levels of 10PSI and maybe less.

Relax a bit... it's just a discussion.

I wasn't saying it was HUGE or anything myself. I just thought there should be a difference and wondered aloud how significant it would be.

Re: Speed Volume option on radio
 

They do this for stability reasons. Tire pressure changes the height of the car on one side, making it more stable on banked curves. I suspect they only do this on oval or circular tracks! ;) They also have "specialty" tires, unlike the ones on the FEH.

Re: Speed Volume option on radio
 

1) Drive a real 4WD truck with a locking front axle with only a 5 psi variance between the front tires and you'll notice a very definite pull to the side with the lower pressure. This is due to the reduced dynamic circumference of the tire with no differential action to compensate for it. If you unlock the hubs the pull will be gone. A difference in height would not be affected by switching from a locked (no differential action) axle to a fully open one.

2) You're asking everyone else to "prove otherwise". TeeSter and I have both providing sources of our information, but you've yet to tell anyone where you're getting your "facts" from. Please feel free to share them with us.

3) TeeSter, I hope you spend your $1,000 gift wisely.

Re: Speed Volume option on radio
 

#1 No, it is due to the fact that the tire with lower pressure has a larger contact patch with the ground, more square inches on the ground, and more grip with the road surface, so it can pull harder. Circumference stays the same, to within 1mm or less. ( unless you have some really cheap tires, perhaps )

#2 Real world experience, plus 2 science degrees and 1 engineering degree. Passenger road tires are just too stiff to stretch like you seem to think they do.

#3 I BEG you to go out and measure the circumference of a tire on your FEH with 20psi and 40psi, before posting further. I promise they will be the same to less than 1mm.

Can anyone, an administrator perhaps, copy and paste the tire messages only to a new thread? It appears we have gotten terribly off topic of the thread title.

Re: Speed Volume option on radio
 

Real world, actual data, measured with stock Continental EcoPlus tires that came as standard equipment on a 2005 Ford Escape Hybrid.

>At 50 psi Tire Circumference = 2100 mm or 82.66 inches
>At 35 psi Tire Circumference = 2100 mm or 82.66 inches
>At 25 psi Tire Circumference = 2100 mm or 82.66 inches
>At 20 psi Tire Circumference = 2099 mm or 82.64 inches
>At 15 psi Tire Circumference = 2098 mm or 82.60 inches

The following is a description of the contact patch:

>Contact patch at 50 psi = 11,000 sq.mm or about 18 sq.in.
>Contact patch at 35 psi = 16,000 sq.mm or about 25 sq.in.
>Contact patch at 15 psi = 38,500 sq.mm or about 60 sq.in.

Ok, at 50psi, we travel 82.66 inches per revolution.
After 1 million revolutions, we will travel 1304.60 miles.

At 20psi ( probably unsafe ) we will travel 1304.30 miles after those same, 1 million revolutions.

Since most people drive in the 25psi to 50psi ranges, there is NO over/under reporting on the speedometer or odometer.

-John:shade:

Re: Speed Volume option on radio
 

Whoa!

Let cool heads prevail, please. I know that this forum has some great knowledgeable contributors. Let's not digress and keep to the conversation so we can get the best out of the technology we "all" chose.

I will be investigating the Speed Volume that this thread was originally started. I see that there may be another need for a Odometer Accuracy thread. If so, then please start one. As a new contributor, if we can keep to the subject, this will be a great source of information for anyone who has deemed the FEH as a superior choice (not to knock others as they seem to have some good ideas :P ).

IMHO, I have seen some great forums shot to heck and become unusable because of this.

-R

Re: Speed Volume option on radio
 

Unfortunately, all of these static measurements fail to address how an ABS sensor can be used to determine the difference in dynamic tire diameter and circumference to infer a change in air pressure. The only way this can be accomplished is if the tires are turning at different speeds. When travelling straight, this means their effective diameters/circumferences are clearly different. Or am I missing somthing obvious here?

Sorry, but tire pressure clearly does affect the effective diameter and circumference of a tire. "Real world experience, plus 2 science degrees and 1 engineering degree" does not mean you're always right. Can you possibly provide a single unbiased outside source of data to support your position? (Even Einstein was wrong at times.)

Re: Speed Volume option on radio
 

A few things. #1 mathmatically, terms like "diameter, radius, circumference" only apply to circles. Your tires are not circles. So all the mathmatical formulas you are used to from High School really don't apply. I think this is skewing some perceptions. #2 are you trying to say the size of the tire is different when rolling vs. "static". Ridiculous. #3 ABS "inferences" could only work when there is a gross under-pressure, and only when you apply the brakes. Again, a foolhearty system, experimented with perhaps, but not a good system, and not as reliable as stated. Sounds like a cheap "scam" for manufacturers to "technically" meet Federal requirements (barely) without investing additional $. #4 yes, you are missing something, and you are not alone, so don't feel bad. There is no such thing as "effective circumference". Only a "perimeter" around the tire, which has a definite length, that does not change by more than 1mm or 2mm of "stretching". EVER. #5 Quit the mind games and go out and try it. You will see everything I've stated is true.

For those who are visual learners, this should help. AutoCAD screenshot follows:
https://www.greenhybrid.com/share/fi.../8/5/tires.jpg

Re: Speed Volume option on radio
 

That guess would be correct. I installed an aftermarket double DIN in-dash NAV setup in my 05 FEH:

http://www.pbase.com/jmorton10/image/66287539


That setup needed a connection to the gray/black VSS wire to do turn by turn routing directions(the NAV maps worked without the wire connected, but the turn by turn voice didn't work)

The truck had not come with the factory NAV & the VSS wire did not extend all the way to the factory radio. I picked up a connection to that wire at the ABS brake module. It was slightly confusing as there was more than one black/gray wire at that plug, but after I figured out which was the correct one it worked fine.

~John

Re: Speed Volume option on radio
 

I haven't read this whole thread, but I can state that my wife used to have a Monte Carlo SS that had one of the early versions of a "low tire pressure" warning system.

I couldn't figure out how it worked at first(& it did work rather well), then I read the owners manual(that's always the last resort for a guy.......)

At least on that particular car, it was simply measuring how fast each tire was spinning. As a tire lost air, it spun faster because it wasn't as big around & a wheel sensor at each wheel would catch & report on the discrepancy.

~John

Re: Speed Volume option on radio
 

I know when my tire was at 29psi the TPM warned me.

Re: Speed Volume option on radio
 

OK, Apples to Apples.....a tire is not a tank tread. There is an "effective radius" and you measure it from the center of the wheel to the pavement, and THAT changes as you let air out of the tire.

You're making the assumption that if the wheel is moving at a constant speed, the outer edge of the tire is too, but look at your diagram and pick a "spot" on the tread and measure the speed as the tire rotates......it's not linear. As the spot passes between the rim and the pavement on a low tire, the speed will increase because the distance the spot on the outer edge of the tire travels is much greater for x degrees of wheel rotation than it is on the "high" side.

It's not a tank tread, and it's not round, and the wheel can move at a constant rate, but the rubber is not.

Re: Speed Volume option on radio
 

This is the fallacy in your thinking. There is no radius at the point the tire hits the road, because the tire is not circular then. This concept is not that hard!!!

If a train's locomotive is going 60 MPH then the caboose must also be going 60 MPH no matter how many curves there are in the track. And no matter how many curves there are in the track, the total length of the train does not change. A flat(er) tire just adds curves to the path of the rubber tire.

The tread on a rubber tire is very analogous to a tank tread.
I don't really care if you believe it or not, it won't change the facts!

"When the comparison of wheel RPM with this ABS wheel speed sensor is performed, because the deviation value is not stable, the tire abnormal air pressure cannot be judged. In short, due to noise, caused by variations in road conditions and vehicle running conditions, etc., as the prime factor, it becomes impossible to perform an accurate comparison.

With the manufacturing error of each vehicle tire as large as 0.3%, and the tire radius change (while moving) due to tire air pressure loss often less than 0.3%, a rather high degree of accuracy is needed for the tire air pressure judgment.

And, as for the aforementioned tire air pressure judgment, when the vehicle is on a low friction road surface or climbing up a hill, rounding a curve, etc., the amount of slip of the wheels gets larger, or the intermittent existence of gravel, snow covered roads, as well as other factors, can lead to the amount of drive wheel slip growing larger. Furthermore, when the slip of the drive wheels is large, the accuracy of the detected wheel velocity signal grows worse. Unless a truly valid signal is utilized for the detected wheel velocity, and the wheel velocity is determined with a high degree of accuracy, it will be difficult to improve the accuracy and dependability of the tire air pressure judgment.

Also, the tire air pressure judgment cannot be carried out when the car is accelerating or decelerating, and nothing is proposed regarding techniques to increase the accuracy or the reliability of the tire air pressure judgment taking into consideration the road conditions or the vehicle conditions.

According to the road conditions (road surface, bad roads, hills, canting road surfaces, etc.), the amount of drive wheel slip increases, the load on the 4 wheels becomes uneven, the wheel velocity of the 4 wheels also becomes uneven, and therefore the accuracy of the detected wheel velocity decreases.

Generally speaking, at low velocities, because the number of data detected from the wheel velocity sensor decreases, the accuracy of the detected wheel velocity decreases, furthermore, at high velocities, because the amount of slip of the drive wheels becomes larger, and because the accuracy of the detected wheel velocity decreases due to the load between the front wheels and the rear wheels fluctuating, the accuracy and reliability of the tire air pressure judgment decreases.

Particularly, as the drive wheel slip amount increases with the road surface friction coefficient, .mu., decreasing, the accuracy of the detected wheel velocity decreases, and the accuracy and reliability of the tire air pressure judgment decreases. When running on bad road surfaces, because the scattering of the wheel velocity of the free and the drive wheels grows larger, and the accuracy of the detected wheel velocity decreases, and the accuracy and reliability of the tire air pressure judgment decreases.

When climbing up a hill, the slip amount of the drive wheels increases, and, similarly to the condition when accelerating, the accuracy of the detected wheel velocity decreases, and the accuracy and reliability of the tire air pressure judgment decreases.

When the normal vehicle tire air pressure is 2 Kg/cm2, and when the air pressure falls to 1 Kg/cm2, the change in tire radius is approximately 0.3%. Because the tire manufacturing defect is also approximately 0.3%, in order to determine a decrease in tire air pressure using the 4-wheel wheel velocity technique, it is extremely difficult to discriminate between the tire manufacturing error and a decrease in the tire pressure.

Therefore a further goal of Mazda is to increase the accuracy and reliability of the tire air pressure judgment, by alternate means of measurement, such as a deviation in axle centerline height from the road surface."

-Source Mazda Motors ( Japan ) c2000

Re: Speed Volume option on radio
 

However, the tighter the curve, the closer the locomotive becomes to the caboose. With that, the effective length of the train gets smaller as the straight line distance between the locomotive and caboose lessens.

While the steel belt and rubber of a tire really doesn't change much, if any, due to air pressure, the effective circumference can change. When the effective circumference changes, the distance traveled per revolution changes.

Take it to an extreme, what happens with the lose of air pressure is that the tread of the tire starts to fold in on itself. With that, the road surface can "jump" over the fold and that "jumping" is what causes the effective circumference to change (reduce).

Re: Speed Volume option on radio
 

Re: Speed Volume option on radio
 

I am glad that we can agree that your train analogy has nothing to do with what we are writing about. I got your point, but that point was irrelevant.

You either misunderstood, or are misapplying, what Mazda said. What you quote from Mazda is for a tire in "free space", not in contact with anything, not supporting a load, nor in motion.

Re: Speed Volume option on radio
 

Hey John,

I am not trying to argue(I am just curious), & although I made a good living as an auto mechanic for years in the old days I have never claimed to be an engineer.

As I stated before, my wife had a 2000 Monte Carlo SS that had low tire warning system(& it did work rather well). It had no sensor of any kind on the wheels or inside the tires etc & according to the owners manual it was relying on tire speed to sense a low pressure condition.

If the tires do not change in outside diameter, how was the system telling when they where low on air???

~John