As I await our new Orange Revolution Sport w/Nav, rolling off some production line in Japan, I have been looking and pondering. I found a copy of the owner's manual (from another fitfreak thread), and that generated a question.
Our 2008 BMW 335i has a Tire Pressure Monitoring System. After you get the tires set up at desired pressure, you go through a calibrate procedure via the iDrive controller. After a short while, the system apparently memorizes all 4 tire pressures, and detects if there is a subsequent substantial loss of pressure at any wheel - about 4 psi is considered the trigger. If detected, you get a warning, and can pull up a diagram which shows the location of the offending tire. In the one event I experienced, the left front was at about 27.5 psi, which generated the alarm, while the right front was at about 28.5 psi, and was not alarming the system. The cause was a sudden overnight drop in temperature.
I assume the Honda Fit's TPMS is similar. However, the owner's manual does not mention the need to recalibrate after adjustment of tire pressures. Is it possible this function is automatic on the Fit, while it is a royal pain in the butt on our waaaaay more expensive Bimmer?

 

Welcome to the wonderful world of honda! Im pretty sure you dont need to calibrate anything. Its automatic as far as I know. If one of the tires is low, the TPMS light comes on. I dont think it lets you know which one it is or what the psi is but still informs you that a tire is low. Can anyone else second that???

 

AFAIK, we'd have to go out and check each tire individually.

 

mine came on a few times and then never came on again... even with new wheels.

 

Honda's TPMS is fixed setting at 24 to 26 psi. the signal generates any time even one tire pressure falls below 26 to 24 psi. However, there are a lot of owners complaining about the TPMS alarming at even higher pressures. It is after all a 'cheap' government mandated system, except to owners. Honda sensors cost about $60 each. How much is the sensors in the 335?. As a guess I'd say $185 - each.

 

.......

I hope never to find out the price; everything BMW is ripoffrageously expensive. You truly need TPMS with their run-flats, since a tire with 0 psi looks essentially the same to the inspecting eye as one with 35 psi. And the 255/35 x 18 V rated rear tires are definitely over $300 apiece. Not that the 225/40 x 18 fronts are much cheaper.

I certainly can understand that if the Honda TPMS is tied to a fixed pressure value, and not a difference relative to the one to which the owner has inflated the tire, the need for calibration goes away. BMW complicates the situation by recommending one set of pressures for high speed driving, and a somewhat lower set for more 'normal' driving.

 

$126.55, complete, for four TPMS sensors at: https://www.hondapartsdeals.com/login.php !

I thought it was a good price!

 

BMW typically uses the ABS wheel speed sensors to determine if tire pressures are ok. If a tire is low the diameter of the tire changes which causes a different # of revolutions than the other tires.

Honda on the other hand uses actual pressure sensors in each valve stem to monitor pressures. The lower models, including Fit, do not tell you which tire is low by the light on the dash, the light comes on if any are low. You can use the HDS scan tool to determine which tire set the low pressure code but sometimes is ti more complicated to use the scan tool and Bartec tools to determine which tire vs just checking all tire pressures and determining that way. Some of the higher models (ie Acura, Odyssey, etc.) will actually display which tire is low on the dash, it comes down to the difference between a $19000 vehcile and a $40k + vehicle.

 

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May I please correct the info. For model years 2007 and earlier, BMW used a system they called FTM (Flat Tire Monitor). FTM did indeed use the ABS sensors to recognize changes in relative rotational speed for tires on the same axle, and thus detected severe underinflation. FTM had to be recalibrated after each time you readjusted the tire pressures.

For 2008 - 2009, BMW went to the TPMS, which used individual wheel sensors. I have this on the 335i. It also requires a recalibration after pressure adjustments. It detects loss in pressure relative to value at time of calibration, and responds to a difference as small as roughly 4 psi. For your $45,000 - $50,000, you do get a nice little diagram on the iDrive controller which shows you the offending low tire.

 

I don't have a frikkin' clue how it works, but on the C-RV, and Pilot, it lets you know which individual tire is low. Not so much on the Fit

 

I really don't understand why people want complex systems like these. A good tire pressure gauge can be had for $10 and it takes a few minutes to check your tires. I'm very glad that my Fit doesn't have any of this stuff.

 

Thanks for the clarification, I haven't has to work on any of the new ones yet so I assumed they were still the same, good info incase I need to work on one soon!

 

Again Pilot and CRV are more expensive vehicles and do indeed let you know what tire is low....wish they all did that but they don't. Basically the way it can tell is that there is a reciever near each wheel well that registers what the sensor inside the tire is reading, from there it tells the conrtol unit if tires are good or bad, the control unit then turns the lights on the dash, the control unit on some is set to turn on only 1 light if any tire is low and on others it will turn on a light for any or all tires corresponding, others like the Odyssey can even show what the actual tire pressure is on the dash.

 

CRXsi#32: I notice you are Canadian. I think this entire thread applies to both Canadian and US versions of the Fit. The S2000 is pretty much the same both sides of the Border; not so sure about BMW models.
If you will pardon my going slightly off topic, how do the Fit model prices in Canada compare to US prices [note: Canadian dollar = .816 USD]?

 

The Canadian Fits don't have TPMS.

 

That's a cool feature the larger Honda vehicles have where you can tell the individual psi of each tire.
You could get one of these Mugen systems


https://www.fitfreak.net/forums/2nd-...ing-gauge.html

but after I heard how much it will cost.. definitely not worth it...
Maybe there's a less expensive alternative with the other Honda options (for the Pilot, Odyssey, etc.)

 

People don't want these; governments do to increase the cost of living.
Worse, it is expected here that those TPMS be part of inspections a la emissions.
Welcome to socialism.