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Discussion Starter · #1 ·
On day 5 of our new '08 combi, the dash tells me the front right tire pressue is low, and needs to be checked. The warning goes away that same day. The warning came back on again today, so I got one of those digital tire gagues on it. The "low" tire read 33.5, compared to 32.5 on the other front tire.

The dealer is a good 45 miles away, scheduled to look at it Friday. On the phone, they said it could be the cold weather, but that doesn't seem like it would only sense my front right tire both times.

Faulty sensor perhaps? Or is this a known issue?

Thanks
 

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squiredogs said:
On day 5 of our new '08 combi, the dash tells me the front right tire pressue is low, and needs to be checked. The warning goes away that same day. The warning came back on again today, so I got one of those digital tire gagues on it. The "low" tire read 33.5, compared to 32.5 on the other front tire.

The dealer is a good 45 miles away, scheduled to look at it Friday. On the phone, they said it could be the cold weather, but that doesn't seem like it would only sense my front right tire both times.

Faulty sensor perhaps? Or is this a known issue?

Thanks
Interesting. The first 2003-04's had a tire pressure system, and it was dropped b/c of chronic problems. Hopefully this isn't a resurrection of the same issues with the 2008's!! :evil:
 

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Nickshu said:
Interesting. The first 2003's had a tire pressure system, and it was dropped b/c of chronic problems. Hopefully this isn't a resurrection of the same issues with the 2008's!! :evil:
Well the government made TPWS manatory for 2008. The number of hire cars I have driven with the light on. Gotta make you wonder.
I would imagine it is the cold weather. Cold air is more dense (so would be at a lower pressure in the tire), as you drive the tire will warm, the air expand and the warning light go off.
What pressure does the warning light trigger at?
 

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We have an '04 Aero with tire pressure monitoring. We have had this message several times.

According to the dealer the system does not measure air pressure in each tire.

The dealer said that the system on our Aero compares the circumfrence between the 4 tires; when the system senses enough difference in the circmfrence of one tire or more it gives a warning. In theory if all 4 tires loose air at the same rate the TPM will not sense a difference and will not give a warning.

Because of this it is still important to check tire pressure manually. Do not assume that your air pressure is correct just because the system has not given you a warning.

Later models may have a different TPM system.
 

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Discussion Starter · #5 ·
SMHarman - The system doesn't give a a number, just says that it's "low," and tells me to check.

DPScott - when I put the Radio Shack tire gauge on the tire in question, it was reading like 1 PSI higher than the others - maybe that's why I'm getting a warning.

It's been in the low 30's around here. I guess I'll keep the appointment and make a road trip out of it. Love driving the car anyway...

Thanks guys
 

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DPSCOTT said:
We have an '04 Aero with tire pressure monitoring. We have had this message several times.

According to the dealer the system does not measure air pressure in each tire.

The dealer said that the system on our Aero compares the circumfrence between the 4 tires;
Seems odd that the 04 Aero would work this way. My brothers 04 BMW M3 works that way, but my 04 Arc definitly has the sensors, and they are described on page 229 of the owners manual. Are you sure your dealer knows what he's talking about?
 

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squiredogs said:
SMHarman - The system doesn't give a a number, just says that it's "low," and tells me to check.
Yeh but no but... I don't know how the new system works, as pointed out the old one used the wheel sensors to measure roatational speed and compare / contrast.
Many newer ones use transponders in the tire valves to measure the pressure and if that goes below a certain pressure the transponder sends such information to the system.

Now, the rotational system should mean that on a cold day when all the tires have more dense air in them they will all rotate at that different speed so no warning.

The transponder one could have a faulty transponder that is measuring a low pressure and sending a warning. In this instance the transponders will have a pressure level set in them such that when the pressure falls below the warning will sound, while the system will not tell you that number on the display, that number exists.
 

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Discussion Starter · #9 ·
Would the dealer be able to diagnose a faulty transponder?

SMHarman said:
The transponder one could have a faulty transponder that is measuring a low pressure and sending a warning. In this instance the transponders will have a pressure level set in them such that when the pressure falls below the warning will sound, while the system will not tell you that number on the display, that number exists.
 

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My manual talks about the warning light- but my car doesn't have them...

Is it something that can easily be added? Is it in the computer already and just needs to be activated and add the sending units?
 

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fishhyren11 said:
My manual talks about the warning light- but my car doesn't have them...
it shows on the SID on the dash, just like the washer fluid or the passenger seatbelt warning, etc. Mine went off once right after I added pressure to my tires, but not again after I cleared it.
 
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