Tire pressure monitoring system malfunction / false alarm
#1
Tire pressure monitoring system malfunction / false alarm
It's a totally worthless piece of technology they crammed into the car. I'm convinced it's just there for the salesman at the dealership to yap about to people who don't know any better and/or are too stupid to tell when there's a significant loss of pressure in one of the tires when driving. So anyway, here's what happened. I'm driving down south to Laguna Beach on the 405 going about 90mph and about 6 miles from my exit the light starts blinking, I didn't feel that a tire was going down so I just continued on and ignored it until I got to my destination at which time I checked the pressures with the gauge I carry and they all came out within 2 psi of each other. I decided to wait a couple hours to check it again when they were cold and again, within 2 psi of each other. So, I just reset the light and didn't think anything of it. Then a few days ago it goes off again, this time I'm going around 40mph and once again there was no pulling or drifting sensation so I continued on 'til I got home and did the routine again and once again everything was fine and I reset the system. My 1st service is coming up on the 13th and I'll have them check it then, but if they don't find anything and it goes off again I'm gonna have to figure out how to disable the system. So, anybody have a similar experience and if so, what was the solution? And if you ended up disabling the system, what is involved in doing this? Just pull a fuse?
#2
#3
It's funny that this thread started today, because the exact thing happened to me 2 days ago. 75 mph on the interstate between Tampa and Orlando and "DING". I was looking around like a moron for what went "DING" until I noticed the flashing yellow indicator. Pulled over, checked my tires, and nothing wrong.
Maybe all the flat tire indicators are plotting something. No idea how they are talking to one another.
Maybe all the flat tire indicators are plotting something. No idea how they are talking to one another.
#4
Had you been driving spiritedly before the light went off? I throwing the car around turns one day and about 30 minutes later the light went off. If the car detects multiple changes in rotation from the same tire, I assume it throws the light. Therefore, alot of barking tires could lead to a light.
#5
I had my first false alarm on Sat. 07/03. I was out playing in the twisties but had pulled off on to a side road I wanted to check out. Pulled a 'u'ie and went onto the dirt a bit and a few seconds later...ding ding! Didn't feel any thing different (first time this happened I had a screw). Got out and checked my tires...nothing except a small rock stuck in the tread. I made it to a gas station and checked them...seemed fine. Drove around for a bit and it never came on again. The next day I went back out and did some rippin' around and still nothing.
I'm guessing it was the Black Star Canyon demons that set it off....too early for Halloween stories?
-Cyn
I'm guessing it was the Black Star Canyon demons that set it off....too early for Halloween stories?
-Cyn
#6
I had the light go off 2 weeks ago after rotating the tires and it also seemed like a mystery. Called the service advisor and he told me that having the tires rotated most likely set it off. It is sensitive enough to note that there was a 2 pound difference between the front and rear tires. Reset the light and no problems since.
#7
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#9
Originally Posted by iamwiz82
Had you been driving spiritedly before the light went off? I throwing the car around turns one day and about 30 minutes later the light went off. If the car detects multiple changes in rotation from the same tire, I assume it throws the light. Therefore, alot of barking tires could lead to a light.
#10
Mine went off today and I was indeed driving "spiritedly." I found one tire to be 4 pounds lower than the other three. Also I put tires on that have an overall diameter about 2% less than factory tires.
I do believe that this system, on this car is more than just something for the salesman to talk about. The S version has no spare. Their thinking was good, maybe the execution of the idea came up a little short.
I do believe that this system, on this car is more than just something for the salesman to talk about. The S version has no spare. Their thinking was good, maybe the execution of the idea came up a little short.
#11
#12
Originally Posted by akajoker
I had the light go off 2 weeks ago after rotating the tires and it also seemed like a mystery. Called the service advisor and he told me that having the tires rotated most likely set it off. It is sensitive enough to note that there was a 2 pound difference between the front and rear tires. Reset the light and no problems since.
weird
#13
Just to add to this post, I rotated my tires today---2nd time in 6,000 miles. The flat tire sensor went off when I first installed the tires, not at the first rotation, and again tonight--just after the tire rotation. I'd driven about 30 miles or so after the rotation when the light went on and I heard a ding.
#14
mine went off last week after I washed my car.Wonder if the water has anything to do with this?Checked the pressure,attempted to re set( position 2 on ignition ,push button in front of E brake),and the damn thing would not shut off.tried several more times and noticed several days later that it had finally gone to sleep.The only other time it happened to me was right after being serviced and coming off a lift.went off some time later after starting and stopping the car several times.Just once I'd like this thing to work as designed, not that I want a flat tire or any thing , but ,you know , the wolf wolf thing....
#16
#17
Just to clarify...the tire warning does not sense the air pressure...it works by monitoring the relative rotational speed of each wheel via the ABS sensors in each hub. If one wheel is consistently rotating faster, it assumes the tire is lower in pressure and thus the tire diameter is slightly smaller...giving a (slightly) higher speed of rotation. Knowing this could help you figure out the problem...is there excessive wear on one or more tires? Is there something stuck in the tread of one tire? Is the ABS sensor or hub ABS grated ring clean (these can accumulate brake dust which can affect the how the system works)?
Mike.
Mike.
#18
Just for fun, here is a graph of the individual wheel speeds while doing an "S" turn:
You can see that they vary quite a bit, and every bump in the road shown up as a blip first in the front wheelspeed, then in the rear wheelspeed, so the flat-tire monitor needs to be fairly smart about it.
Can you tell which tires (front or rear) I keep more air in from this graph?
I built a gizmo to read the CAN bus that comes up to the tachometer and captured this information.
You can see that they vary quite a bit, and every bump in the road shown up as a blip first in the front wheelspeed, then in the rear wheelspeed, so the flat-tire monitor needs to be fairly smart about it.
Can you tell which tires (front or rear) I keep more air in from this graph?
I built a gizmo to read the CAN bus that comes up to the tachometer and captured this information.
#19
It's interesting that the left or right side wheels track very close to each other in this graph. Would be a neat test to let some air out of one tire and repeat the tracing....
Mike.
Mike.
Originally Posted by Trippy
Just for fun, here is a graph of the individual wheel speeds while doing an "S" turn:
You can see that they vary quite a bit, and every bump in the road shown up as a blip first in the front wheelspeed, then in the rear wheelspeed, so the flat-tire monitor needs to be fairly smart about it.
Can you tell which tires (front or rear) I keep more air in from this graph?
I built a gizmo to read the CAN bus that comes up to the tachometer and captured this information.
You can see that they vary quite a bit, and every bump in the road shown up as a blip first in the front wheelspeed, then in the rear wheelspeed, so the flat-tire monitor needs to be fairly smart about it.
Can you tell which tires (front or rear) I keep more air in from this graph?
I built a gizmo to read the CAN bus that comes up to the tachometer and captured this information.
#20
run flat light
I have a set of the stock run flat tires, and a set of Kumho's on stock rims. I swap between these regularly.
The first three swaps, the flat tire indicator would go on more than ten but less than 20 miles after a change of tires.
I also had it go one once after a track day, when I reset the pressures to "street" and left the track. The light went on in about 5 miles. I later discoverd when the tires cooled, that the pressures were about 5 pounds from where they should be. I attributed this to the tires cooling off in normal driving.
I read some where that the alert is triggered by the difference between front and rear tires.
I don't know if the system has increased its tolerance, or I am paying more attention to make sure that the front / rear pressures are the same in both sets of tires, but the last 3 or 4 tire changes I have not gotten the light.
The first three swaps, the flat tire indicator would go on more than ten but less than 20 miles after a change of tires.
I also had it go one once after a track day, when I reset the pressures to "street" and left the track. The light went on in about 5 miles. I later discoverd when the tires cooled, that the pressures were about 5 pounds from where they should be. I attributed this to the tires cooling off in normal driving.
I read some where that the alert is triggered by the difference between front and rear tires.
I don't know if the system has increased its tolerance, or I am paying more attention to make sure that the front / rear pressures are the same in both sets of tires, but the last 3 or 4 tire changes I have not gotten the light.
#21
Mine used to go off fairly regularly - at least once a month, sometimes a few times a week. The system doesn't offer much security if you eventually come to ignore it, assuming its just another false alarm. IF the system worked correctly I think it would be great... alas, in 1 1/2 years of ownership, mine never did.
#22
#23
#24
Tornado is quite right in that the sensors detect rotational speed, not pressure; the theory being that once the tire loses pressure, it rotates ata different rate than the other tires.
I have also had some false alarms but wouldn't recommend disabling the system as the run flats really don't give a very good visual indication if they are low. In fact, last month, the warning light went on and I discovered a CHUNK of metal (1 1/2" x 2") completely imbedded in my left rear tire so it does have a useful function. Drove around on that for a few days, albeit at a less spirited pace, until the new tire came in without problems. Says a lot for those Dunlop Runflats.
I have also had some false alarms but wouldn't recommend disabling the system as the run flats really don't give a very good visual indication if they are low. In fact, last month, the warning light went on and I discovered a CHUNK of metal (1 1/2" x 2") completely imbedded in my left rear tire so it does have a useful function. Drove around on that for a few days, albeit at a less spirited pace, until the new tire came in without problems. Says a lot for those Dunlop Runflats.
#25
2nd Gear
Join Date: Jul 2004
Location: Vancouver, WA USA
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My warning light went on yesterday and I checked the pressure. They were all down, probably due to the colder temps. I inflated them to 38psi as called for, but the light won't go out - it burns steady. I pushed the button and drove a bit, but the light is still on. Any suggestions?
Thanks,
John
Thanks,
John