Tyre Pressure Warning + random coincidence has me questioning my sanity

[mattaus]

Hi all,

This arvo I was driving along the highway at 100km/h with cruise control minding my own business in the left lane. I had music playing quite loudly. I turned off the highway and as I made an immediate left turn, I noticed the person behind me flashing their lights. it was a one way road, so the flashing was for me. This prompted me to look at my dash and I noticed the tyre pressure warning light was solid on.

I had noticed no odd feeling through the steering wheel, and even though the music was up I couldn't hear anything odd going on. Thankfully there was a servo right there so I pulled in, check the tyre pressures on all 4 wheels. All were at 39PSI but to be 100% sure I filled them to the specified pressure (280kpa/40PSI). I followed the manual and reset the pressure monitoring system.

I performed a visual inspection of all 4 tyres, as well as the rest of the car. Everything is where it should be and nothing looks 'off'. I drove the rest of the way home with the windows down and music off, listening intently for anything that wasn't right. As far as I can tell there is not a damn thing wrong with my GTI.

Any ideas? If I had received no flash I wouldn't have thought anymore of it, but the fact this lady flashed me is sending me loopy. Did she see something? I can't have cut her off or done anything warrant the flash via my driving. She gave me no gesture as she drove past as I pulled over. I recall her looking at me but nothing to suggest I had pissed her off or that something was wrong with my car.

Is she just messing with me lol!?

Anything in particular people suggest I look at?

Cheers,

- Matt

[cd_r]

I've had people wave me down before to let me know that I had a flat tyre but it was just them confusing the low profile tyres

Hopefully it was just a complete coincidence that the warning light played up at the exact time that someone confused the low profile tyres

I didn't realise the GTI PP came with low pressure warning so I learned something new today

[agentthumb]

I didn't realise the GTI PP came with low pressure warning so I learned something new today

All MK7 have it. It's not the more expensive pressure sensor in wheel type.

Rather, the mk7 uses individual wheel speed sensors to detect when a wheel is spinning at different speed to other wheels due to a flat (change in wheel circumference). It's cheaper but also less sensitive. You also can't get pressure read out on the screen, unlike the more expensive version.


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[Dutch77]

Maybe she was offended by your wheels.

[Guest001]

I would check the inner sidewalls for bulges. Have seen that before when tyres looked fine from the outside

[jjjrules]

Maybe she liked the cut of your jib!

[JustCruisn]

She was letting you know there was a Pokemon in the back of your car
AFAIK all VW use the ABS wheel speed sensors to detect a flat tyre, thing is if all wheels go flat at the same rate the system does not detect it.
A recent pressure check on found all 4 at 28PSI not the 34 set a month or so ago.

[mattaus]

Dutch....

I've checked for bulges. I'm just going to have to wait and see if the sensors go off again. Thankfully I have a service booked for next Friday so I'll mention it then.

For the time being, it appears to have been an coincidence!

[DV52]

Hi all,

This arvo I was driving along the highway at 100km/h with cruise control minding my own business in the left lane. I had music playing quite loudly. I turned off the highway and as I made an immediate left turn, I noticed the person behind me flashing their lights. ............................

- Matt

Matt: hi. I read your storey with interest and I have my own hypothesis which goes like this-

I'm sure that you already know that the tire pressure indicator uses the four wheel speed sensors to compare the rolling circumference of the individual wheels (it actually also compares the vibration characteristics). The process that the mk7 uses is a "poor cousin" of the more sophisticated systems that use actual pressure transmitters in the individual valves and a complex aerial set-up.

In the mk7, the monitoring process is an "approximation" of loss-of-tire-pressure by the ABS control module (because actual pressure transducers aren't used) and it is prone to false -positives. The system can be confused by things like loading on one side of the vehicle, or increased tension on one of the axels.

I wonder if the particular combination of highway speed and (perhaps fast) left-hand turn - particularly if the road surface had loose gravel - simulated a set-of vibrations that set-off the alarm?

Don

[mattaus]

Matt: hi. I read your storey with interest and I have my own hypothesis which goes like this-

I'm sure that you already know that the tire pressure indicator uses the four wheel speed sensors to compare the rolling circumference of the individual wheels (it actually also compares the vibration characteristics). The process that the mk7 uses is a "poor cousin" of the more sophisticated systems that use actual pressure transmitters in the individual valves and a complex aerial set-up.

In the mk7, the monitoring process is an "approximation" of loss-of-tire-pressure by the ABS control module (because actual pressure transducers aren't used) and it is prone to false -positives. The system can be confused by things like loading on one side of the vehicle, or increased tension on one of the axels.

I wonder if the particular combination of highway speed and (perhaps fast) left-hand turn - particularly if the road surface had loose gravel - simulated a set-of vibrations that set-off the alarm?

Don

It's possible, but I drive the exact same route home from work every single day. Of course the conditions change, but nothing stands out to me as being all that different. I certainly didn't corner any faster than normal

Maybe something did fall off my car, which is why the lady flashed me (hehe) and it hit a wheel on the way out causing the sensor to trip?

I'll do another check before I drive to work tomorrow for missing under-car body panels. Also, if the sensors go off not long after leaving home (given the way they work they won't go off the second I start the car) then I'll assume I have a very slow leak somewhere and get it checked out on my way to work.

[AJW]

My tire pressure monitoring went off the other day on my GTIPP as I was about to drive from Sydney to Newcastle for a work.
The day before I'd pumped all the tires to 40psi and the rear inside tyre was reading about 32psi.
Rolled the car backwards looking at the tyre in as many spots on the wheel as I could - didn't see anything.
Thought I had a slow leak, got home after 2 days after looking multiple times at the tyre and found a screw on the inside of the wheel.
So it needed about 8psi difference on one wheel before it would indicate an issue.

[mattaus]

My tire pressure monitoring went off the other day on my GTIPP as I was about to drive from Sydney to Newcastle for a work.
The day before I'd pumped all the tires to 40psi and the rear inside tyre was reading about 32psi.
Rolled the car backwards looking at the tyre in as many spots on the wheel as I could - didn't see anything.
Thought I had a slow leak, got home after 2 days after looking multiple times at the tyre and found a screw on the inside of the wheel.
So it needed about 8psi difference on one wheel before it would indicate an issue.

Interesting, although my pressures were all the same when I checked. If nothing goes off early on my drive to work, I'll stop by a servo and test the pressures again.

[Mattlock]

From my experience, it seems to be only helpful if you have a big loss of air suddenly. I check my pressures every 3-4 weeks and I see movement of 2-4 psi across all 4 and it never goes off.


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[mattaus]

Well everything checked out today. No repeat issue and all parts are definitely still on my car. Case closed due to lack of sufficient evidence.

[turtle]

My GTI PP has done the same thing a couple of time. I wouldn't be too worried about it. The method it uses to calculate low pressure isn't too reliable.