Tyres pressure monitor not working

Jimyu · Post by **Jimyu** » Sat Jun 25, 2016 11:02 pm

Has anyone experienced the sensors not working at all? Or can they be deactivated?

I unknowingly drove on a flat tyre earlier until it split

but no warning lights came on??

I have an e46 m3 and the sensors are ultra sensitive on that and presumably it's exactly the same system?

Beedub · Post by **Beedub** » Sun Jun 26, 2016 10:35 am

Jimyu wrote:Has anyone experienced the sensors not working at all? Or can they be deactivated?

I unknowingly drove on a flat tyre earlier until it split but no warning lights came on??

I have an e46 m3 and the sensors are ultra sensitive on that and presumably it's exactly the same system?

how on gods earth did you not feel it was flat!! the difference and noise is unreal.

Jimyu · Post by **Jimyu** » Sun Jun 26, 2016 10:44 am

No idea but I didn't. Breakdown guy said it was quite normal not to notice on 19's.

Anyway....

exdos · Post by **exdos** » Sun Jun 26, 2016 6:45 pm

Beedub wrote:
how on gods earth did you not feel it was flat!! the difference and noise is unreal.

As you know, I've always said the Z4MC'suspension was too stiff, but I did know it was THAT stiff!

monaco_blue · Post by **monaco_blue** » Sun Jun 26, 2016 9:35 pm

Different cars have different systems. No idea where you're located as the system varies with the market. In the UK the ABS sensors are used, at least on early cars, to detect rotational speed differences between wheels; there are no sensors in the wheels themselves. Having had a few false alarms indicating low pressure I can imagine the opposite could occur - no alarm at all. The system that has a sensor within each wheel is generally more accurate as it measures actual pressure but it's also more costly.

VRSteve · Post by **VRSteve** » Sun Jun 26, 2016 10:08 pm

If your running 19s then you must be on really low profile tyres???

I guess the rolling radius between the flat and not flat just isn't enough to trigger a warning.....get smaller wheels!

Jimyu · Post by **Jimyu** » Sun Jun 26, 2016 11:17 pm

VRSteve wrote:If your running 19s then you must be on really low profile tyres???

I guess the rolling radius between the flat and not flat just isn't enough to trigger a warning.....get smaller wheels!

Yes running csl 's on 265/30/19 but I can't believe the sensors can't notice a fully deflated/blown tyre. They do on my m3 with 19's and I believe it is the same system (2005 m3, 2007 z4mc)

I will get it checked out as it will be my wife's daily. Day one of ownership and 6 hour tow home - it's the best mpg it will ever do

Herminator · Post by **Herminator** » Mon Jun 27, 2016 12:29 pm

They are sensitive enough to notice the difference.
I'm running 19's and the sensor went off a few times when I had a puncture and well before the tyre actually looked deflated.
They don't compare wheels though, as one tyre might be new and have more tread than the other. They go by change in reading over a short period of time. So a very slow puncture can go unnoticed.
Get your tyres changed and you'll probably have to reset the system as it thinks the tyres have suddenly gotten larger.

D4dawg · Post by **D4dawg** » Mon Jun 27, 2016 12:39 pm

VRSteve · Post by **VRSteve** » Tue Jun 28, 2016 10:21 am

D4dawg wrote:Ouch ,
On my 224s it picked up a screw in tread
And on 19s a tyre that hadn't been filled to correct pressure so do seem to work buddy

On our cars in uk it's the sensor that's located on the caliper not an internal wheel one as other countries have it appears
Take wheel off give it a darned good clean and check
Then with wheel back on
Reset it by holding button till light out
Drive at normal pressure then I'd test it by lowering pressure and see if it picks up as on 19s we don't have much room to deflate with 30 profile

Give what a clean?? The ABS sensor???

Why bother???

If the ABS sensor was broken the OP would know about it by now.

If it ain't broke, (especially with sensors) leave it well alone!!

monaco_blue · Post by **monaco_blue** » Tue Jun 28, 2016 2:53 pm

The ABS sensor isn't on the caliper; it's on the wheel hub. And by and large either they work fine or they trigger a DSC/ABS warning light on the dash.

There's a pad wear sensor on the caliper - might you have mixed the two up?

Jimyu · Post by **Jimyu** » Fri Jul 01, 2016 12:14 am

Herminator wrote:Get your tyres changed and you'll probably have to reset the system as it thinks the tyres have suddenly gotten larger.

So I reset the system with the blown tyre before fitting the new tyre and it didn't pick it up. I will try resetting the system then letting 10psi out and see what happens.

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