Run flat alert after tyre change and jet clean

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Doddy

New Member
Joined
Jul 19, 2015
Messages
4
Car
Mercedes a class
Hi folks I wonder if one of the members are able to help please. I've got a 2009 a class classic and I am displaying a runflat tire indicator despite repeatedly resetting .my tires have all checked okay but I have recently had one new tyre on the nearside with a half worn one on the other side I am aware that it uses the ABS and the tire circumference to determine whether you have a flat tyre ,I am wondering if this is what is constantly setting it off I have also just jetwashed all the inside of my wheel wells and I wondering if the water has affected the sensors ?.
my question is ,where are these particular sensors that determine if you have a flat tire and is it possible to clean or check for a loose wire if it has been struck by high-pressure water for instance .I hope you are able to help thanks very much
 
Run flat

It's just the problem didn't start until 2 days after new tyre fitted , but within a few hours of a jetwash , hence wondering if dirt or water on sensor ( wherever it is !)
To be honest it COULD be the rears causing the issues .
Feel like pulling a fuse if they're is one !
I'll try a second new matching tyre and see if it solves . Thanks for reply
 
wondering if dirt or water on sensor ( wherever it is !)

The only sensor is the ABS one. To be precise, it's the rotational speed sensor which feeds the ABS, ESP, etc, systems as well as the tyre pressure loss system. If it was faulty the dash would be lit up like a xmas tree with all sorts of warnings.

As other post, it's probably your tyres, assuming you've actually checked all the pressures are correct.
_
 
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I had a similar problem, when I bought my A200 C169 three months ago. Turns out the NSF tyre wasn't sealed correctly. Once cleaned and refitted - no more warnings.

Incidentally, I replaced the OSR tyre on Olly's advice (plenty of thread, but badly cracked rubber), and that didn't triggered any pressure warnings (after reset, naturally), although to be fair, the NSR is in perfect nick.
 
Run flat

I've checked all pressures and no issues so reckon these sensors may need unplugging and integrity checked ( WD40 if water )the front , I'm guessing ,are more prone from jetting .if not that , then new tyre on the front to match the other . More expense . Appreciate your feedback fellas I'll have a rummage behind the wheels !
Just to clarify please ... On this type and year .... They're is no sensor actually inside the tyre ie: behind the valve is there ?
 
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They're is no sensor actually inside the tyre ie: behind the valve is there ?

Not unless you have the full tyre pressure monitoring system which gives a dashboard display of the pressure in each individual tyre.

But... as per my previous post unless you are getting other warnings about ABS, etc, then it's almost certainly not the sensor.

A half worn tyre on the same axle as a new tyre will cause a different rotational speed that might be enough to rigger a warning. Are you resetting the system rather than just clearing the warning message? Are all four tyres exactly the same size?
 
Runflat

Yes all the same size and all three very good tread with the near side front a brand new .
I actually reset via the dash each time but it keeps coming back albeit not straight away .
Reckon another new front offside perhaps .
Appreciate all the feedback cheers
 

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