BMW E90 TPMS won't reset

[Mr Tidy]

I took my 3 Series away for a few days and 100 or so miles into a 500 mile round trip the TPMS red light came on.

I checked the tyre pressure and they were all OK so I tried to Initialise the TPMS but the red light came back on. Tried several more times with the same result.

I've booked the car in to RBM buy Ross said it would be handy to see what fault code there was so I plugged my C110 scanner in but when I tried to check TPMS it had a communication error.

Being a 2005 car it doesn't have pressure valves on the wheels but uses the ABS sensors like E85/86s. I'm guessing it's a wheel speed sensor problem but any advice would be appreciated.

[Pondrew]

Iain,
Just a thought but try turning on the engine, with the steering at centre, then turn it lock to lock a couple of times while stationary. Then turn ignition off for a couple of minutes. Turn it back on and see if either the fault has gone, or it will reset the tpms.

The wheel sensors can sometimes 'forget' their setting, so the above recalibrates them. It's normally associated with low battery voltage but is worth a try.

Best of luck buddy

[enuff_zed]

Did you hit a large pothole, or maybe drive through a large or muddy puddle?
It does sound as though it is an ABS/wheel speed sensor, though of course on the Z4 it would be accompanied by an ABS light at the very least.
The sensors are quite fragile it seems: hammering a stuck disc off with a rubber mallet caused enough transmitted shock to kill my front left one.
But it could simply be a lump of grit, or something metallic wedged between the sensor and the reluctor ring?
If your pressures were all good then there's not much else it could be really.

[Mr Tidy]

Thanks guys.

The battery may be getting tired so I'll check that first as getting from lock to lock without the engine running may be hard work seeing as it has HPAS (thankfully)!

I didn't hit any big potholes so maybe I need to whip off a wheel or two and take a look.

[Mr Tidy]

Well I couldn't see anything obviously wrong. Tried to scan codes several times with a C110 scanner but each time I tried TPMS all I got was a communication error.

Then when I took it out on Friday I noticed the Climate Control came on at some random settings, so I thought maybe battery?

But I couldn't find my multi-meter anywhere - probably because most of the shed has been boxed up for months pending a never-ending house move!

I had it booked in with Ross today and sure enough climate settings were random again, and OBC was showing average mpg although I always leave it on range.

Sure enough Ross found loads of low voltage fault codes so the 7 year old battery got replaced - all good so far.

So yet another false alarm on a BMW with a failing battery.