I have a ford s max 2009 2.2 diesel car.

In the settings menu all 4 tyre pressures are reading correctly but I am still getting a message that says the tyre pressure monitoring system is faulty.

I would be grateful if anyone who has had a similar problem could offer some advice.

Many thanks

Each wheel contains a sensor, and each sensor contains a battery. Batteries only last so long. Most likely problem is that the batteries are going flat, and no they can't necessarily just be replaced, in some/all cases you need to replace the entire sensor, or else you have a difficult job hacking them up to forcibly replace the battery, and either way you need to take the tyre partly off each wheel to get at the sensor. It's won't be a cheap job. Note that TPMS failure will fail an MOT.

To have more certainty what is wrong, you need a scan tool of some kind, possibly one that is capable of reading Ford specific codes. Either you could buy one, or you could just pop into your local garage and ask them to plug theirs in and see if it can get the codes. They may even be kind enough to do this simple diagnostic task for free.

Thanks for the reply rd457

I would have thought that as all 4 sensors are communicating the correct pressure to the control module (wherever that may be) the batteries in the sensors are ok.

Its what happens to the info after that module that seems to be faulty.

I have forscan software so i will have another look to see what is happening. 

If anyone knows where the tpms control module   is that would be really helpful

The tpms is controlled by the cjb, central junction box. There are antennas at each wheel arch that pick up the signal from the sensor in each wheel. That about it. 

is there a reference pressure ?

on my non Ford car with real individual TPMS sensor showing each wheel's pressure - you can reset the threshold of what you want normal to be - so it throws its teddies when x wotsits away from this - its sometimes adjustable to accommodate the use of different types of wheel and tyres for summer winter change.

I'd set the pressures to std and then hunt the owners manual for a reset procedure...

 

Yeah, fords the same. Pump the tyres to the correct pressure then reset the tpms that then recognises each tyres pressure .

But if the system is saying faulty, I'm guessing either an antenna or sensor is intermittently having a wobbler even though the pressure may being picked up sufficiently to show . 

 

I'd missed the fault message

a few years back I got 4 after market sensors and the coding pad for £100 - never see the deal these days on ebay - they were autel ones - you code the car spec to make them work like that manu, then code the info the current ones have and the car doesn't get muddled or argue - works a treat if using other sets of wheels back and forth (or need 4 batteries)

they recently moved the firmware on the pad so it can code BMW bike sensors too