Tpms fault

[TallPaul73]

Morning all.
I keep getting Tyre Under Inflation Monitoring fault sporadically. Tyres are fine and it shows for all wheels? Im presuming its a comms fault. Sometimes it lastf for a few minutes sometimes a day or 2 but always resets itself.
Any ideas??

[RichardW]

These use the wheel speeds rather than an actual sensor, and if the programming is the same as our Picasso, it comes on with what looks like a fault when it's actually a low pressure. However if you've got a wheel speed sensor that's gone a bit wonky, or even a mis matched tyre that might set it off. Have you re-initialised the system? If not, then diag required to see what's setting it off.

No, I was wrong!

[Paul-R]

What vehicle and what year? Without this information no valid answer can be given.

[GiveMeABreak]

The DS5s had direct TPMS fitted, so is likely to have more potential causes, like a problem with the TPMS module itself if all 4 tyres are not monitored. Has anyone been doing anything diagnostic wise to partially disable the system?

Has this just happened?
Has it been working fine before?

I doubt it is the wheel sensors for this year (2017) as a) the batteries should last for at least 10 years, and b) they would unlikely all go at the same time, so there is something else going on. Best to pop your VIN up so we can confirm system used, but for a sporadic issue, it may be the module or the electrical plug or connection to the TPMS module.

Also on the earlier version and there's no indication this has changed, the high frequency receiving aerial on these is integrated into the wiring harness, so it's a possibility that there may be a break somewhere there...

[TallPaul73]

Hi Marc
My vin is VF7**************[VIN obfuscated, can be read by forum staff]
Its only happened a coupke of times. Theres been nothing done on the car recently.
The fault has now gone again.
Its just bugging me why its happened. Tyre pressures are all ok and the fact it shows all 4 wheels led me to believe a possible comms issue.

[GiveMeABreak]

So confirmed that you have the 'Direct' TPMS, system, so a transmitter valve in each wheel and a receiver unit.

You didn't mention what the actual message was, which would help, but if it does not relate to a specific tyre puncture or flat tyre warning - and shows all 4 tyres on the display, then it's likely to be a CAN data network issue at the receiver / or the module itself, especially if intermittent.

[TallPaul73]

Hi Marc.
The message is Under inflation monitoring fault
It shows all 4 tyres on the display and can show for anything from a few mins to a few days and when it clears it may stay clear for a couple months then reappear again. Or it may reappear the next day. Very sporadic

[GiveMeABreak]

Ok, so that would confirm a problem with the communication to / from the TPMS ECU / receiver or the unit itself and rules out the sensors.

I also have to assume you haven't had anyone attempt to disable the TPMS with a diagnostic tool of course.

[TallPaul73]

No one has done anything with tms. This issue first arose for about 3 hrs a few months ago the disappeared and has now started popping up again. It happened yesterday and cleared itself within a few mins then reappeared on my way hone from work last night

[GiveMeABreak]

Ok, so that's fine and just eliminates that as a possibility. So needs some further checks. The ECU is contained somewhere behind the BSI in the passenger compartment glovebox, so will mean disturbing a lot of wires to get to no doubt. They're not too badly priced, circa £198 inc. from the dealer excluding fitting, but really should be double checked in case it's a connection before replacing - especially as it's an intermittent fault, so could be something simple like the wiring block connection.

[TallPaul73]

Thanks Marc. Ill investigate in a few days when i ha e aome time. Thanks for ur help

[NotAnInterestingName]

Are you sure it's showing for all four? I can't remember what mine showed when it got triggered, but I'm wondering if it's just a generic icon representing the system as a whole. Take a picture if possible the next time.

In my case I had a tyre changed. It was blown up to the correct pressure, message wouldn't go away. I (wrongly) wondered if the garage had damaged the sensor.

I fixed mine just by letting almost all of the air out of the tyre, until it was almost collapsing under the weight. Then blew up to the correct pressure, message immediately went away and has been happy for a year since.

It's a bit of a fragile system!