Tyre pressure monitor - showing low but pressures are the same both sides
- Thread starter Motorhead
- Start date
Hi Jeff,
TBH I didn't realise there were separate batteries for the TPMS, I had assumed it would just run off the main car battery - you live and learn! [
]
No idea if they have been replaced, I bought the car last year from Brooklands Service Centre and it had just been serviced then, but I don't know whether they replaced the batteries during that service. It's going back to them at the end of August for an MoT so I'll probably check with them then.
Thanks
Caroline
TBH I didn't realise there were separate batteries for the TPMS, I had assumed it would just run off the main car battery - you live and learn! [
]No idea if they have been replaced, I bought the car last year from Brooklands Service Centre and it had just been serviced then, but I don't know whether they replaced the batteries during that service. It's going back to them at the end of August for an MoT so I'll probably check with them then.
Thanks
Caroline
Try changing to psi. 1.0 bar is 14.5 psi, maybe a rounding difference using bar that might not arise with slightly more granular psi units
HI all,
Just wondering if anyone else has seen this. I got in the car (64 plate 981 Cayman S) this morning and when I started it up the tyre pressure monitor told me two tyres (front off side and rear near side) were a bit down on pressure. So after adding a bit of air I got back in and it was still showing 0.1 bar down on the off side front tyre (rear showed fine). However when I switched to show the actual pressures they were both the same on each side so I decided to drive it anyway. The numbers stayed the same on both front tyres for the entire 25 mile drive but the error would not go away, and even if I dismissed it, it kept popping back up on the console showing -0.1 bar down on the off side front.
Has anyone else seen this sort of behaviour? Is the pressure monitor (either the absolute pressures or the amount it is low) on the Cayman actually reliable or is it just a guide? Will it go away the next time I drive the car (assuming the pressures are actually OK)? I'm just concerned that the management system thinks this is an error but the absolute numbers don't seem to back that up - and also I have seen differences of 0.1 bar from one side to the other when just driving along without it showing as an error, so it seems odd that it is showing this as an error now.
Thanks
Caroline
Just wondering if anyone else has seen this. I got in the car (64 plate 981 Cayman S) this morning and when I started it up the tyre pressure monitor told me two tyres (front off side and rear near side) were a bit down on pressure. So after adding a bit of air I got back in and it was still showing 0.1 bar down on the off side front tyre (rear showed fine). However when I switched to show the actual pressures they were both the same on each side so I decided to drive it anyway. The numbers stayed the same on both front tyres for the entire 25 mile drive but the error would not go away, and even if I dismissed it, it kept popping back up on the console showing -0.1 bar down on the off side front.
Has anyone else seen this sort of behaviour? Is the pressure monitor (either the absolute pressures or the amount it is low) on the Cayman actually reliable or is it just a guide? Will it go away the next time I drive the car (assuming the pressures are actually OK)? I'm just concerned that the management system thinks this is an error but the absolute numbers don't seem to back that up - and also I have seen differences of 0.1 bar from one side to the other when just driving along without it showing as an error, so it seems odd that it is showing this as an error now.
Thanks
Caroline
Caroline,
Unfortunately every wheel has its own individual sensor-transmitter-battery unit which has to be replaced, requiring wheel and tyre removal and subsequent rebalancing.
It's not an official service item so unless a TPMS error was flagged-up I doubt that Brooklands would have replaced the units. Although TPMS battery life has improved in the past 6-years I would imagine that yours will need to be replaced in the not too distant future ... maybe when you next replace the tyres would be a good opportunity.
Jeff
Unfortunately every wheel has its own individual sensor-transmitter-battery unit which has to be replaced, requiring wheel and tyre removal and subsequent rebalancing.
It's not an official service item so unless a TPMS error was flagged-up I doubt that Brooklands would have replaced the units. Although TPMS battery life has improved in the past 6-years I would imagine that yours will need to be replaced in the not too distant future ... maybe when you next replace the tyres would be a good opportunity.
Jeff
Another thought, change the wheel type to winter, drive 15 mins, then back to summer, drive 15 mins. That will reset the system.
Thanks all, I'll bear all that in mind. I will try the PSI and winter/summer settings changes as well if the problem is still there when I next drive the car.
BTW in the mean time what would you recommend if I see the warning again, is it worth putting a bit more air in the tyre(s) it says are low anyway, even if the readings show the same pressure on both sides?
Trust your tyre pressure gauge if you have one.
Ha! I had an electronic one but the batteries have run out on that too, so maybe time to get some more (hopefully cheaper ones than the TPMS ones!) for that, or maybe a new (mechanical) gauge as frankly I never really got on with the electronic one too well - I could never get it to seat properly on the valve so never really trusted the readings anyway.
Having read this thread and investigated the subject, I asked my OPC about this today. My car is a 14 reg, so about the same age as yours, Caroline. They were able to tell me that my batteries have a projected life left of 120 months. In other words, a total life of 16 years.
How they can tell the remaining life, I haven’t a clue!
How they can tell the remaining life, I haven’t a clue!
Graham,
Your man-maths is only partially correct. It's a 2014 car, so if the batteries are supposedly going to last another 10-years that's 16-years in total.
Having said that, I wouldn't have much confidence in Gordon's Porsche Centre's optimistic prediction. Looking online, the average life of TPMS batteries appears to be about 7-years.
The direct TPMS system uses battery-operated pressure sensors and transmitters in each wheel the signals from which are picked-up on a body-mounted receiver, so I suppose it's possible that the individual battery states are included in the transmitted information which can be accessed via the PIWIS system?
Jeff
Your man-maths is only partially correct. It's a 2014 car, so if the batteries are supposedly going to last another 10-years that's 16-years in total.
Having said that, I wouldn't have much confidence in Gordon's Porsche Centre's optimistic prediction. Looking online, the average life of TPMS batteries appears to be about 7-years.
The direct TPMS system uses battery-operated pressure sensors and transmitters in each wheel the signals from which are picked-up on a body-mounted receiver, so I suppose it's possible that the individual battery states are included in the transmitted information which can be accessed via the PIWIS system?
Jeff
Quick update, this is still showing as an error this morning, but again the absolute pressures were fine. In the end I didn't really have time to fiddle about with the settings but frankly I think I'm going to ignore it unless either the absolute numbers look odd or the pressures are definitely wrong on an analogue pressure gauge.
The car is going in for its MoT at Brooklands at the end of the month so I will ask them about it, and the battery life on the TPMS system, then.
The car is going in for its MoT at Brooklands at the end of the month so I will ask them about it, and the battery life on the TPMS system, then.
The Tpms batteries on my 2010 turbo nearly reached 10 years. Bought a replacement set from Germany at half the cost of PC prices!
Very unlikely batteries would last 16 years!
PC can detect remaining battery life.
I would try reset as mentioned above then, if unsuccessful, try swapping the wheels over. That way you would find out if it's dodgy sensors or faulty control module. Either way the PC should be able to determine where the fault lies when if goes in for MOT![]
Very unlikely batteries would last 16 years!
PC can detect remaining battery life.
I would try reset as mentioned above then, if unsuccessful, try swapping the wheels over. That way you would find out if it's dodgy sensors or faulty control module. Either way the PC should be able to determine where the fault lies when if goes in for MOT![
]
tscaptain said:..... Either way the PC should be able to determine where the fault lies when if goes in for MOT![
Be very careful on this point, most dealers including Centres do the MOT before the service even if a fail condition is reported in advance and repair requested, so you get a MOT fail on the car's record.
Apparently a TPMS malfunction became a major defect in May 2019 and will result in an MOT failure, although I would imagine that a fault warning light would have to be displayed for this to be enacted?
It's not clear to me if Caroline's getting a warning message and warning light [splitting hairs maybe], but I've a feeling that the problem will have to be cleared before an MOT is given. Probably best to inform the Centre in advance to discuss the issue. Unfortunately it could turn out to be an expensive MOT. []
Jeff
It's not clear to me if Caroline's getting a warning message and warning light [splitting hairs maybe], but I've a feeling that the problem will have to be cleared before an MOT is given. Probably best to inform the Centre in advance to discuss the issue. Unfortunately it could turn out to be an expensive MOT. [
]Jeff
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