Low tyre pressure warning

[GrahamG]

After a spell of high speed driving I am getting the low tyre warning. When  I clear the message by holding the appropriate button for 3 seconds the warning [written warning and red warning triangle] disappears and stays off for low speed driving.

It is almost as if it is detecting 'high pressure' because it comes on again after a sustained period of high speed driving when the tyres have warmed up.

Needless to say the pressure in all four tyres is as it should be.

My system measures the roundness of the wheels and does not have the more modern pressure transponders in the wheels.

Any advice on how to sort this false alarm.

 

[Guest]

Are you supposed to drive for 30 mins after pressing the button? That's how it works in the other half's h**da

[GrahamG]

Yes Sean you are right. Should have driven the car for 20 minutes after the reset according to Lexus Guildford though nothing in the manual about that.

Problem is now cannot get it to reset. Will try a few more psi in each tyre.

If it is a faulty ABS actuator then that will be £2,500. Guildford see about one a year of the 250 cars they service.

Will check with a MOT inspector if the light on is a fail.

[jonthetourist]

Are all your tyres matching? I haven't seen my warning light since I bought a matching set.

[GrahamG]

No, all four tyres are not matching. A pair on both front and back axle. It has been like that for two years without problem.

All in good condition with plenty of tread, 5mm back pair and 6mm on front. Bridgestones and Avons.

[Britprius]

5 hours ago, GrahamG said:

Yes Sean you are right. Should have driven the car for 20 minutes after the reset according to Lexus Guildford though nothing in the manual about that.

Problem is now cannot get it to reset. Will try a few more psi in each tyre.

If it is a faulty ABS actuator then that will be £2,500. Guildford see about one a year of the 250 cars they service.

Will check with a MOT inspector if the light on is a fail.

A TPMS warning light is not an MOT failure or part of the MOT for cars registered before 2014.

John.

[GrahamG]

Thanks John, I hoped it would not be a fail for cars built before TPMS was mandatory.

[Hadrian]

9 hours ago, GrahamG said:

Thanks John, I hoped it would not be a fail for cars built before TPMS was mandatory.

Out of interest,  when did TPMS start to be used in cars ?

[steve2006]

11 hours ago, Hadrian said:

Out of interest,  when did TPMS start to be used in cars ?

Dunno but I bet google does 🙂

 

[Hadrian]

😂  🤣

 

[Guest]

Yes Sean you are right. Should have driven the car for 20 minutes after the reset according to Lexus Guildford though nothing in the manual about that.

Problem is now cannot get it to reset. Will try a few more psi in each tyre.

If it is a faulty ABS actuator then that will be £2,500. Guildford see about one a year of the 250 cars they service.

Will check with a MOT inspector if the light on is a fail.

Paint over the light with black paint if - the light is visible they might fail it (theory being if it's there it has to be working). If they can't see it they can't inspect it. If abs was faulty you'd get an abs light.

 

You could also scan the codes and see what comes out before wasting 2.5k

 

Sent from my STV100-4 using Tapatalk

 

 

 

[GrahamG]

Tried some extra pressure in the tyres but still the warnings come on.

Google confirms the light on is not a MOT fail for a 2004 car. 

I now have a piece of black tape over the red triangle and will live with £2500 in my pocket.

Will ask Paul Frost how much he wants for a scrap ABS actuator but it is bound to be too much. 

[Guest]

4 hours ago, GrahamG said:

 

Google confirms the light on is not a MOT fail for a 2004 car. 

I now have a piece of black tape over the red triangle and will live with £2500 in my pocket.

[BigBoomer]

What pressures are you running?

[GrahamG]

Had been running at 33psi and then tried in vain 36psi [measured cold].

See little point going higher for my low speed and low load driving.

There is a Youtube video of someone changing over a second hand ABS controller on a Toyota Camry and it is very straightforward.

Unfortunately on my Ls430 the controller is jammed against the bulkhead and a changeover would include the whole pump unit with its pressure pipe connections to each wheel, master cylinder etc, which is beyond my ability. A pity because complete units can be had for about £200 on eBay.

[BigBoomer]

I just read up on indirect TPMS systems and it seems that they compare the rolling radius between wheels.
So, I suspect that you have one (or more) tyres that have a very different rolling radius from the other(s).
This could be from mixing different tyre types, or just one tyre is very worn.
Either that or else one of the ABS sensor rings is damaged or dirty.

https://en.wikipedia.org/wiki/Tire-pressure_monitoring_system#Indirect_TPMS

[Malc]

oh for the joy of us old'uns with simple Ls400s and zero TPMS

pray tell, what is the actual real advantage of TPMS  ?

does it outweigh the disadvantages seen here I wonder ....................

Malc

[The-Acre]

45 minutes ago, Malc said:

oh for the joy of us old'uns with simple Ls400s and zero TPMS

pray tell, what is the actual real advantage of TPMS  ?

does it outweigh the disadvantages seen here I wonder ....................

Malc

I reckon the real advantage is that people like you and me can revel in the knowledge that we'll never see that light on our dash!  I realise it can (if it's not faulty) give you a warning that a tyre is loosing pressure on a motorway for example, other than that, no thanks.

[BigBoomer]

On a car they are useful as they warn you that you have a flat BEFORE you lose control of the vehicle.
Gives you time to come to a controlled stop and check the pressure/call the RAC/AA/GF.

I have TPS on one of my motorcycles and on that they are a lifesaver.
Ever tried to ride a bicycle with a flat front tyre?
Now try that again at 60Mph!!!

[Malc]

6 hours ago, BigBoomer said:

Ever tried to ride a bicycle with a flat front tyre?
Now try that again at 60Mph!!!

BUT YOU CAN DRIVE A CAR TO A CONTROLLED STOP WITH A TYRE GOING FLAT ............... if you have a sudden blowout you will know that whether or not you have TPMS

Malc

[Tulpen]

Now, now, Malc………..we all know you love the 400 and I, for, one really enjoy your adoring posts; but please don't turn into a Luddite - there are enough of those around already. TPMS has been mandatory on all cars for a few years now, and it does save lives. 

It's called progress  😊

[Cotswold Pete]

3 hours ago, Tulpen said:

It's called progress  😊

Agree it is progress, so long as system works as intended, and no doubt means you do not need to check as part of the weekend checkovers I do.

Had a puncture on mine a few weeks ago, it went from 35PSi to 10PSi over 5 miles, and could tell there was something wrong just driving the car.

I assume where TPMS is real benefit is high performance cars which are driven nearer the envelope and you want to know if anything out of kilter is going to see you flying off the road at the next corner.

 

[Malc]

a buddy has a Jaguar big big 4WD thingy , nearly new and his TPMS shows a constant problem when one of his tyres is down 0.5 psi and the others are ok . ... he's a bit fed-up with it tbh

Malc

[BigBoomer]

They can be a PITA if setup incorrectly like the Jag one Malc mentions.
On my 1400GTR it warns me when tyre pressure goes below 36psi (normal = 42psi) and has been a lifesaver on 3 occasions.
It is a properly quick bike (0-60 = 3secs, 1/4mile = 10.7secs) so I really want to know that the tyres are OK before I unleash the beast.

On cars, yer right, you are less likely to crash unless you have a blowout, but so many car drivers NEVER check their tyre pressures that just having compulsory TPMS probably reduces emissions by a few % all by itself. Personally I check tyre pressure on all my vehicles weekly, even those with TPMS.

There are good and bad technologies in most vehicles. I hate the fact that if your Lambda sensor heater becomes less efficient (slow to preheat), the LS430 disables ASC and traction control,..... for a cold start emissions measurement issue. It doesn't actually affect the emissions as once warmed up the lambda sensor performs normally, and for this it disables 2 safety systems? DOH! I also hate linked brake systems on motorcycles, but accept that for new riders or the less competent, they are a boon.

[Tulpen]

On the 460, you can select the individual tyre pressures on the display screen. A couple of years ago, I had a TPMS warning - one of the pressures had dropped about 6psi. When I checked the tyres there was nothing apparent but, having identified the offending tyre, I found a bloody great nail buried in the tread. I was due to go on my annual pilgrimage to the UK the next day and had already done my 'pre-trip check' earlier in the day. Without the TPMS, I would have, eventually, noticed the car behaving strangely. Or the tyre could have gone flat overnight on the ferry...…...causing hassle and peeing off a load of passengers while I unloaded the boot to get to the spare.

It is easy to make a case for NOT having a safety device. I'm old enough to remember the drink-driving law being introduced and remember cries of 'Rubbish, I drink 10 pints a night and it doesn't affect me'...…...or the seatbelt law (I'm not wearing that bloody thing - I could get trapped in the car when it's on fire.)

I owned, and loved, a 400 for 15 years. I've never owned or driven a 430 which is why I don't comment on it. I'm glad you enjoy your 400s - I did - but I enjoy my 460 more. And I speak from experience - not hearsay. Those of you who had a 460 and went back to a 430/400 did it from choice and I respect that.

Just saying 😊