TPMS sensor, curious what they look like?

[Steve44]

I had a damaged wheel which I had replaced today with another, 2nd hand but better one sourced from eBay. It came with the TPMS sensor still attached and Lexus have swapped it for me as easier than recoding the sensor to the car. So I now have a spare sensor and a spare wheel!

In case anyone was curious what they looked like or details on them, here it is. Looks completely non serviceable. Battery is sealed in.

[NemesisUK]

Have a read of this thread, batteries can be replaced..

 

[Steve44]

Appears so, though the IS one doesn’t have the extra plastic cover, just the clear rubber across the Battery and circuit board. 

[ganzoom]

The sensor batteries are suppose to last 10 years+

[Britprius]

11 hours ago, Steve44 said:

Appears so, though the IS one doesn’t have the extra plastic cover, just the clear rubber across the battery and circuit board. 

Steve the Battery is under the white sealant, and this can easily be carefully dug out and the Battery removed, and replaced as in my earlier post. This will make the unit usable again saving a considerable sum.

The life span of the batteries is variable possibly dependent on how long the Battery was made before being fitted to the sensor, and how long the sensor stood before being fitted to a wheel, and car. The batteries have a self discharge rate meaning they discharge even when not in use. Even this varies dependent on temperature, and humidity. The real world life seems to be around 7 or 8 years.

John.

[matt8]

What are the logistics of getting all four sensors out, so you can do DIY on your TPMS Sensor?

Surely you'll need a cooperative tyre fitter who will let you have the sensors (for a few hours perhaps) between removal and refitting of the tyres?

Aren't tyres damaged during removal, usually?

[Britprius]

13 minutes ago, matt8 said:

What are the logistics of getting all four sensors out, so you can do DIY on your TPMS Sensor?

Surely you'll need a cooperative tyre fitter who will let you have the sensors (for a few hours perhaps) between removal and refitting of the tyres?

Aren't tyres damaged during removal, usually?

Standard rubber valves can be fitted "if required" while you service the sensors allowing continued use of the car.

The tyres do not need to be removed from the wheels to change the valves. Pressing the tyre outer wall from the rim on a tyre removal machine gives enough room to remove the sensors after undoing the outer holding nut. A rubber valve can the be fitted, and the tyre re-inflated. This means the tyre is not rotated on the rim, and does not need balancing.

My local tyre fitter was happy to do this for £5 per tyre including re-fitting the sensors after Battery replacement

For those with cars over about 6 years old it would seem prudent to replace the batteries in the sensors when having new tyres fitted "initially fitting rubber valves to allow time for servicing the sensors". I am sure if asked most tyre fitters would be happy to then refit the sensors when serviced free of charge having sold you new tyres. 

John.

[matt8]

 

6 minutes ago, Britprius said:

This means the tyre is not rotated on the rim, and does not need balancing.

I'd have thought removal of the sensor would cause the need for rebalancing? Perhaps for just a short while, it'd be OK?

 

Is this TPMS Battery swap job is risky?

I like to take care of things proactively, but if you damaged the sensors during a precautionary Battery swap, you might be kicking yourself for messing with them.

[Steve44]

The damaged wheel I got back with the original tyre and they put a rubber valve in it as stated above. It will do as a spare for me for now, or could be repaired in the future (would need welding and turning and repainting) and the valve replaced.

lexus said it is easier to swap the valve than recode it. However, if you don’t have a valve in place I guess the car still throws up a ⚠️ sign? Which would be a MoT failure now too. Can that be coded out?

How much is a new TPMS valve to buy now? Guessing £60-80 each?

[Britprius]

1 minute ago, matt8 said:

 

I'd have thought removal of the sensor would cause the need for rebalancing? Perhaps for just a short while, it'd be OK?

 

Is this TPMS battery swap job is risky?

I like to take care of things proactively, but if you damaged the sensors during a precautionary battery swap, you might be kicking yourself for messing with them.

Changing the batteries in the sensors is easy with a little care. Fitting the Battery with the wrong polarity is possibly the only thing you can do wrong. Even this is not catastrophic as fitting your 12 volt Battery wrongly would be. Being able to handle a soldering iron is also useful.

Having tried the swap to rubber valves after removing the sensors I had no problems with wheel balance vibration "the weight difference is minimal". As you say though this is only for a short period perhaps over a week end the thing is to make sure you have the new batteries ready to fit in the sensors.

John.

[Britprius]

1 minute ago, Steve44 said:

The damaged wheel I got back with the original tyre and they put a rubber valve in it as stated above. It will do as a spare for me for now, or could be repaired in the future (would need welding and turning and repainting) and the valve replaced.

lexus said it is easier to swap the valve than recode it. However, if you don’t have a valve in place I guess the car still throws up a ⚠️ sign? Which would be a MoT failure now too. Can that be coded out?

How much is a new TPMS valve to buy now? Guessing £60-80 each?

On newer cars a TPMS warning light would be an MOT failure, but on vehicles made before I beleave 2012 "could be 2014" it is not a failure as TPMS on the earlier cars is not compulsory.

John.

[Thackeray]

On 3/16/2019 at 11:57 AM, Britprius said:

on vehicles made before I beleave 2012 "could be 2014" it is not a failure as TPMS on the earlier cars is not compulsory.

2012 is right. Here's what the MOT handbook says:

The inspection of the tyre pressure monitoring system (TPMS) is for M1 vehicles first used on or after 1 January 2012.

The TPMS warning lamp (see diagram 3) can operate in many ways depending on the vehicle type. You must only reject vehicles if it's clear that the lamp indicates a system malfunction and not simply indicating that one or more of the tyre pressures is low.

 

That sounds open to interpretation. Is it a system malfunction if you haven't got a TPMS valve in one or more tyres? And how can the tester easily tell whether a tyre has low pressure. Are they going to go round checking what the tyre pressures are? Then inflate any that are low. Then reset the TPMS system to see if the light goes off?

[NemesisUK]

I thought the TPMS light flashes if there is a system error, not simply illuminates as it does to warn of low pressure?

[malcolmw]

The TPMS warning light flashes orange for a few moments and then stays on permanent orange if there is a system fault. It shows red for a tyre pressure fault thus differentiating between the modes.