Aftermarket TPMS

[Guest]

I've got an older Auris, 2009. I recently bought a cheap TPMS system, it has four screw-on sensors that go in place of the valve caps. And a little dashboard gadget shows the temperatures and pressures. I have a few small doubts about the overall design, but more importantly one of the sensors doesn't work and the kit I bought omitted the special tool to "crack" open the sensors to replace batteries.

The seller gave my money back, so I went and bought a second similar looking product that was advertised to come with the Battery replacement tool. Unfortunately, it arrived with the tool missing... and these cheap car parts that do me no good are starting to stack up around here.

Has anybody added an aftermarket TPMS to their car, and is satisfied with it? If so, could you share what product you bought and your results. Thanks.

[ian rooke]

Hi I have a aftermarket TPMS fitted to my Gen4 Prius the dash unit is solar powered the tyre sensors are Battery it came with a  tool to open the sensor it is far better than the manufactures system as it gives a audible warning as well as visual (Toyota warning is visual only over on the passenger side and does not tell you which tyre is faulty )so in my mind is totally useless I fitted the same on to my wife's car and am just as satisfied with that one     

[mrpj]

Yes, I have similar in my car. Solar (when sufficient light available)charging and u.s.b. if required. The small spanner that is included is for opening the sensors and the locknuts. A tamper ring is removed first to reveal a hexagon for the spanner. Seems to work well with both visual pressure and temp. display (dimmable) and audible warning for low/high pressure and high temp..

It was bought from evilbay a couple of years ago. https://www.ebay.co.uk/itm/4-Sensor-Solar-Wireless-TPMS-Car-Tire-Tyre-Pressure-System-Monitoring-External-/313231010759?hash=item48ee05ebc7I wouldn't describe the pressures or temperatures displayed as fully accurate but they are certainly a good reference.

The sensors are a bit chunky and I don't use the locknuts because they tend to seize onto the valve stem thread!

I don't know how many offs and ons of the sensors it will take before the tiny seals fail but so far so good.

[Guest]

7 hours ago, ian rooke said:

... it came with a  tool to open the sensor...

Ian, would you mind sharing the name of the product, or a photo? I am trying to purchase fewer dud products. 🙂Thanks.

[Guest]

I guess I'll share my concerns about the overall design.

1. Heavy. The external sensors screw onto the valve stems and then, at speed, presumably exert a far greater radial force on the valve stem than they were designed for. I saw posts online from people who said the valve stems failed soon after installing the external sensors.
2. Point of failure. The external sensors actually replace the function of the quite secure internal valves, and instead the high pressure is brought all the way up the valve stem and terminated with the sensor valve caps. It seems to me that failure of those little o-rings might be a common problem, especially as the seal needs to be broken every time you adjust the tyre pressure. At least we will get a warning..
3. Metal-on-metal threads. The potential is there to corrode or spall causing the metals to fuse, hence requiring a valve stem replacement when the sensors need to be removed (mrpj alluded to this, as well as an older forum thread where an owner was charged an extra £200 by Toyota). If the threads are greased, then does that then attract dust and grit near the sealing surface, not to mention damaging the rubber seals?

Meanwhile, the pros:

• Flexibility. In theory, with an external system and availability of reliable parts, it should be possible to remove and replace/upgrade the entire system with ease.
• Safety. The difference having an alerting TPMS is that if you have a small puncture or damage while driving, you'll be alerted once you lose ~3psi or so, rather than by the vibration and flapping sounds you won't hear until it's too late, possibly suffering damage or a loss of control.

I'll continue searching for a product that includes the tools for disassembly. There is frightfully little information online about these add-on systems.

 

[Guest]

2 hours ago, mrpj said:

The small spanner that is included is for opening the sensors and the locknuts. A tamper ring is removed first to reveal a hexagon for the spanner....

Thanks mrpj, my second set looks nearly identical to yours. I have confirmed the hex wrench can be used to crack them open (when used with channel lock pliers). I also didn't notice that it could be powered by USB, as I plan to keep the received in the glove box to deter theft.

My set didn't include a USB cable and unlike yours, the instruction booklet is just gibberish.

I think I will swap out my installed system for this and see how it works. The sensors are also 2g lighter. Thanks for sharing the information, maybe I won't have to buy a 3rd set after all.

[ian rooke]

Hi Douglasheld the picture from MRPJ is exactly the two I have 

[Guest]

Wonderful, I think I know the path forward. I will try try the external sensors for a year, and then will perhaps invest in the internal sensors if I have any trouble.

Thanks.

[ian rooke]

Hi I have been using external TPMS sensors for the last 5 years on 4 cars and have not noticed any detrimental effects on the valve stems  

[mrpj]

5 hours ago, ian rooke said:

Hi I have been using external TPMS sensors for the last 5 years on 4 cars and have not noticed any detrimental effects on the valve stems  

I think my issue stemmed (pun intended) from, to my embarrasment, not checking the pressures often enough separately with a gauge and relying on the TPMS display. The locknuts seized on two valve stems which had to be held with waterpump pliers while !Removed! Really! What's wrong with s crewed? off the locknuts. Unscrewed maybe? Same as a male chicken seems to be offensive now. No resulting damage fortunately. Not had any issues since. I do, as is proper, check the pressures (and inspect the tyres) more regularly now. Also no locknuts and  tiny bit of silicone grease on the valve threads.

If anyone is inclined to steal the sensors they are welcome. Of no use to them because they are programmed to the display unit! Unless they smash a window and pinch that, of course.