Tire Assistant app shows tyre pressure readings

Thackeray · September 23, 2020

I've just come across an app called Tire Assistant which shows the individual pressure readings for each of the wheels on the IS300h.

It's always been a slight irritation that the TPMS system on the IS300h is only partly helpful. The TPMS warning light tells you there might be a problem with one or more of your tyres but it doesn't tell you which tyre. When it's dark and raining it wouldn't be the best time to have to try and find out which tyre is losing air. This is especially irritating because, as far as I can tell, the car knows which sensor is reporting low pressure. It just doesn't display this information on this car.

So I thought I would try the Tire Assistant app and it seems to work fine. It needs an OBD device and an Android phone. You start the car and then start the app and it looks like this:

The pressure display is initially in bars but it can be changed to psi.

Initially, the app doesn't know which sensor is on which wheel but as the pressures are adjusted at a garage you can identify each sensor by the change in pressure reading. Then each wheel image can be dragged to its correct location and renamed with its location as shown in the video above.

It looks quite useful and saves having to get your hands dirty checking the pressure manually.

Here's the webpage for Tire Assistant.

BrunoLeal · September 23, 2020

Very good! Which OBD device as I only have an USB one to connect to computer?

Thackeray · September 23, 2020

1 minute ago, BrunoLeal said:

Very good! Which ODB device as I only have an USB one to connect to computer?

The Hybrid Assistant website has a page on which OBD connectors work with which cars and which don't. I've just read the corresponding page on the associated Tire Assistant OBD page and they say they have only tested the OBDLink LX. I hadn't read this page until now but my Carista OBD connector worked fine. I didn't notice anything that didn't work properly but it's a very simple app with few functions.

On the Hybrid Assistant page they do list a cable connected device but whether that means it would work with Tire Assistant app, I don't know.

wharfhouse · September 24, 2020

Just tried this with a 6 year old ELM327 OBD reader (one of the cheap ones from amazon - connects with Bluetooth) - it connected and worked and the tyre pressures displayed but then then the app lost connection after a few seconds. Tried again a few times and same - I can get a connection, tyres pressures read and then disconnects. Adjusted pressures in tyres and went for a drive and pressures changes as expected so it does all work other than only displaying for a few seconds. I suspect this is the cheap OBD reader - just wondering if with the Carista OBD connector if this stayed connected ok? If so for £25 I might buy the Carista OBD connector.

Mincey · September 24, 2020

Mincey's Stupid Question Of The Day - I've had a look at the Carista OBD doofer and am very interested. However, if I take the plunge, then subscribe, will I be able to use it to check other cars or is the subscription limited to one specified car?

Thackeray · September 24, 2020

3 hours ago, wharfhouse said:

just wondering if with the Carista OBD connector if this stayed connected ok?

I didn't notice it disconnecting. It seemed to be connected for as long as I wanted to look at it. The app does say it will shut down if you drive the car. I assume you were stationary and the app didn't shut down. Instead, I assume the app said it had lost the connection - this would suggest the OBD device had lost the Bluetooth connection.

2 hours ago, Mincey said:

However, if I take the plunge, then subscribe, will I be able to use it to check other cars or is the subscription limited to one specified car?

I don't think you actually need a subscription - as far as I understand it the subscription is just for the Carista app. The device I used is borrowed so I didn't know anything about the subscription. I've just borrowed it to test the Hybrid Assistant and Tire Assistant apps. Both worked for me without problems and they are both free. If you buy one from amazon you could always return it if it doesn't work for you.

Mincey · September 24, 2020

42 minutes ago, Thackeray said:

I don't think you actually need a subscription - as far as I understand it the subscription is just for the Carista app. The device I used is borrowed so I didn't know anything about the subscription. I've just borrowed it to test the Hybrid Assistant and Tire Assistant apps. Both worked for me without problems and they are both free. If you buy one from Amazon you could always return it if it doesn't work for you.

A good point - I've just ordered one so let's see how it goes!

Thackeray · September 24, 2020

The Hybrid Assistant website says the Carista connector doesn't work with the fourth generation of Hybrid Synergy Drive (HSD4). But the IS300h is third generation and I don't think the facelift version changed that. I hope someone will correct this if I'm wrong.

wharfhouse · September 24, 2020

3 hours ago, Thackeray said:

I didn't notice it disconnecting. It seemed to be connected for as long as I wanted to look at it. The app does say it will shut down if you drive the car. I assume you were stationary and the app didn't shut down. Instead, I assume the app said it had lost the connection - this would suggest the OBD device had lost the bluetooth connection

Thanks - yes car was at a standstill so I think it's my old OBD device - connected, displayed the tyre pressures and then after about 5 seconds disconnected - I was actually surprised it worked at all. I think I'll invest in the Carista one in that case as it's good for other tasks too.

Mincey · September 25, 2020

Oh come on amazon! Don't you know how keen I am to try this out. Why do I never get deliveries from them in the morning. It's not like there's a bloody great big distribution centre about four miles from here....

Mincey · September 25, 2020

It has arrived. How can I slope off from work early...?

Mincey · September 25, 2020

I sloped off. After initially trying to pair the app with the car (which would never have worked), I saw the error of my ways and instead paired the Carista device with my phone. It takes a while for the pressure for each tyre to register, but here's the result. Is it ok to leave the thing in the OBD socket all the time? Now I just need to tell it which tyre is at which corner. It's a bloody good idea though so big thanks to @Thackeray for the heads-up :-)

Now for a weekend of fun trying out the Hybrid Assistant app...

EDIT - my tyres need some puff in them (they should all be 36psi apparently - https://blog.lexus.co.uk/lexus-tyre-pressure-size-guide/)

Mincey · September 25, 2020

To answer my question about leaving it plugged in, and to satisfy anyone else's curiosity, it's basically ok: https://www.amazon.com/ask/questions/TxH2MSLDIMMUMX/ref=ask_ql_ql_al_hza#:~:text=Can the carista obd2 adapter,safely%3F&text=However%2C we still do not,you're not using it.

Thackeray · September 25, 2020

Glad you got it working.

As far as I know there's no problem leaving it plugged in while driving or indeed while stationary.

But I have a couple of queries myself. The link in Mincey's last post raises the question of power drain. I had the impression that it has power whether the ignition is on or not. If that's right, over long periods it might help to run down the 12v Battery. Whether that's a minimal effect or not I don't know.

I also wonder if there's a security risk. If the OBD device is always powered, then it would be fairly straightforward for a thief to connect to it by Bluetooth from outside the car. I don't know what could then be done - reprogram keys? unlock the doors? Maybe someone else with more experience of the OBD facilities can give guidance.

Mincey · September 26, 2020

Just pumped the tyres up - only the offside front and rear were in the wrong position in the app which is easily sorted. The chap over the road who was washing his car kept checking on what I was doing. "Pumping tyres up? On a mobile...?"

wharfhouse · September 26, 2020

1 hour ago, Mincey said:

Just pumped the tyres up - only the offside front and rear were in the wrong position in the app which is easily sorted. The chap over the road who was washing his car kept checking on what I was doing. "Pumping tyres up? On a mobile...?"

Just got my Carista dongle so will check out later. I checked and adjusted my tyre pressures the other day and using the old OBD dongle I had found the offside rear (as that was low) and moved it to the correct position in the app (it was the front nearside originally in the app which I corrected to rear offside). Can you remember which ones did you moved from where to where as I might do that first until I get chance to double check them? Thanks in advance.

Mincey · September 26, 2020

3 hours ago, wharfhouse said:

Can you remember which ones did you moved from where to where as I might do that first until I get chance to double check them? Thanks in advance.

My offside front and rear needed swapping - nearside was fine.

wharfhouse · September 26, 2020

1 hour ago, Mincey said:

My offside front and rear needed swapping - nearside was fine.

OK - thanks - could be different on mine then as I found front nearside had to go to rear offside - will probably have to add/lose some air to confirm in that case.

wharfhouse · September 26, 2020

Tested my new Carista OBD reader with Tire Assistant and it works a treat. Sorted out which tyres are which on the display so all set. The Tire Assistant polls the OBD every few seconds and updates - on my old OBD dongle looks like it got a read first off and then when the next poll happened a few seconds later the Bluetooth connection was lost. I'll have a look later at what Carista offers on the car customisation too now I've purchased it as looks like I get a free month of full features. Thanks Thackeray for the post on the Tire Assistant - very useful.

Thackeray · September 27, 2020

On 9/25/2020 at 3:05 PM, Mincey said:

Now for a weekend of fun trying out the Hybrid Assistant app

Did you try the Hybrid Assistant app?

It generates a lot of interesting information - really far more than you can follow while driving. But it taught me a lot about how the car is working. The website has links to a lot of useful videos on youtube.

Mincey · September 27, 2020

1 hour ago, Thackeray said:

Did you try the Hybrid Assistant app?

It generates a lot of interesting information - really far more than you can follow while driving. But it taught me a lot about how the car is working. The website has links to a lot of useful videos on youtube.

Not yet - I'm still waiting to have a go. I shall gen up on it for next week :-)

One useful nugget (perhaps). My wife's 2019 Ioniq's air con has packed up. I thought I'd try the Carista app to see if i could surprise the service department with a fault code on Wednesday when it goes in for a service, but it didn't really do an awful lot. Just checked one ECU and that was it. When I checked my IS, I got bored waiting for it to check all the ECU's!

Mincey · September 27, 2020

Just had a quick nosey at Hybrid Assistant:

The only professional tool I know isn't at home at the moment...

This is at idle. Probably not that interesting to the majority of you, but all that data and graphics gets me going!

Thackeray · September 27, 2020

I'd read about the different stages the engine goes through as it warms up but have only now been able to see when this happens. That's one of the reasons I found this app interesting.

In the graphic above the engine has recently started and is in stage S1a. This will continue for about a minute and it may stop after that. In this colder weather maybe it wouldn't stop. In this initial stage the engine is low powered with late ignition timing and uses a relatively large amount of fuel - presumably to heat the engine and catalytic converter. (Is that right?) It spins MG1 and produces a small amount of electricity that goes into the Battery. (This is shown with a narrow red band at the bottom of the engine column and a narrow green band at the top of the Battery column. The numbers show power in kilowatts produced by the engine and stored in the Battery.)

I have seen forums where some keen fuel-maximising Prius owners don't drive the car during this stage. This is because the engine isn't used to move the car in this stage. Instead, all power to move the car during S1a comes from the traction Battery. And so, since the Battery is discharging it can't be charged at the same time. So this small amount of power produced during S1a is thrown away instead of being stored in the Battery as happens when the car is stationary. Interesting but I'm not really bothered about such small fuel savings.

You can't select EV mode during S1a. I think this stage ends when the engine temperature reaches 40C.

Before S1a, there's S0 when the car is in Ready mode but the engine hasn't yet started. After S1a there's S1b, then S2, S3 and for normal long distance driving S4.