TPA800 parking sensors

[karl2000]

So, the parking sensors on my 120 have never worked since I had it. Not a big deal, but its on my list to look at.

They seem totally dead, even the button/light just under the steering column doesn't light up.

However, the parking sensors themselves have power - you can feel it if you put your finger on the sensors!

When I was doing other jobs, I had all the front dashboard trim off and all the wires that I could see looked OK, and I checked every inline fuse I could find which were all fine. I also swapped out the control unit for another one, which also made no difference. Fuse box fuses also checked. Front and back buzzers look OK, and I know about the switch in the box in the boot.

But I learnt recently that the TPA800 needs programming when its installed. The car was sat for years with a flat battery before I got it, so I'm wondering if it needs programming.

Apparently the procedure is to plug in the dashboard light/button to another connector hidden somewhere then it starts up in a different mode. Not sure where the connector is though - anyone ever done it?

Or any other ideas?

Thanks!

 

[Tractionman]

Hi Karl, I have same problem, recently had the rear bumper off for something else, so checked through the hidden wiring, no faults. After I replaced the bumper, selecting reverse now gives me a monotone sound for about 5 secs and that's it. My little indicator lights up, but I didn't know about this isolator switch in the back, where ? Days after that the fronts stopped.
No help at all to you, from what I have found they are not very good anyway

 

[karl2000]

Its interesting I'm not the only one to have problems with it though!

From what I understand the switch was optional and its not always fitted - but if its there, its to turn off the parking sensors on the back in case you're towing something. On the left hand side of the boot, nearest the back seat - take that cubbyhole cover off (ie not the jack one, the other one further forward) - and if its fitted, the button is on the back wall in there. While youre there, if you take out the tray, and reach in, you can get to the control unit for it which will be velcro'd somewhere around the wheelarch - can just make sure its plugged in ok etc!

 

[Tractionman]

Its interesting I'm not the only one to have problems with it though!

From what I understand the switch was optional and its not always fitted - but if its there, its to turn off the parking sensors on the back in case you're towing something. On the left hand side of the boot, nearest the back seat - take that cubbyhole cover off (ie not the jack one, the other one further forward) - and if its fitted, the button is on the back wall in there. While youre there, if you take out the tray, and reach in, you can get to the control unit for it which will be velcro'd somewhere around the wheelarch - can just make sure its plugged in ok etc!

Thanks Karl, I didn't even know there was another cubby, will look tomorrow, thats interesting about plugging in the light elsewhere. The owners manual is very sketchy on these, and that light is shown in the centre of a boot in a picture of a car ! I've read of several others having unreliability problems with these. Never had a vehicle with them before, and have managed thus far without graunching something, depending on a fix, I may not bother. Will watch this with interest. Thanks again.

 

[tony rodaway]

I had a similar problem when I bought my 120 over a year ago now.
I would select reverse and just get the flat line beeb as if I was against a wall. I found a cheap alternative on ebay and removed all the old sensors and fitted new ones.
The module box is located we're the jack and stuff are located.
No need to wire up to the reverse lights just go off the original wire loom.
My £8 kit still works perfectly to this day..
I phoned toyota about a replacement sensors but toyota don't sell them as not a Toyota part apparently.

 

[Tractionman]

Yer, I heard that Tony, how mad can that get, the vehicle comes with them fitted from the factory, yet they don't supply replacement parts. How about if I want a new bumper, steering wheel etc.
Toyota don't manufacture ever part fitted to their vehicles, so where does it end ? Madness !

 

[jibberjabber]

It's only one step beyond, while driving in my car with Baggy trousers.

 

[Tractionman]

Pass the blame, and don't blame me, cos here comes the boat only half afloat.

 

[karl2000]

I phoned toyota about a replacement sensors but toyota don't sell them as not a Toyota part apparently.

The TPA800 sensors seem to crop up on ebay from time to time!

 

[Tractionman]

Thanks Karl, assuming iffy sensors, how would I know which or how many, if more than one.
As they are 'daisychain' linked, if the first in line was goosed, I would think that would take down the rest ?

 

[karl2000]

Thanks Karl, assuming iffy sensors, how would I know which or how many, if more than one.
As they are 'daisychain' linked, if the first in line was goosed, I would think that would take down the rest ?

Not sure mate, do you get power on them all? If you put it in reverse, you can put your finger on em and see if they're alive!

 

[tony rodaway]

Yer, I heard that Tony, how mad can that get, the vehicle comes with them fitted from the factory, yet they don't supply replacement parts. How about if I want a new bumper, steering wheel etc.
Toyota don't manufacture ever part fitted to their vehicles, so where does it end ? Madness !

Well at least if toyota don't sell parts u need at least if you do find the will be a lot cheaper at least.

 

[tony rodaway]

Not sure mate, do you get power on them all? If you put it in reverse, you can put your finger on em and see if they're alive!

My opinion is just replace all the sensors as all made at the same time so if you just replace one u may be replacing the other 3 very soon.

 

[karl2000]

As they are 'daisychain' linked, if the first in line was goosed, I would think that would take down the rest ?

Are they definitely daisychained? I haven't seen the wiring but from the installation diagrams it looks like each sensor has its own two wires?

 

[Tractionman]

Thanks guys, sorry late, been down under again (lc).
Tony, that does make sense, will see how it pans out.
Karl, I found the small round rocker switch, which was showing black, switced so showing red, no difference. Not sure what position it should be.
No, I didn't check live, I just checked no stress, pinching, breaks etc. Live check next, but I can't feel anything with finger and covering makes no difference.
Whist under today I thought about what I said about daisy chain, - wrong. You are quite right, I remember disconnecting each one and reconnecting when bumper off.
Strange that the fronts have stopped, which were working.
This has turned into a bit of a hijack, originally your post now trying to solve mine. Sorry.

 

[karl2000]

Not sure what position it should be in either, as I've never seen them working!

What colour is your light on the dashboard, is it on and the same as it was before?

All good info mate - helps us all!!

 

[Tractionman]

Now you're teaching me something else, - what light. As above, all good info, thanks

 

[karl2000]

Now you're teaching me something else, - what light. As above, all good info, thanks

I think the button under the steering wheel has got a light in the middle of it? Maybe someone with a working set can confirm!

 

[karl2000]

Docs I'm looking at - dont know if the troubleshooting one will be useful seeing as you have a system thats somewhat alive. That setup doc implies you can get it to beep error codes out somehow telling you why its not happy!

 

[Tractionman]

Ahh, that light, sorry I took it to mean a light on the dashboard instrument cluster. Will have a look, it was working previously. Its in an odd position, I remember seein a glimpse of it when cleaning interior, but having to shield it wth my hand to get a better look in daylight. I didnt know what it was for, but I know you can press it. Thanks for other info, I'll see what I can make of it.