Seatbelt sensor behaviour

[Draxexo]

Hello all, I picked up my 2016 auris touring last week however I’m getting some unusual behaviour with the seat detection.

Firstly, the passenger side rear seat never indicates as occupied/unbelted.

Secondly, when someone is sat in the driver side rear it activates the middle seat as well, and can’t be deactivated when the occupant has left.

Thirdly, the occupancy resets almost every time I start the car, meaning when someone sits in the rear driver side and then leaves, I need to restart the car in order for it to clear, however this only happens some of the time.

Ive attached some pictures, one showing the occupancy when someone has sat in it but since left, and another when restarting the car.

Any pointers would be massively appreciated

[TonyHSD]

Hi, 

does the car beep and annoy you or it’s just the lights on the dashboard? 
What you have described can be a normal behaviour but also can be something wrong with your sensors build into the seats. 
Since you just have bought it Is there any possibility that the seller has washed the seats and messed up your sensors? 
This is something that you need to look at as possible reason for your issues. 

[Paul john]

On mine it takes a couple of min of driving for the occupancy light to go out on startup. Even if no one is in the seat.  
normal behavior

[solero]

The auris does not have any wiring plugs for seated present sensord on the rear seats.

[Draxexo]

19 hours ago, TonyHSD said:

Hi, 

does the car beep and annoy you or it’s just the lights on the dashboard? 
What you have described can be a normal behaviour but also can be something wrong with your sensors build into the seats. 
Since you just have bought it Is there any possibility that the seller has washed the seats and messed up your sensors? 
This is something that you need to look at as possible reason for your issues. 

Yes, it starts beeping after I start driving. Surely though the lights should go out after someone gets out of those seats?

18 hours ago, Paul john said:

On mine it takes a couple of min of driving for the occupancy light to go out on startup. Even if no one is in the seat.  
normal behavior

They are out the whole time, until someone sits in them and then they don’t go out until the car is restarted

16 hours ago, solero said:

The auris does not have any wiring plugs for seated present sensord on the rear seats.

Are you sure? because it senses when I sit in them.

 

As well, the passenger rear never senses anyone in it, does anyone know where the sensors are located?

 

 

 

[solero]

Seat presence sensors are only fitted in the front seats.You cant get to them without ripping up the seats.

You may be able to bypass the sensor. However the seat belt sensors are more likely to be at fault due to frequent use, and it being a sprung switch.

I would try bypassing the seatbelt switches first to try and identify the culprit.

[Draxexo]

7 hours ago, solero said:

Seat presence sensors are only fitted in the front seats.You cant get to them without ripping up the seats.

You may be able to bypass the sensor. However the seat belt sensors are more likely to be at fault due to frequent use, and it being a sprung switch.

I would try bypassing the seatbelt switches first to try and identify the culprit.

I see, so when I sit in the rear seat is that not a seat presence sensor? Or what sensor is responsible for when I sit in the rear?

 

To add to this, I was doing quite a lengthy drive yesterday and saw the rear passenger side presence light up momentarily. I’m thinking it’s the connection or something to do with the wires in the seats at the back. Where can I find the connectors for the seats at the back?.

[solero]

Correct, rear has no seat presence sensors. I swapped my rear seats and there were no wiring plugs.

Maybe it thought it detected a rear seat belt unplugging whilst driving. You can lift the rear lower bench seat to see the seat belt wiring.

[Draxexo]

15 hours ago, solero said:

Correct, rear has no seat presence sensors. I swapped my rear seats and there were no wiring plugs.

Maybe it thought it detected a rear seat belt unplugging whilst driving. You can lift the rear lower bench seat to see the seat belt wiring.

I see, I’ll take a look later today. So how does it know I’ve sat in the seat then? Because as soon as I sit in the seat the light turns on to show that I’ve sat in the rear drivers side and middle seats. 
 

Do you know where I’d find the wiring along the seat?

[solero]

Just lift up the bench and the wiring will be plain to see.

Surely if your auris has seat sensors, there will be wires leading to it.

 

[Derek.w]

Hi Tomas, What happens if you just plug the seat belts into its socket without any passangers in the rear seats when driving. Or just buckle up the empty seats.

WORTH A TRY.

[Cyker]

That's what I have to do with my bag, as it sets off the seat sensors otherwise!

It's saved it from being thrown into the back of my seat when I've had to brake sharply though!

[Draxexo]

11 hours ago, Derek.w said:

Hi Tomas, What happens if you just plug the seat belts into its socket without any passangers in the rear seats when driving. Or just buckle up the empty seats.

WORTH A TRY.

Then the seats don’t light up, but it’s inconvenient to have to have them plugged in

[koji]

On 7/4/2024 at 9:19 PM, solero said:

Correct, rear has [...]

Hi solero,

where did you get these electrical schemes?

are they for sale?

 

[solero]

3 hours ago, koji said:

Hi solero,

where did you get these electrical schemes?

are they for sale?

 

I downloaded in bulk from TiS on an hourly subscription. Im sure ive seen scanned copies doing the rounds. If i find a link will paste in forum.

[Monarchjock]

I have had an issue with the rear seat warning lights where randomly all 3 would come on at startup and  would beep.If nothing was done the beeping would eventually stop but the lights would stay on. The usual way to sort it was to switch off immediately and start again. They came on a few times while driving. After seeing this post I decided to do something about. I took the back seat out and I can confirm there is no sensor to detect if the seat is occupied. Wiring looked ok, so decided to take one of the seat belt locks apart. There is a sliding mechanism that operates a switch. Couldn't really tell if the switch was just a mechanical micro switch. When I moved the sliding mechanism back and forward the warning lights operated in a strange manner. It wasn't just one light that would go off and on. It seemed to go in a binary count i.e. 00 01 10 11 etc. I then sprayed some WD40 all over the mechanism. Did the same on the second. Third one was too difficult to open so just sprayed the internals and operated the seatbelt a few times.Lights operated as expected this time. So far I have not had the warning lights come on when they shouldn't. 

Can someone explain how the system works if there are no seat occupancy sensors!!!!? I don't often have someone in the back seat to see if that really does happen. I have had someone who undid their belt before the car was stopped and the alarm came on.

I also noticed the bracket that holds the middle and left locks was the wrong way round. i.e. The middle lock was facing right and the left lock was facing to the middle which made putting them back awkward. I will sort that out another time.

[solero]

I think its initiated by the rear door switch. Atleast it is on mines.

Maybe the system is used to fire the rear seatbelt tensioners in an accident.

Seems like it also warns of a released seat belt whilst driving.

Sounds like your seat belt switch was stuck and it was warning you with an error code as to which switch is faulty.