Help! - Parking sensors?

K20FTY · March 3, 2019

Seems a bit of an odd one to me, but here goes...

I have a 2006 IS250 SE, without NAV, it has physical sensors in the rear bumper, (none in the front), but the car doesn’t beep when selecting reverse, or when reversing towards an object (even a solid wall), and I’ve never seen the green parking assist light on the dash.

There’s the correct fuse in the passenger footwell fuse box, and it’s not blown.

I’ve read about a ‘switch’ in the boot to turn it off if you’re towing a trailer, but can’t find any sign of one (unless it’s hidden under a trim panel), and there’s no sign of it ever having a tow bar fitted.

Anyone got any thoughts on what’s going on, or know if it’s something that a dealer could have turned off? (If so, could I buy tech stream & turn it back on?)

Thanks in advance!

Texas · March 3, 2019

On your 'Satellite' switch ( as Lexus call it) is the parking assist ON?

Paul m.

K20FTY · March 3, 2019

On your 'Satellite' switch ( as Lexus call it) is the parking assist ON?
Paul m.

K20FTY · March 3, 2019

Sorry, fat fingers & hit reply too soon - my satellite switch only has options for speed & tach...

Texas · March 3, 2019

So in that menu list it does say ( If Equipped) after Parking Assist and some others but not after the Speed & Tachometer Indicator feature,

So I guess All cars have the Speed & Tachometer feature and the other features are options, therefore could it be possible that your car has been fitted with a replacement rear bumper at some point that has sensors in it from a car that had this feature and your car does not?

Paul m.

K20FTY · March 3, 2019

So in that menu list it does say ( If Equipped) after Parking Assist and some others but not after the Speed & Tachometer Indicator feature,
So I guess All cars have the Speed & Tachometer feature and the other features are options, therefore could it be possible that your car has been fitted with a replacement rear bumper at some point that has sensors in it from a car that had this feature and your car does not?
Paul m.

Thanks Paul - you’ve come to the same conclusion I did - I can’t think of any other reason than a new bumper at some point... :(

K20FTY · March 3, 2019

Thanks Paul - you’ve come to the same conclusion I did - I can’t think of any other reason than a new bumper at some point... :(

And to answer your first question, yes, the only options available are speed & tach - I have none of the others listed, so they must all be options

Texas · March 3, 2019

Bit disappointing and annoying I reckon. Also because of the massive amount of wiring looms, ECU's and sensors in the IS ( even on the base level trim models) it would be very difficult to retro fit any feature like this without causing possible huge problems with the original systems.

paul m.

johnatg · March 3, 2019

Not so fast - mine has the parking sensors at the rear - not at the front - but it doesn't have a light on the dash to say parking assist is working, it doesn't show up on the multi-information display, it doesn't show up on the satellite switch settings (only speed and tach are there) and it doesn't beep when selecting reverse.

But it does beep (progressively faster) when you reverse up to an object.

I can't just think of what Ian can check, but don't give up yet!

K20FTY · March 3, 2019

Not so fast - mine has the parking sensors at the rear - not at the front - but it doesn't have a light on the dash to say parking assist is working, it doesn't show up on the multi-information display, it doesn't show up on the satellite switch settings (only speed and tach are there) and it doesn't beep when selecting reverse.
But it does beep (progressively faster) when you reverse up to an object.
I can't just think of what Ian can check, but don't give up yet!

Hmm...that’s very interesting, thanks - I’m wondering if Techstream might ‘find’ them? I haven’t invested in it yet, so now might be the time...

Texas · March 3, 2019

So..there is no way of knowing it is working or 'on' as such until you get close to an obstruction?

can't understand why there would Not be a visual indicator of some sort even if it was just when beeping.

Paul m.

johnatg · March 3, 2019

That's right.

Incidentally they don't work when covered in snow and ice.

Sent from my PSP7551DUO using Tapatalk

johnatg · March 4, 2019

Here is part of the circuit diagram for the clearance sonar system, along with parts location diagrams. Lexus seem to regard Clearance Sonar and Parking Assist as two distinct parts of an overall Parking Assist/Monitor system

There is an extra part of the circuit diagram when the sonar system is linked to the parking assist functions, but I don't think that applies to Paul's and my cars.

There are lots of pages of the workshop manual dealing with trouble shooting and testing and settings, but they all require the Intelligent Tester - that's a bit of kit which dealers have which is used for all sorts of things. It is not the same as TechStream which I don't think will help here.

Intelligent Testers come up for sale occasionally, but they cost about £300.

K20FTY · March 6, 2019

Here is part of the circuit diagram for the clearance sonar system, along with parts location diagrams. Lexus seem to regard Clearance Sonar and Parking Assist as two distinct parts of an overall Parking Assist/Monitor system
There is an extra part of the circuit diagram when the sonar system is linked to the parking assist functions, but I don't think that applies to Paul's and my cars.
There are lots of pages of the workshop manual dealing with trouble shooting and testing and settings, but they all require the Intelligent Tester - that's a bit of kit which dealers have which is used for all sorts of things. It is not the same as TechStream which I don't think will help here.
Intelligent Testers come up for sale occasionally, but they cost about £300.

Thanks - I’ll have poke around at the weekend & see what I can find...

Thelongterm · March 17, 2022

I have the opposite, I want to disconnect the annoying beeps or at least lower the volume.

I am a big boy and can reverse a live axle trailer in to a tight space without ever damaging anything, done so for over 35 years, I am not sure I like reverse sensors or cameras.