When i try to use the cruise control it says check pcs and cruise light flashes. Codes C1a05,C1a40 and B2090. The first 2 have something to do with adaptive cruise control and the last code has to do with pre collision system. Tryna findout what the codes mean so i could fix it. Im guessing the sensor has to be realigned. But would like to know wat the codes are to better help. (08 600hL

 

Fixed. C1A05 is brake pedal switch fault. Either connections or switch is bad. Other C code was driver support malfunction. And the B code was hybrid malfunction. All because a faulty brake pedal switch

 

what part was it ? https://www.lexuspartsnow.com/parts/...bracket,,47101 or https://www.lexuspartsnow.com/parts/...bs_vsc,,89510D

Thanks i know old thread

 

I am having the same error code: C1A05

The doc says:
When the brake pedal is depressed, the stop light switch assembly sends a brake pedal operation signal to the driving support ECU. After reception of this signal, the driving support ECU cancels the radar cruise control system. When the driving support ECU detects a problem in the stop light switch circuit, DTC C1A05 is stored.

How did you finally manages to fix it ? By replacing the harness or a brake assy part ?

 

I think this is this assembly
https://parts.lexus.com/p/Lexus_2011...434030110.html


Brake Light Switch - Repair or Replace
If your brake light switch has failed, some symptoms can include: your gearshift lever gets stuck, your cruise control won't cancel, your engine won't crank, and of course, your brake lights won't work. If your 2011 Lexus LS 600h L exhibits any of these symptoms, bring it in to our service department.

It would correspond to the code error description. Now, either the switch is broken or the connectors / plugs are.

 

Just to give some feedback: I received the replacement part today, replaced it and there is no "check cruise control error" popping anymore.
I purchased this part:

On Aliexpress, and while it seems to do the job for under 10$, it really looks cheap and jerky, I would recommend purchasing another brand. I took this one because I thought it was the same as the original one, however the button's head (in orange here on the cheap one) was white on the original one and MUCH smoother to push.