Cruise control issue

I have my 2023 Toyota Tacoma TRD sport since February 1923 right after I got it I replaced the grill and put a 22 TRD grill in it. 13 months after I change the grill, I was driving on the interstate and noticed that the cruise control was not working properly You would not automatically slow the vehicle down when I approached a slower moving vehicle on the interstate. I took it to the Toyota dealership, and they said the reason that it was not working, is because I changed the grills I told the tech that I had the grill in there for 13 months and it been working properly. Any idea what changed and why it’s not working now

 

You do realize that there are 2 settings for cruise control - one uses sensors to match the speed of the vehicle in front of you and the other sets a fixed speed.
What other things have you modified or changed/added in those 13 months?

 

I do know that there’s two different settings. It acts like it’s always in constant speed mode. I’ve haven’t done any changes to the grill in the last 13 months. The dealership said that the reason that it didn’t work was because the sensors mounted in different spots on the different grills and they wanted to charge me $1800. I told him it worked for 13 months and I didn’t understand what the sensor had to do with it not working now when it worked before

 

Operating in the constant speed mode, or the sensor might be dirty?

 

The radar sensor technically needs to be replaced with a different part and calibrated when you replace the grille, if you do it "by the book". Most people don't do either when replace grilles, and they seem to have no problems. I decided to replace the sensor, and I wrote a thread on DIY calibration (short answer is I don't recommend it, but it can be done). https://www.tacomaworld.com/threads/diy-radar-sensor-calibration.838975/

I previously had issues with my sensor intermittently not working, but it would always throw an error. I think it got water in it or something. I'd have to manually select non adaptive cruise (long press the cruise on/off switch).

The only time I've seen adaptive cruise completely revert to constant speed without warning is when the sensor is obstructed by rain, ice buildup, snow, etc. I've also seen it happen occasionally on unusual size/shape vehicles, but it's rare.

When I replaced the sensor, there was a persistent error (taking over the screen every 7 seconds), and cruise control was not available at all until I did the calibration.

You could start by checking that the sensor is still securely installed, and remove it to make sure no spiders got between the sensor and the emblem.

Have you made any other changes recently that in combination with the grille could change the angle enough for it not to work? For example changing ride height, or putting a lot of load in the bed?

 

You're lucky they didn't purposefully brick your radar unit when they saw the aftermarket grille. There's a TSB out there instructing dealers to do that.

https://www.tacomaworld.com/threads/tsb-0026-20.836601/#post-29961734

Not sure why it worked for a certain time then got unhappy but they're aware of it now. Unless your Tacoma is a Pro and came with the Pro grille, anything else is aftermarket the dealer will not cover fixing or recalibration for.

That radar sensor is used for collision and active (distance based) cruise control. Just curious, does long pressing the CC button still let you enable the constant speed CC or is it fully disabled?