Cruise control automatic braking

[DewyAU Lurker Find all posts View Profile Close DewyAU]

I’m looking at buying a new VX, and was test driving a GLX yesterday but the cruise control exhibited some weird behavior.. the ACC worked fine when there was a car in front maintaining distance and speed down hills, but if there was no car in front the cruise control would not maintain the set speed down a hill. If I reduced the set speed the prado would brake and capture the new speed and then race away down hill again...

As this was a test drive / demo, quite possible operator error is at fault.. having driven modern cars with cruise control with brake assistance I was expecting the prado to hold the set speed even down a hill.

Is the MY21 prado cruise control meant to automatically apply brakes to not over run the set speed? Or is this normal behavior where by brakes are only applied to achieve a new set speed and then the vehicle is allowed to overrun on a steep decline?

we use cruise control a lot and any advice is appreciated..

[cbp Junior Member Find all posts View Profile Close cbp]

I have a new GXL and on a recent trip noticed that I was doing 125+ km/hr down a hill when the cruise control was set for 110.
This doesn't happen in my little manual Captiva. Engine slows down.

[GeeWhizz Senior Member Find all posts View Profile Close GeeWhizz]

Strange behaviour. Admitted, ours is a 2016 GX, without a lot of the anti-everything fruit that the later GXL & + carry. When going down hill with cruise control, the gearbox drops down a cog or two to hold the speed down. And without the cruise control switched on, the same happens when you touch the brake pedal a couple of times, as long as you don't touch the accelerator.

[DewyAU Lurker Find all posts View Profile Close DewyAU]

Thanks for the responses.. over speeding in a vehicle with adaptive cruise control is not expected, especially since the brakes are indeed interfaced with the cruise control. These newer engines almost have zero back compression so brakes are required for even a mild decline.. I’ll ask the dealer for more information.

[Tony76 Junior Member Find all posts View Profile Close Tony76]

The adaptive cruise on the prado is not the best. It will apply brakes if following or catching another vehicle on the freeway etc. but it will not brake itself for runaway on a downhill slope.

Pretty crap programming on Toyota’s behalf as even my old 2013 VW Passat with adaptive cruise was capable of that.

[Leethal Advanced Member Find all posts View Profile Close Leethal]

My 10/18 build VX maintains close to set speed down the gateway bridge in Brisbane as well as the Clem 7 tunnel, both are 80km/hr speed limits