LEX ES300

Mine just coasts downhill no engine braking at all. I hate it. I am convinced it is not meant to do this but i never got to the bottom of it. Still unresolved. Here is a thread i wrote about it a while ago. I replaced the engine ecu myself and still no engine braking. I want it to brake downhills becuase i can just coast at high speed downhills and have to ride the brakes all the time no matter what gear it says im in. Dangerous in my opinion.
https://www.clublexus.com/forums/ls-...ing-issue.html

jpv7774

Huh.....ya I dont want mine to be wide open.....I agree ...without any assist the big heavy sedan would be tough to control on a steep down hill. My work truck is like that and I have warped rotors. Every time I visit this particular area with a massive downhill I have to pump the brakes the whole way down and there is no way I could actually come to a complete stop.......So you made me feel better about having engine braking.....I just wish it wasnt so extreme. Post back once u figure out the fix for yours

StanVanDam

My 2002 UL w/laser cruise downshifts on a downhill if I tap the brakes or hold the brakes. It will continue to engine-brake until I tap the accelerator. If I go downhill and do not tap the brakes, the car will coast and gain speed.

This performs exactly as the engineers designed:

* To reduce both brake fade and brake wear on a long, steep hill, the Super ECT’s brain will tell it to kick-in engine braking to help the ventilated, extra-large, four-wheel disc brakes.

* Comparing the LS430 A650E to the LS400's transmission, the automatic downshift during downhill driving has been expanded to the 3rd and 4th gears to improve driveability

* A650E Road Condition Support Control: While driving downhill, because the transmission is upshifted when the throttle valve is almost completely closed, the transmission upshifted quickly even at low driving speeds, occasionally creating a condition in which it was difficult to apply the engine brake.

Therefore, in the road condition support control, the uphill or downhill driving conditions are assessed through the throttle opening angle, vehicle speed, etc. to achieve an optimal and constant driving force by restraining the transmission from upshifting to the 4th or 5th gear while driving uphill.

The transmission automatically downshifts to the 3rd or 4th gear so that an optimal engine brake can be achieved while driving downhill.

To prevent unnecessary shifting, this system assesses a winding road condition in accordance with the cornering conditions, in order to achieve optimal shift control at all times.

* Precaution for Dynamic Radar Cruise Control: When there is no vehicle detected ahead on steep downhill slopes, the preset speed will be easily exceeded because of inefficient engine braking. (In this case, automatic braking will not work.) If there is a vehicle detected ahead, the delay in deceleration timing could cause serious injury or death.

jpv7774

Thanks for that educated response......I havent driven my car since I posted the thread but will be very interested to see if it engine brakes if I DONT touch the brakes......thanks for all the info

Timster161

Mine is a 2002 Lexus LS430 and when I go down a hill if shifts from 5th gear to 4th gear but once the hill is over it goes back into 5th is this normal I was just curious please help thank

Johnhav430

It does, thought they all did. Very annoying.

BigBoomer

Mine is a facelift early 2004 and it does not downshift when going downhill unless you tap the brake, at which point it drops to 5th and stays there until it either levels out or ya hit the throttle.
If you don't force it to downshift, the car does gain speed down the hill, even with Cruise Control on.
I usually manually shift to Sport which drops it into 5th and prevents the car from gaining speed when coasting downhill.
If I need more engine braking (steeper hills) I drop it to 4th or lower.
One hill I drive occasionally requires the use of 2nd but then it is a 33% gradient (1-in-3).

Thecar

Oh interesting! I have a 2005. I am going up to the mountains in NC for Christmas, and I will be sure to look out for this on our way down after the holiday!

jpv7774

Yep its true......if u dont hit your brake at all on the top of the hill she will coast pretty fast......if u accidentally tap the brake at the top of the hill during this experiment the car will engine brake the whole way

Thecar

To those who actually want the car to automatically downshift on hills, why not just tip the shifter into a lower gear (or into "L" for the pre-facelift folks)?

You don't have to freely coast if you don't want to.