daryll40

I noticed that if, at a complete stop, you hold down the break pedal hard, the car "holds" similar to the brake hold on my LS460. But only for a few seconds. And there is a light on the dash that comes on during this time. What's going on here? Is this some feature or perhaps something wrong (low brake fluid)?

NateJG

You've discovered the hill hold feature for right-foot brakers. 'Gives one a couple seconds without rolling backward (or forward, for that matter) while the foot leaves the brake pedal for the accelerator pedal.

daryll40

Interesting. Yeah it does that but doesn't work like the hold feature on my LS460 that truly holds the car until you actively hit the gas. This only holds for a few seconds even if you don't hit the gas.

BertL

Correct. IMHO, the RX version is a "first generation", and pretty fiddly for some people including myself to always engage when I want to. Frankly, I find the true HOLD feature I have on my MBZ SLK is superior (maybe like what your LS460 has) -- which uses the electronic brake such that when you easily press further down on the brake after you're stopped, the car indicates on the dash and remains in HOLD until you put your foot on the accelerator. There is no time-out. I find it perfect not only for when I'm stopped on a hill and the light turns green when I don't want to roll back, but say at stop light if you need to quickly reach over to get something from the glove box, or say in stop-and-go traffic where those stops can sometimes be reaaaallllyyyy long.

Droid13

Won't disagree, but just curious. Does the permanent "hold" feature also hold the brake lights on if your foot is not physically on the brake? I could foresee this being a potential safety limitation if "Joe Preoccupied" doesn't notice you're stopped if the brake lights aren't on because you've used this feature

BertL

The manual does not say. I just went out to try and positively confirm, but cannot easily do it by myself. There are too many other safety systems that engage when I try to open the door to confirm while in my driveway. It's daylight here for another couple hours, so trying to jury-rig a mirror on a ladder or something behind my car isn't in the cards right now either to answer your question. ...but I personally am not worried about MBZ design and thoughtfulness in this regard one way or the other. There is nothing to stop say a driver turning off any car while in the middle of stop-and-go traffic which could have the brake lights off (yes, I've seen that at least twice in my years here in SoCal as nutty as THAT was), or say using just a little accelerator to keep your car in position headed uphill while waiting for a light as at least one of my friends many years ago used to do when driving their stick (THAT was scary too!)

While I was researching alternatives for my old SC430 and the 335i that replaced it, I found a number of safety systems we see in other mfgr vehicles today were in fact first developed by MBZ. IMHO, their track record is really good both developing new safety systems and at the same time pushing the envelope with new technology faster and more fully into the market than some of our other favorite brands. (I don't want to take this thread off-topic, so will leave that to your imagination as to more specifics. )

If I get the opportunity some night to try HOLD and can tell if the lights are on in the rear while I'm still sitting in the drivers seat perhaps from a reflection behind me, I'll update this thread. Until then, sorry, don't have a 100% confirmation for you.

vlad_a

Honestly, I am not sure why this feature even exists. I never had any use for it in either the Prius we had prior, or the RX. However, I am very glad it is "on-demand" and does not engage by itself. I have no complaints about it as I never trigger it.
Now, my STi has a more advanced hill hold feature. It actually prevents the car from rolling backwards when stopped. For a noob stick-shift driver, it could be of some benefit. But it is very annoying for anyone that can drive. You just end up stalling the car instead of getting a nice take-off. Luckily, it can be easily disabled, but now there's a solid orange light on the dash that alerts of this feature being off.

Droid13

I've only used it a few times, always in a parking garage on ramps between floors. Last time, went to see NHL game so hundreds of cars slowly making their way out of the garage that had long steep ramps, so frequently having to pause on ramps. The concrete tends to be a bit slippery. Dude 3 cars up driving a standard, every single time to avoid sliding backward on the ramp has to spin the wheels and the squeal echoing everywhere. Got annoying after the 10th time. Me, a quiet beep and a relaxed foot shift.

tqh

In that situation I'd worry more about some idiot letting the car slide back into my car