Beware of "brake hold" + warm up bug
11-26-2018, 09:09 PM
#1
Beware of "brake hold" + warm up bug
I just encounter this "brake hold" bug this past weekend. I have been using brake hold on and off for months and this is the first time that this happened. Here's the scenario.
I went out of town this past weekend. This is the first time that the rdx was parking outside overnight in the cold (around 35F / 1-3C). So I started to drive for the first time that day. I drove for about approx 10 min, then I wanted to check something on my phone, so I pulled over to the side of the road. When I came to a complete stop, the auto start/stop kicked in and turn off the engine. That was the first time it kicked in during that drive. Not wanting to restart the engine (by putting it in park / turning on parking brakes), I turned on brake hold. The "hold" is green, so i let go off my foot.
After 5 - 10 min or so, the engine restarted. However, that caused my brake hold to disengage and my car started to roll forward. Luckily, there wasn't anything in front of me but it did roll forward by 3 feet.
My guess is that the engine temperature wasn't high enough ( or the engine temp dropped while standing still) and restarted the engine. The "warm up" logic in the engine must have added some gas (eg higher rpm) and canceled the hold.
Beware of brake hold when the engine is not fully warmed yet.
I went out of town this past weekend. This is the first time that the rdx was parking outside overnight in the cold (around 35F / 1-3C). So I started to drive for the first time that day. I drove for about approx 10 min, then I wanted to check something on my phone, so I pulled over to the side of the road. When I came to a complete stop, the auto start/stop kicked in and turn off the engine. That was the first time it kicked in during that drive. Not wanting to restart the engine (by putting it in park / turning on parking brakes), I turned on brake hold. The "hold" is green, so i let go off my foot.
After 5 - 10 min or so, the engine restarted. However, that caused my brake hold to disengage and my car started to roll forward. Luckily, there wasn't anything in front of me but it did roll forward by 3 feet.
My guess is that the engine temperature wasn't high enough ( or the engine temp dropped while standing still) and restarted the engine. The "warm up" logic in the engine must have added some gas (eg higher rpm) and canceled the hold.
Beware of brake hold when the engine is not fully warmed yet.
11-26-2018, 09:36 PM
#2
Senior Moderator
Forgive my ignorance but why couldn't you put it in Park without turning off the engine..?
11-26-2018, 09:48 PM
#3
It is not that I couldn't turn off (completely) the engine. It's that I don't want to restart the engine while the auto start/stop system already stopped the engine.
See https://acurazine.com/forums/third-generation-rdx-2019-454/autostartstop-turns-engine-when-you-shift-park-971979/
See https://acurazine.com/forums/third-generation-rdx-2019-454/autostartstop-turns-engine-when-you-shift-park-971979/
11-26-2018, 10:21 PM
#4
I just encounter this "brake hold" bug this past weekend. I have been using brake hold on and off for months and this is the first time that this happened. Here's the scenario.
I went out of town this past weekend. This is the first time that the rdx was parking outside overnight in the cold (around 35F / 1-3C). So I started to drive for the first time that day. I drove for about approx 10 min, then I wanted to check something on my phone, so I pulled over to the side of the road. When I came to a complete stop, the auto start/stop kicked in and turn off the engine. That was the first time it kicked in during that drive. Not wanting to restart the engine (by putting it in park / turning on parking brakes), I turned on brake hold. The "hold" is green, so i let go off my foot.
After 5 - 10 min or so, the engine restarted. However, that caused my brake hold to disengage and my car started to roll forward. Luckily, there wasn't anything in front of me but it did roll forward by 3 feet.
My guess is that the engine temperature wasn't high enough ( or the engine temp dropped while standing still) and restarted the engine. The "warm up" logic in the engine must have added some gas (eg higher rpm) and canceled the hold.
Beware of brake hold when the engine is not fully warmed yet.
I went out of town this past weekend. This is the first time that the rdx was parking outside overnight in the cold (around 35F / 1-3C). So I started to drive for the first time that day. I drove for about approx 10 min, then I wanted to check something on my phone, so I pulled over to the side of the road. When I came to a complete stop, the auto start/stop kicked in and turn off the engine. That was the first time it kicked in during that drive. Not wanting to restart the engine (by putting it in park / turning on parking brakes), I turned on brake hold. The "hold" is green, so i let go off my foot.
After 5 - 10 min or so, the engine restarted. However, that caused my brake hold to disengage and my car started to roll forward. Luckily, there wasn't anything in front of me but it did roll forward by 3 feet.
My guess is that the engine temperature wasn't high enough ( or the engine temp dropped while standing still) and restarted the engine. The "warm up" logic in the engine must have added some gas (eg higher rpm) and canceled the hold.
Beware of brake hold when the engine is not fully warmed yet.
11-26-2018, 10:26 PM
#5
I don't know how long, but I have brake hold longer before during the summer. As far as i remember, the default turn off brake hold behavior should be shift to park instead of rolling forward.
11-26-2018, 11:21 PM
#7
It was probably close to 5 mins then 10 mins.
Here's page 292 of the manual:
■ The system automatically cancels and the parking brake is applied when:
• Braking is kept for more than 10 minutes.
• The driver’s seat belt is unfastened.
• The engine is turned off.
• Brake Hold System Problem. Apply Brake When Stopped. See Your Dealer. appears on the multi-information display.
• There is a problem with automatic brake hold system
The manual specified which conditions the brake hold will be cancel, but didn't specified which action it would take. However, I can tell you for certain that "driver's seat belt is unfastened" and "engine is turn off" will NOT result in car rolling forward. If you unfasten your seat belt, it will shift to park. Regardless of whether it's 10 minutes or not, if the brake hold function cancels (not due to gas pedal or manually turning it off), it should shift to park instead of rolling forward. That seems dangerous.
Here's page 292 of the manual:
■ The system automatically cancels and the parking brake is applied when:
• Braking is kept for more than 10 minutes.
• The driver’s seat belt is unfastened.
• The engine is turned off.
• Brake Hold System Problem. Apply Brake When Stopped. See Your Dealer. appears on the multi-information display.
• There is a problem with automatic brake hold system
The manual specified which conditions the brake hold will be cancel, but didn't specified which action it would take. However, I can tell you for certain that "driver's seat belt is unfastened" and "engine is turn off" will NOT result in car rolling forward. If you unfasten your seat belt, it will shift to park. Regardless of whether it's 10 minutes or not, if the brake hold function cancels (not due to gas pedal or manually turning it off), it should shift to park instead of rolling forward. That seems dangerous.
Trending Topics
11-26-2018, 11:27 PM
#8
Just re-read the manual carefully, it states
■ The system automatically cancels *and the parking brake is applied* when:
• Braking is kept for more than 10 minutes.
so, it was something else that cancelled the brake hold and cause the car to roll forward. I suspect, it's the engine restart due to Auto start/stop conditions.
■ The system automatically cancels *and the parking brake is applied* when:
• Braking is kept for more than 10 minutes.
so, it was something else that cancelled the brake hold and cause the car to roll forward. I suspect, it's the engine restart due to Auto start/stop conditions.
11-27-2018, 09:29 AM
#9
Burning Brakes
I have had this issue also, I was a Coffee drive thru getting my food, the brake hold was on and the engine turned off from auto stop. It then restarted and my brake hold cancelled right as I was about to grab the drink they were passing me, scared the crap out of me, I have had this happen a few other times as well, definitely under 5 minutes for when it happened to me, as little as a couple mins
11-27-2018, 10:20 AM
#10
Thanks for the warning. This will cost someone some $$ at some point.
I've messed with brake hold a little here and there, but I must be missing something. I don't get what the point is. Holding the brake is no effort and putting a vehicle in park is even less. Not trying to be sarcastic. I just don't get it. Anyone have a good practical example of it's use.
I've messed with brake hold a little here and there, but I must be missing something. I don't get what the point is. Holding the brake is no effort and putting a vehicle in park is even less. Not trying to be sarcastic. I just don't get it. Anyone have a good practical example of it's use.
11-27-2018, 12:32 PM
#11
I had a similar thing happen to me the other day. I was using brake hold in an area with a lot of stop lights. I stopped at a red light, the engine shut off and the brake hold engaged. Within seconds, the engine restarted and the brake released just as a pedestrian was crossing in front of me. Fortunately I reacted in time, but it was a scare.
11-27-2018, 12:54 PM
#12
Drifting
Join Date: Apr 2018
Location: New Yorkie, Hudson Valley
Posts: 3,001
Received 1,025 Likes
on
715 Posts
Thanks for the warning. This will cost someone some $$ at some point.
I've messed with brake hold a little here and there, but I must be missing something. I don't get what the point is. Holding the brake is no effort and putting a vehicle in park is even less. Not trying to be sarcastic. I just don't get it. Anyone have a good practical example of it's use.
I've messed with brake hold a little here and there, but I must be missing something. I don't get what the point is. Holding the brake is no effort and putting a vehicle in park is even less. Not trying to be sarcastic. I just don't get it. Anyone have a good practical example of it's use.
Other than that, I think it is more trouble than it is worth.
11-27-2018, 06:21 PM
#14
The brake hold will always disengage for me when the auto start/stop restarts the car. Scenario: Auto start/stop is turned on and I also have the auto brake hold on. I stop at a light etc and push the brake enough to enable the brake hold & the auto S/S shuts the car off. The times that the car started itself before I hit the gas the restart also disables the brake hold and the car starts moving forward. I’m not sure if it was designed to behave this way or not but that has happened to me several times now.
11-27-2018, 07:16 PM
#15
I had a 2015 TLX and used brake hold every day. I never once had the brake hold release when the engine restarted. I have had it happen twice in the past week in my RDX. This is definitely not normal. I will mention it to my dealer when I go in for my first service.
I think that both times when it happened I had pressed the Auto Start/Stop button to restart the engine. I'll pay attention from now on to see if it happens when I wiggle the steering wheel or only when I press the button.
I think that both times when it happened I had pressed the Auto Start/Stop button to restart the engine. I'll pay attention from now on to see if it happens when I wiggle the steering wheel or only when I press the button.
Last edited by Syzygy; 11-27-2018 at 07:19 PM.
11-27-2018, 08:32 PM
#16
Billy
11-30-2018, 05:13 AM
#17
I have had this happen once too. Similar scenario, but it wasn’t very cold outside and the car had only been sitting about an hour prior. Came to a stop light, brake hold engaged and auto S/S turned the engine off. Sat there for a minute (I need to read the manual, but I don’t think auto s/s goes longer than a minute at a time..) anyhow, car started back up on its own and was almost like there was too much power for the brake hold to properly keep the car from moving forward. Had to intervene.
This is my wife’s car and she never uses brake hold, and I rarely drive it and rarely use brake hold, hence the only one occurrence.
This is my wife’s car and she never uses brake hold, and I rarely drive it and rarely use brake hold, hence the only one occurrence.
11-30-2018, 08:23 PM
#19
I don't get this dismissive altitude. The main point of this thread is not to complain about the car. It's to warn other owners of this buggy feature, so that they won't crash into something or god forbid, someone.
It's perfectly reaonable to use brake hold in short stop scenario (such as drive thru and red lights). And I would argue that this feature is actually designed for it.
For you to say "Next time, just hit the ignition button. Problem solved." -- it's like me saying just turn your head and look thru the rear window when you are saying that the rear view camera is not working.
It's perfectly reaonable to use brake hold in short stop scenario (such as drive thru and red lights). And I would argue that this feature is actually designed for it.
For you to say "Next time, just hit the ignition button. Problem solved." -- it's like me saying just turn your head and look thru the rear window when you are saying that the rear view camera is not working.
11-30-2018, 08:29 PM
#20
Instead of putting it in park and then turning on the parking brake, just turn the car off. The car goes automatically to park and then you can turn the parking brake on. In fact, I normally put the parking brake on and then turn the car off. I don't know that I have ever hit the park button.
Billy
Billy
Not sure if you know this, you can even set the car to turn on parking brakes automatically after ignition have been turn off. You don't need to do it manually. Look in the manual or other threads in the forums for instructions.
11-30-2018, 09:59 PM
#21
Billy, the point here is to keep the car ON (eg. Climate control , seat warmers etc) for a temporary stop.
Not sure if you know this, you can even set the car to turn on parking brakes automatically after ignition have been turn off. You don't need to do it manually. Look in the manual or other threads in the forums for instructions.
Not sure if you know this, you can even set the car to turn on parking brakes automatically after ignition have been turn off. You don't need to do it manually. Look in the manual or other threads in the forums for instructions.
Billy
Thread
Thread Starter
Forum
Replies
Last Post