Auto Idle Stop not working
 

Have had this car for only a week. The auto idle stop worked as it should for about two days. Now the green light never comes on and the idle stop does not kick in when stopped. Pressing the disable button will light the amber warning light on the dash. Now I don't remember if when we first got it if the green light was on all the time (unless manually disabled) or if it only came on when it kicked in? Having driven the vehicle 250 +/- since it last worked I would think after stopping 30 times or so it would have kicked in at least once? Seems like it stopped working totally.

There are several settings that affect the operation of idle stop. Check your manual for more info. Also depends how hard you step on the brakes…light applications might not trigger it.

Thanks, I understand that, this is not the first vehicle we've owned with Idle Stop. My driving technique with the RDX has not changed, same roads, same traffic lights, same speeds. Worked normal for two days but since then It has stopped working for sure. Very strange.

Have you opened the hood with the engine running?
Serious question.

No, I have not.

lMost likely reasons ……..One or more the parameters is not being met and was being met in your previous drives

■ Auto Idle Stop does not activate when:
• The Auto Idle Stop OFF button is pressed.
• The driver’s seat belt is not fastened.
• The engine coolant temperature is low or high.
• The transmission fluid temperature is low or high.
• The vehicle comes to a stop again before the vehicle speed reaches 3 mph (5
km/h) after the engine starts.
• Stopped on a steep incline.
• The transmission is in a position other than (D.
• The engine is started with the hood open.
u Turn off the engine. Close the hood before you restart the engine to activate Auto Idle Stop.
• The battery charge is low.
• The internal temperature of the battery is 14°F (−10°C). or less.
• The climate control system is in use, and the outside temperature is below −4°F
(−20°C) or over 104°F (40°C).
• The climate control system is in use, and the temperature is set to the Hi or Lo.
• is ON (indicator on).
• The dynamic mode is changed to Snow or Sport+ mode.
• The vehicle is stopped by braking suddenly.
• The steering wheel is operated.
• Altitude is high.
• Theclimatecontrolsystemisinuse,andthereisasignific antdifferencebetween the set temperature and the actual interior temperature.
• The climate control system is in use, and humidity in the interior is high.

I would suggest that there is nothing wrong with the auto idle stop, and that the criteria for it to come on aren’t being met. In the unlikely event there is an issue, you’ll be hard pressed to reproduce it for the dealership.

You told @JB in AZ that you had not opened the hood with the engine running, but if you had, it would cause the AIS to stop functioning as you have described.

If this was the cause you would have seen a message on the MID when you came to a stop similar to "Automatic Engine Stop Is Not Available".

Perhaps you opened the hood to show the engine to a friend, or to refill the windshield washer reservoir, etc., and it simply slipped your mind.

Regardless, the procedure to reset the AIS is very simple and I suggest you give it a try, just in case.

I actually used this procedure to disable my AIS, and only re-enabled it today to verify the procedure still works.

Procedure To Disable AIS
With the engine OFF, open the hood, start the car. With the engine running, close the hood. The auto stop function will not activate

Procedure To Enable AIS
With the car already running, OPEN the hood. Turn off the engine. CLOSE the hood. Auto stop now works as it should.

Thank you! I don't currently have an RDX, but I know this was one of the conditions that many miss when they complain about idle stop NOT working.

IF it bothered me, and I had an RDX I might actually do this to disable it.

So I waited a couple of days to see if would keep working..............while out driving around Sunday the auto idle stop kicked in at almost every stop. We changed nothing and my driving habit (I tend to drive slow) did not change. The only change was the weather, Sunday was much colder here in SW Florida. Yesterday and today temps are warmer, yesterday and today the auto idle stop never kicked in. I don't get it?

Not that complex……..weather change, one or more of the parameters is being met now vs prior.

Like…..
Theclimatecontrolsystemisinuse,andthereisasignific antdifferencebetween the set temperature and the actual interior temperature.
• The climate control system is in use, and humidity in the interior is high.

Wait, it only needs to meet one parameter to make it work? The only difference on Sunday the day it worked was it was colder. So we adjusted the temp controls a higher than usual. Hers at 76º and mine at 74º. Everything else was the same I believe. Monday, Tuesday and today it never came on once. Between the 3 days I probably stopped 30+ times. It was not humid on Sunday, in fact the opposite, it was on the dry side.

Is this issue transmissible? I would love to have my AIS stop working.

The parameters in post 6 cause the idle stop to stop working ……….Auto Idle Stop does not activate when:

Also note it’s the humidity inside the vehicle not outside.

Start the engine while the hood is open.

My Auto Idle Stop hasn't worked since my RDX had the intercooler replaced in July of last year (limp mode issues). It's been at the dealership for the last week while they work with AHM to find out why it stopped working after that service visit last year.

Let’s bring back idle stop and why it might stop working.🤯🤯🤯🤯🤯🤯🤯🤯🤯

2021 with 21k miles. No issues…….but idle stopped working. 🤔Nobody complaining, my wife actually said ….don’t miss it.👍. But she did notice it was not working.

Tested the battery with an electronic battery tester after sitting over night 12.4 volts 823 SAE cold cranking passed as 650cca is the standard.
12.4 is slight low for resting voltage.
Trickle charged the battery over night.

Today……..idle stop is back ……..and……..the wife is pissed off.😡😡😡😡😡

Pretty easy to conclude and not a big jump to……..a slightly less than ideal resting battery voltage will stop idle stop. So be carefull what you ask for as other’s are willing to pay $100 for the idle stop stopper device.

Yes……there are several charts and different opinions on resting voltage as % of full charge:


https://cimg6.ibsrv.net/gimg/acurazi...3b7fb68400.png
https://cimg9.ibsrv.net/gimg/acurazi...f8102e862b.png
https://cimg1.ibsrv.net/gimg/acurazi...d2246df8a.jpeg

This was happening with my 2019 RDX and I found I’m out it was when I had the A/C set to “Lo”. I bumped the temperature to 65 and the auto idle kicked back on. Thanks for the info

Sub'd

My AIS has not been working for over a year (see post #8 in this thread),which I was not upset with. I believe that I caused the no-operate condition with the hood open while starting engine procedure listed in the above checklist. Despite trying various combinations of hood being open/closed while staring the engine, the AIS normal operation never returned during that time period.

A few days ago I disconnected the battery for a completely unrelated reason, and when I reconnected the battery, the AIS unfortunately began working again.

If you really want your AIS to function, then taking 5 minutes of your time, and nothing more than a socket or an adjustable wrench, then I suggest you try this method.

Disconnect the battery for several minutes, and then reconnect it. Before doing that you should be aware that it may take several attempts at cranking before the engine will start. In hindsight, the delayed starting may be because I had not given the various computer enough time to fully reboot. You will also find that the estimated distance before empty (fuel tank) will show a very high estimate whenever the tank is refilled. It will take several refills until that estimate returns to a normally expected value. You will also see a message on the infotainment screen that it has been locked. Follow the message on the screen, and push and hold the on/off button for a few seconds to unlock it.

Congratulations

I tried the disable AIS procedure on my 2022 but it didn’t work. AIS was still working.

Yes, I tried that procedure on our 2020 RDX and it didn't work either. If AIS isn't working it's because of something else, most likely not a fully charged battery.

I think you both want a different thing.

@ross7777 is trying to disable AIS from activating, by using the open and close hood method. I'm sure this worked for me a couple of years ago, but failed to work again when I tried more recently. Perhaps a firmware update caused that to change.

@GW208 is trying to get AIS working again. As I mentioned in post #20, AIS had not worked on my 2020 for over a year. Disconnecting, and then reconnecting the battery, has resulted in AIS working normally for the last 2 weeks.

Edit: I can no longer update post #20, but I found an article that may help in the delayed engine start after disconnecting the battery.
Apparently the immobilizer can go into PDI mode (the state the car is in when it is delivered to the dealer) when the battery is disconnected.
To take the car out of PDI mode......

No, I would prefer not to have AIS working.
I tried the hood open, engine start trick back in 2020 sometime and it did work for the first 3 or 4 stoplights where I would have expected the engine to stop. By the 5th stoplight though, AIS was back to activating normally again.

My wife’s 2016 MDX has a menu setting choice to turn AIS off at source. I’ve gotten use to AIS being always on with my 2020 RDX. It’s now 2nd nature for me to turn AIS off when I approach the stop sign at the end of my road.