[E92Vancouver]

2016 SH-AWD Advance/Entertainment

I bought this car last Thurs and every time I stop, this message pops up "Automatic Engine Idle Stop Unavailable". I made sure to press the button to enable it I even tried to drive no heat, no radio, no nav, etc but it's still not kicking in. I heard it sometimes doesn't work when it's really cold. But the other day when I drove it, it was above 40F. Any suggestion? I've scheduled to take it to the dealer next week.

I have auto start stop. It won't work for months and then all of a sudden it works all the time (almost too much) and then it stops working for months. If your battery charge is too low (i.e you do a lot of short trips) the computer will keep your engine running at intersections to charge the battery. Take a 6 hour highway trip which will charge your battery and get your auto start stop working. Long highway trips always bring my start stop back to life again.

 

[PTC DAWG]

This “feature” not working seems like a bonus...

 

[TheDoug]

This ?feature? not working seems like a bonus...

I absolutely agree with you. I wish I could get mine to turn off permanently

 

[Nattie1974]

Hum, we just bought a 2017 MDX 2 weeks ago (2 years old, was in the showroom all that time with a dead battery when we looked at it) and this on/off auto engine worked for 3-4 days and now it won't work anymore. I didn't like the feature so it doesn't bother me but we just did a long trip (over 6 hours in 2 days) and its still off. The a/c is on in the car so maybe that's it? I wish this feature would work when its supposed to. Whats the point of having it otherwise?

 

[FastForward]

I bought the 2020 AWD MDX last week. Despite turning off everything from radio to heater/AC and driving in 65 degree sunny daytime, the Automatic Engine Shut-Off fails to work. It just says its "unavailable". The dealer says its normal for it not to engage due to some mysterious undefined reason. So this added $300 to the sticker price and it does nothing?

 

[EbonyGraph]

I had the same question after I recently purchased my 2016 CPO ADV. Dealership told me that is probably because of the car sitting in the lot for few weeks and will fix itself once I start driving it regularly.
Though it took couple of days, Auto Idle Stop feature started to work.
Apparently, a number of factors determine to enable idle stop or not for safety reasons. Obviously you don't want idle stop to trigger if the battery is not fully charged, right?

 

[FastForward]

I had the same question after I recently purchased my 2016 CPO ADV. Dealership told me that is probably because of the car sitting in the lot for few weeks and will fix itself once I start driving it regularly.
Though it took couple of days, Auto Idle Stop feature started to work.
Apparently, a number of factors determine to enable idle stop or not for safety reasons. Obviously you don't want idle stop to trigger if the battery is not fully charged, right?

Thank your for your reply. I suspected just that. I'll drop by the dealer service to let them check the battery and recharge if necessary. Frankly, I don't really care for the feature but I have learned that if something is not working, it may be something deeper that is a problem than just that feature.

 

[mrdeeno]

I’ve had this issue on and off since I picked up my ‘17 Advance last month. After reading through all the things that make it “unavailable”, if you have eliminated those factors the last thing to try is the hood open reset I found here on the Odyssey forums:

Copy/pasta from https://www.odyclub.com/threads/auto-idle-stop-potential-fix-procedure.337977/

Procedure to try fix AIS:

1. Take your van out for at least a 15 min trip and be sure it’s warmed up. If you have the message popup activated, confirm that is says unavailable when you come to a stop.
2. Park somewhere safe, shutoff the van. Open the door and pop the hood.
3. Get out and open it up and prop it up on the kickstand.
4. Get back to the seat, start the car, close the door, confirm the message center says hood open.
5. I got out the van, looked at engine and then went back and shut it off. I think I left the door open and leaned in to turn off, and then returned to shut the hood. (not sure if door open/close played a role yet)
6. Get in, close the door and start normally.
7. Take it out for a drive, and AIS should work instantly, assuming all conditions are met.

I’ve had my car to the dealer for some CPO work for other issues, and whenever I get the car back the “unavailable” thing occurs even when all the other factors are satisfied, and the steps above always seemed to fix it right away.

 

[elvisfan]

I bought the 2020 AWD MDX last week. Despite turning off everything from radio to heater/AC and driving in 65 degree sunny daytime, the Automatic Engine Shut-Off fails to work. It just says its "unavailable". The dealer says its normal for it not to engage due to some mysterious undefined reason. So this added $300 to the sticker price and it does nothing?

How do you figure it added $300 to the sticker?

 

[FastForward]

I’ve had this issue on and off since I picked up my ‘17 Advance last month. After reading through all the things that make it “unavailable”, if you have eliminated those factors the last thing to try is the hood open reset I found here on the Odyssey forums:

Copy/pasta from Auto Idle stop potential fix procedure


I’ve had my car to the dealer for some CPO work for other issues, and whenever I get the car back the “unavailable” thing occurs even when all the other factors are satisfied, and the steps above always seemed to fix it right away.

Do you have to do this every time you get in the car?

 

[FastForward]

How do you figure it added $300 to the sticker?

That is what it costs if you want to add it as an option to a car where it is not standard equipment, so I was told.

 

[elvisfan]

That is what it costs if you want to add it as an option to a car where it is not standard equipment, so I was told.

Ok, it’s standard on almost every car now. I can’t imagine anyone actually adding it. Besides that, components have to be reinforced. I don’t think it could be added.

 

[digibrain]

hi guys,

i'm actually the guy from the other thread, who bought a HDS to diagnose the auto engine idle stop problem on the MDX. having it always not working and just showing "unavailable". i had to get down to the bottom of it without the help of the dealerships.

what i really found out with the HDS, is that the triggering factor (of it not working and showing "unavailable") was with the BMS (battery management system) which checks only 2 things (according to HDS info): 1. battery temperature and 2. state of charge. i checked the battery temperature from the hds reading/parameter and is at 27-28C (and i ran it a 2nd time, battery temp was at 37C) which is in normal range, but "idle stop inhibit (BMS)" is still red, so that means the auto start/stop feature isn't working because of "battery state of charge" reason. meaning the bms module does think that the battery is not fully charged. especially if there was a lot of drain on the battery while the engine was off for a long time (e.g. #1 if the idle stop was activated until the battery drained to the point that the engine restarted by itself before you got to a green light, #2 if the car was parked for a long time ("park&fly" sort of thing)with something draining the battery down) then the BmS module would think there isn't enough stored charge on the battery so it gives you "unavailable" on the dash when you come to a complete stop.

also, the alternator on these mdx's (2016 & up) are always (for most of the time) running in their "Low power output" unless you turn on (i forgot if full headlights on or full headlights on + fog lights) triggers the "high output charge" on the alternator. they somehow output just around 12.3v while you are driving with the low output mode. (i guess fuel efficiency design for honda/acura to achieve more mpg). less drag for the alternator on the engine when operating in the low power output. so the battery doesn't get charged up to the point the BmS would allow it to go to Idle stop mode. hence the "unavailable" message on the dash. charging a low charge battery at 12.3v doesn't really get it charged up quickly even if it is an AGM battery. it needs more voltage & current to get a depleted battery up quickly. high output mode usually in the mdx is around 14.something volts. and does replenish the charge between traffic light stops...


what i have done, is i have left the headlight switch on "ON" all the time + the fog lights "on" and it always triggers the high output mode of the alternator. the down side is driving with your full low beams on even in the daytime. also don't worry leaving your headlight switch to the "on" position, as when you get off the mdx (it will chime to remind you the switch is still "on") and park it, the bms module will shut the headlights off after 1 minute of locking the doors.

after leaving the headlight switch on the "on" position all the time (24/7), the idle stop always works 100% of the time.

i even went the length of plugging in the battery when i get home to a smart charger just to make sure in the morning when i wake up, the AGM battery is fully topped off. but you don't have to go that route. too overkill in my opinion.



so the short solution to this "unavailable" problem is to keep your headlight switch on the ON position i guess.


so let us know if that works for you,
we'd like to hear feedback

thanks,
hope this info helps

jeffrey

I, too, am trying to get to the bottom of this issue with the auto engine idle stop (AEIS) feature. On my 2018 MDX, I recently discovered that resetting the codes with an OBD reader, even if there are no outstanding codes, causes the charging system to re-initialize and the AEIS to start working after a couple of driving cycles. Even if the temperature outside is cold, it still works. In my case, after a couple of weeks, the AEIS gradually stops. I'm saying gradually because it starts by taking longer and longer to kick in after a cold start and eventually it stops working completely until a new code reset is done. I noticed also how the charging system appears to test the charging capacity of the battery, especially after resetting the codes. This is noticeable by plotting the battery voltage vs. time in a drive cycle. My OBD reader can gather CSV data and I can then plot it. The voltage drops to around 12V at some given intervals, every 2-3 min or so, then goes back to charging (around 13.8V) After some days, this testing becomes more sporadic and the charging is continuous (voltage stays at 13.8V). And then, for some reason, the AEIS feature stops working. I am still trying to understand this reason. Also, I should mention that instead of resetting the codes with an OBD reader, one can simply disconnect and re-connect the battery, which causes a similar reset to the codes (the ECU parameter called "distance since last reset" goes to zero) The battery in this MDX is a new AGM made by Energizer and it is specified for this car. I am not discarding that the battery is faulty even though it's new. The problem was the same with the previous battery, which was the original one.

 

[Trident]

Last week we had a ECM firmware update that was for a recall notice from Acura.

 

[digibrain]

Last week we had a ECM firmware update that was for a recall notice from Acura.

I had the transmission firmware update (recall campaign M21/M22) done early last month. It didn't have any effect on the auto engine idle stop feature.

 

[hoffman.kevin]

I had the Auto Stop Update done by Acura (TSB23-001/002) which changed the Idle Stop operating range. Since then the Auto Stop quit working. I took it back to the dealer and they said I needed a new battery (almost $400). My MDX is a 2017 and the battery was replaced in 2019. The car starts fine and when started with the lights on, they don't dim at all. The TSB does state that after the idle stop update, there may be reduced idle stop engagement when the battery is approaching the end of its useful life.

 

[2020MDXLover]

I too am experiencing this issue. I got a gem of. 2020 with the technology package with only 13,000 miles!! Everything works but the auto stop. The car has been sitting in the dealer lot, tons of on/offs and playing with the accessories. Last night alone I was tweaking my android auto with just the accessory on. My guess is mines not working because of "lower" voltage. I tested the resting voltage and I'm at about 12.5-12.6. I put it on a battery maintainer and we'll see if the auto stop comes on after the battery has fully come up to charge.

Funny enough, when we got the car home I told my wife to always turn it off when she's driving as I'd rather not have the wear and tear on the starter. But it's a feature that should work so I'll keep and eye on it and take it to the dealer if it continues.

Here's the beauty I picked up. My first ever Acura as well!!