Hyundai Santa Fe Forums banner

2019 Santa Fe Auto Engine Stop-Start

64K views 35 replies 23 participants last post by  dsc1964 
Hi, newbie here. I'm not good at forums so hopefully I don't offend anyone. I will start by saying I am NOT a Hyundai guy, but since we do have one in the driveway, I led me here.

I basically joined this forum specifically because I want to know how to permanently disable the ISG. I read that one member says to stick a toothpick in the button to hold it down. I want to go one better... has anyone just simply bypassed the switch by connecting the switches hot and grnd wires together, and if so, did it work?

Please let me know. Thanks
You can bypass or automatically default the ISG to "inactive" a few seconds after starting the vehicle.

Go to Post 11 in this thread. https://www.santafeforums.com/isg-idle-stop-go-also-known-auto-stop-t14269.html It will take you to another forum, where this is documented in detail. Read it, and if you still have questions, message me and I'm sure we can find a solution you can work with. The other forum will give some specific details on a way to default it to OFF but can be done with many variations of what is posted in the details.

To make it simple, here is what is in the other thread, post 11:
Just FYI... there are some ways to default ISG to OFF (inactive). Some methods are more involved than others. I've documented some of these in another forum. Of course, you can review and see if any method appeals to you and your needs. Hope you find what you need.

Since the Forum will not allow me to post the entire URL here, you will have to put all these pieces together to "build" the URL. (take out the spaces in the line below to create the full URL)


https:// www. hyundai-forums .com/threads/ options-to-manage-the-isg-idle-stop-and-go-function.658336/#post-5936672


Every time I start my car, it automatically defaults the ISG to OFF. I built a custom wire harness so it is plug-n-play and no splicing of wires. However, the same can be accomplished by splicing wires. And can be done for as little as $30. By the way, I would not recommend just wiring the hot (ISG control) and ground together as the original switch has a resistor in it (200ohm). The ISG control wire is from the ECM (main engine computer). Review the documented information in the other forum and contact me if you have questions or want to discuss it in more detail.
 
I seem to have a different issue than most. I don't mind the ISG (Idle Stop and Go) and have adjusted to it. But recently it has failed to activate. First time I took it to the dealer, they replaced the sensor. That worked for maybe a week or two. Next time at dealer they said battery was not properly charged. Since they could charge the battery to a satisfactory level and checked the alternator, they could not replace anything. Not long after that it failed again.

As to the alternator properly charging, I am curious. My dealer is 45 miles away, mostly highway miles. You would think that could charge a battery. And yet when I drive more than 100 miles, as on a recent long trip, ISG started working again.

Something that may deplete the battery is my volunteer work. I deliver Meals On Wheels so I have made a lot of stops within an hour; maybe 6 to 12.

Being a retired engineer from a chemical plant, I miss these tricky types of problems to solve. I'm almost enjoying the challenge. You can call me "Sheldon" ;)

FYI attached is the Tech Service Bulletin issued March 2019 that refers to the ISG operation and battery issue. Interesting that this exists, isn't it!?!

UPDATE: Dealer will replace my battery free of charge in an effort to correct this issue. Stay tuned.
Lots of information to digest. So many things in play for ISG to activate. Like so many others, I'd guess your battery State Of Charge (SOC) is below the threshold for ISG to activate. This is not unusual. These newer vehicles do NOT constantly charge the battery like older vehicles do. Instead, in an attempt to save a bit more fuel, they are designed to charge when it does not detract from fuel mileage. Often, that is under deceleration, etc. They are designed to keep the battery charged enough to reliably start the car, but may not keep the SOC high enough for the ISC to activate. This is especially true for those who drive short distances. Hyundai is not the only manufacturer where this is obvious (the Ford F150 is also notorious for this same situation). If you really like the ISG, I might suggest getting a battery tender which you can plug in every night while at home. Since my vehicle is not driven on a regular basis, I've used the battery tender and wired it to the ground & + post on the battery, and hung the lead out the front of the grill so I can easily plug it in whenever I want to (make sure the - is connected to a ground, not the negative battery post - this way the vehicle can still monitor the state of the battery). Try this and I'll bet your ISG activates on a regular basis. Anyway, I cannot prove what I've stated so assume it is just my opinion. For less than $20, you can get a small battery Tender at Harbor Freight and see if it fixes your issue. Those who get the battery replaced, will likely see the same issue return over time. Anyway, good luck and hope you get it working the way you expect.
 
My 2019 Santa Fe intermittently won't start. The first 5 times it stopped at a red light on a 45 and 50 MPH road in the left lane. It would not restart on its own and would not restart when i pushed the start button in drive nor park nor neutral. Pushing the override switch did not help. turning the car off via the push button did not help. What might have helped the first time was turning the ignition off, then letting the timers time out (lights etc and then opening the door to turn off the delayed accessory buss. After 10 or 15 minutes with traffic flying by me at 55 mph, it finally restarted. Second time it took 5 minutes, third time it restarted by putting into park and cycling the push button start several times.

By now we are good at using the override immediately so it has not stopped at a traffic light ever.

But now we have had 2 occurrences of the engine not starting in the morning after sitting all night and during the day after an 18 hole round of golf (5 hours?). It always has restarted after multiple attempts.

I took it to the dealer and they said they would diagnose it and see if there were any codes and then let me know if they needed to keep the car to fix it and if so would give me a free rental car. So I made an appointment. They have 2 techs and two scanners and finally scanned it after 45 minutes and then it sat outside. After almost 2 hours, i was told there were no codes and they wanted to keep it overnight or till they fixed it, but had no rental cars. In addition, they didn't have technicians to look at it anymore, my 30 minute window was over. They didn't know when a tech would look at itm cause they had appointments all the time and also 7 blown engines to fix (reason for no rental car).

I asked if they could hook up a scanner and i would sit outside and continuously start the car to repeat it. They don't have a third scanner so no. I have no idea what they would do if I left the car there, but only having one car, I had to take it.

Being a retired GM diagnostic engineer, I suggested that they just replace all the possible parts (relays, starter solenoid, switches or whatever) that could fix the problem since this is a definite safety problem and they should not be sending me home with a car with a serious safety problem. She said there was no way they could know what to fix without a code. I said you don't have any trouble trees that don't start with a code? They don't. Besides Hyundai does not let them fix a part without a code. So they need a code but have no way to have anyone try to reproduce it to create a code with a scanner on. Apparently, part codes go away and are not always stored in history. I explained how a good dealer will replace all of the parts that might be causing the problem so as to not make the customer come back several times before they pick the right part...and a bad dealer will replace one at a time and piss off the customer when he has to come back 2, 3, 4, 5 times to get his car fixed. Well, Hyundai makes you come back many times infinity) and never replaces any part...so I can imagine this going on till the part totally fails and strands me, if I am lucky, or until someone rear ends me at 55 MPH.

It sounds like there have been several of these in previous comments here. Has anyone set a code that I can tell them to use? Has anyone had a certain part replaced? Or other fix?
I've not seen an update to your issue. What you have going on is NOT normal. Hopefully the dealer has found and resolved the issue. There are many factors which affect the ISG function so it can be difficult to determine which one is the culprit. Based on your description, I don't think the ISG is the issue, rather just the ability to reliably start your vehicle. Has your problem been resolved?

I know this won't solve your issue of starting, but there is a way to default the ISG to OFF with a bit of effort. I've documented this in another forum. While I explain how to create a plug and play solution (with connectors to match the vehicle), one could just tap into the existing wiring harness and at least stop the ISG from activating. This solution does not disable ISG, it simply turns it OFF just after starting the vehicle (simulates the user pressing the ISG button). ISG can be turned back on (by pressing the ISG button), and ISG feature remains functional should you want to use it. One can default it to OFF for about $30 (if you tap into the existing wires). Take a look if you are still having issues, and PM me if you have specific questions about disabling the ISG. By the way, since this forum will not let me post the other forum's web page, the full URL is below but I've added spaces (you will need to remove the spaces in order for the web site to bring up the page).
https:// www. hyundai-forums .com/threads/ options-to-manage-the-isg-idle-stop-and-go-function.658336/#post-5936672
Hope this helps and hope you have a solution. Good luck!
 
Update as requested.

It took several weeks, but the USA Hyundai service got involved and gave them tests to run and it ended up needing a new Starter motor assembly. Everything has worked fine since then.
I'm glad they found the issue and were able to resolve it. Some of these issues can be a challenge to determine the exact cause. The no start issue kind of left you in a hazardous situation. Thanks for the update.
 
Top