"Discharge Warning" not staying disabled

Tiny
JEVON DAVIS
  • MEMBER
  • 2020 KIA CERATO
  • 1.6L
  • 2WD
  • AUTOMATIC
  • 28,000 MILES
Disabled the "Discharge Warning" in Engineering Mode but if I come back to my vehicle couple minutes later and start it, the settings revert, and it comes back. How do I make it stay unchanged?
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Friday, May 13th, 2022 AT 7:10 PM

5 Replies

Tiny
STEVE W.
  • EXPERT
Not possible to turn it off without changing the programming in the ECM itself. The most you can do is turn it off and have it come back on restart. It's there because of the way the charging system works on the Kias (and many others) these days. Instead of the older constant charging at a lower amp level like the older cars the newer ones dump a lot of power into the battery soon after initial start-up and if the battery is discharged enough the high amp charge can damage the battery and the charging system.
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Friday, May 13th, 2022 AT 10:03 PM
Tiny
JEVON DAVIS
  • MEMBER
Thank you for the reply Steve, but I am wondering if I have two other colleagues with the Kia and two days have passed and it hasn't come back from them. I am guessing it varies in some instances. Just to add it stays on even while driving, that's my issue. I have gotten the car checked by the Kia Dealership to eliminate issues, but their conclusion is that the sensor is faulty.
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Friday, May 13th, 2022 AT 10:07 PM
Tiny
STEVE W.
  • EXPERT
Okay, if it's staying on while driving that is different than the common reason to turn it off IE; you want to listen to the radio with the engine off. On that system it only can be turned off on some of the earlier firmware versions, others it cannot. As you say it's been a while then that is a different issue.
If it's on while driving it is supposed to mean the battery isn't getting charged as fast as power is being taken from it. In that instance you cannot turn it off because it is detecting a constant fault. Same thing if the oil pump were to fail and turn on the light and shut off the engine, just not as fatal for the engine.
I would start by checking the actual charging system, a quick way for that is to use one of the free tests that some of the parts stores do. If it shows the charging system is okay (which is what I'm thinking the Kia folks found) then you test the sensor itself. First you will want to look as the AMS fuse to be sure it's okay, then check at the sensor for voltage and ground. The sensor reads the amount of power going into the battery and compares that with what the ECM thinks the car is using by using an inductive pickup that is part of the negative cable. It uses the LIN bus to talk to the ECM and determine if the numbers match. It replaces the old standard ammeter. In your case the sensor is sending data that says there is a higher drain on the battery than the alternator is producing. A quick test would be to use a voltmeter. First test the battery voltage with the engine off, a fully charged battery should read about 12.6-12.8 volts. Next start the engine and read the voltage now, if the alternator is charging the voltage should be around 14-15 volts and stay there for a minute then drop back to around 13 volts as it starts to cycle it on and off through the ECM. If you see those numbers the charging system is working, then test the sensors voltage. If those tests good, then the sensor is bad. However, one other item that can fail is the alternators overrun clutch. That isn't something you can test without the factory scan tool; its job is to act similar to the AC clutch and only power the alternator when required.

Replacing the sensor is easy to do. It is part of the ground cable clamp. You simply remove the battery negative clamp, then unplug the sensor, next unbolt the ground cable from the other side (green circled bolt). Reverse the process to install the replacement.
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Saturday, May 14th, 2022 AT 1:27 PM
Tiny
JEVON DAVIS
  • MEMBER
Thanks Steve, very useful information. I would like to add to that question. I realize there are entry level Kia Cerato 2020 that has this radio that I have attached. One or two people I know changed out the radio to the 8" touch screen and have the same battery issue. Is it because the entry level/lower spec may not have come with the sensor? Just to add to this it seems the connections are different so for e.G. It doesn't have the antenna connection so they can't set the time, but they go into engineering mode and edit the clock settings and of course it doesn't keep the settings once the car restarts. So in these two cases would maybe not having the sensor in the car originally be the problem? Also, would not having the antenna connection be a contributing factor to the clock settings?
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Saturday, May 14th, 2022 AT 4:13 PM
Tiny
STEVE W.
  • EXPERT
They still would have the sensor, but it likely only activates a warning light as the lower-level stereos don't use the LIN network. Antenna shouldn't do anything to the clock. The likely reason for it to lose settings would be where it gets the power feed to the memory in the radio and where it stores that info. About the only way to know for sure would be to map out the wiring to both units and see what is different, and what options are locked out through programming. For instance you can add fog lights to many vehicles that had them as an option, plug in all factory parts and they still will not work because the option code for fog lights isn't in the control module, because you didn't pay the extra for it. Could be a similar thing as well as the connections. With the modern rolling computers things like this are common.
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Sunday, May 15th, 2022 AT 2:04 PM

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