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My OEM battery died a couple of days ago, so I got a new one at Advance Auto. I've read that the BMS resets itself if the car is left alone for 8+ hours, which mine has been for the last two nights. Can I assume that the BMS was automatically reset? Car starts/runs fine. No warning lights on the dash.

Is there any indication that it wasn't reset, like the batt light coming on?
 

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no.

if yours has the BMS, not positive all of them do, then it will need to be reset.

same thing happened here 3 months ago. OE battery bit the dust, put new battery in and sometimes it would say battery there was low battery if I had the key on engine off, even after sitting over a weekend and checking the battery. i realize this may not be happening to you, but it doesn't reset itself.

reset it with forscan, and immediately the radio seemed louder at a lower volume and I noticed my key fob works fast again like it hasn't in forever, and security light and lock light actually stay activated for longer again after the car is parked and locked.

definitely not placebo. my radio come on loud as hell automatically as soon as it reset and the locks locked and I think it honked the horn.
 

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#dailydriven
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that's odd. i've had my battery out for various reasons multiple times and i've never once had any issues when i put the battery back in the car.
 

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me either. never got a warning for low battery before the OE battery died and wouldn't recharge--6 years old BTW.

after driving on a brand new battery for a week, letting it sit for 24+ hours, I noticed if I just left the key on a few moments before cranking it would warn for low battery. tested new battery, fully charged before testing, and put it back in, same stuff.

I know it doesn't reset itself though. after resetting BMS it hasn't happened and the one thing that was pissing me off for like the previous 6 months or so was the key fob not being as responsive even after it got a new battery. slightest touch it works now immediately
 

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#dailydriven
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Do these issues only happen if you change the battery? I've had mine completely disconnected and out of the car multiple times and put back in and never had a light or had anything act weird.
 

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have no idea.

I attributed mine to the battery going completely dead like so dead it wouldn't jump.

I think it sets a flag in the bcm.

from what I've read the BMS monitors current and uses a formula in the bcm to calculate battery life and health and uses this formula to cut power as it sees appropriate to accessory powered devices to preserve a stabilized current.

I say if you replace the battery or it goes completely dead, it needs to be reset cause it can't reset itself.

I know of at least one instance where a bad battery killed a TCM in a focus and we at work had it all fixed for free from ford. battery went dead and the car kept acting like it was shifting into neutral after being unused off and in park, and without any user interaction. it was like it was possessed. ford said battery dying, being jumped off, and the car being driven with a weak battery fried the TCM. all fixed under warranty and they weren't surprised and seemed to act like it was common.
 

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#dailydriven
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well damn. how do you reset the BMS?
 

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well damn. how do you reset the BMS?
forscan, under services tab. you might have to have the extended license, but that's fast and free, just have to register and be approved at the forum and then ask for a code. takes up to a day.

if you do it, verify if the horn honks or not. I really can't remember.
 

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#dailydriven
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sorry, i guess i'm a newb, but what is Forscan?
 

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My OEM battery died a couple of days ago, so I got a new one at Advance Auto. I've read that the BMS resets itself if the car is left alone for 8+ hours, which mine has been for the last two nights. Can I assume that the BMS was automatically reset? Car starts/runs fine. No warning lights on the dash.

Is there any indication that it wasn't reset, like the batt light coming on?
This is correct.

Hello from Germany
My English is not so good. My german is much better. [wave]

You can not actually recognize from the outside whether BMS is reset.

Important is that you have a battery of the same type and performance installed. If an EFB battery was previously installed, an EFB (Enhanced Flooded Battery) must be installed again. Never install a lead acid battery.
Alternatively you can use a AGM battery.
If you have a battery sensor on negative pole, you have a smart charge charging system. (Intteligent load system)
This smart charge charging system charges with 14.8 volts load voltage. Lead acid batteries are charged with 14.6 volts.
The smart charge charging system from the ford focus mk3 (with Start/Stop system) overcharge a lead acid battery. Battery is broken in a short time.

Look at your car battery negative pole. Do you have a BMS (Battery Monitor Sensor)?
Only cars (Ford) with Start/Stop System have a EFB battery (Enhanced Flooded Battery) and a BMS.
All others (old Ford's) have normal lead-acid batteries in it. Lead batteries do not have a BMS.

For a reset of the BMS:
1. Switch on ignition (do not start engine)
2. Switch on dipped beam
3. Press 5x the rear fog light button (do not switch 5x on and off the rear fog light)
4. Press 3x hazard lights button (do not switch 3x on and off hazard lights)
5. Then the battery symbol in the speedometer should flash 3x quickly.
If it does not flash immediately, wait 20 seconds.
 

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Hello from Germany

Look at your car battery negative pole. Do you have a BMS (Battery Monitor Sensor)?
Only cars with Start/Stop system (in Europe) have an EFB battery (Enhanced Flooded Battery) and a BMS.
All others have normal lead-acid batteries in it. Lead batteries do not have a BMS.

For a reset of the BMS:
1. Switch on ignition (do not start engine)
2. Switch on dipped beam
3. Press 5x the rear fog light button (do not switch 5x on and off the rear fog light)
4. Press 3x key hazard lights (do not switch 3x on and off hazard lights)
5. Then the battery icon in the speedometer should flash 3x quickly.
If it does not flash immediately, wait 20 seconds.
I have a US SE without start/stop and mine has a BMS and can be reset. not sure about this method though seeing as US versions don't have a rear fog light switch. maybe you mean defroster?

sure fire way is to do it with forscan service procedure "reset battery monitor system" and follow on-screen prompts.
 

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Alternatively you can disconnect (positive and negative pole) car battery over night.
This also resets BMS.

This method resets several modules to Manufacturers Status.
Door Control Unit (DCU) (if you have (re-learn Windows lifter)),
Engine Control Modul (ECM) (re-learn (drive)).
 

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Discussion Starter #17

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I was being serious lol. What is that program?

Sent from my SM-G920T using FF Mobile
I seriously thought you were screwing with me lol

Download FORScan

how to get extended license: FORScan forum ? View topic - Standard and Extended licenses for Windows

you must have an extended license to be able to do any module configuration changes to central config like focccus does

i think you can reset modules in the services procedures tab without one, but an extended license is fast and free and opens so many doors you might as well get one

as far as adapters go, save your money and time and get the obdlink mx bluetooth. don't waste your money on the wifi version it doesn't work so well.

I have used an original elm once before but it is limited in use because it cannot access ms-can

the obdlink mx is well worth the $80
 

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i put anew battery in a few weeks ago didnt reset battery module voltage showed up to 14.5v 130 amp on torques pids , last night i reset battery module with forscan program and laptop and usb elm 327 now volts tops at 13.7 v amps about 60 a
 

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i put anew battery in a few weeks ago didnt reset battery module voltage showed up to 14.5v 130 amp on torques pids , last night i reset battery module with forscan program and laptop and usb elm 327 now volts tops at 13.7 v amps about 60 a
resetting the sensor definitely hasn't changed anything about your battery's health or power,

and those values will change based on what accessories are running in the vehicle, whether moving or stationary, how long the vehicle has been running, etc.

all the sensor does is through the BCM calculate the needed charge for the system to power everything that is running. the system is probably requiring less power because now the new battery is operating at an optimal level for the system instead of having to operate at higher volts to do the same things with an older discharging battery.
 
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