Charging system issues

[Bdizzle]

On my 3rd battery currently og replaced in april with a napa batttery then again 2 weeks ago and new alternator my 19 lariat has been in the shop for a week now. started off as I was getting the "engine on due to vehicle charging" message on my auto start stop screen dealer told me the battery and alternator were both bad replaced both still got the message every single day even though i drife every day 20 miles one way, so they contacted fird engineering and they thought it was the BMS sensor was bad replaced that now its throwing up messages about charging system fault both the dealer and Ford engineering have no clue what's wrong. Anyone have any experience with anything similar?

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[airline tech]

Put an Ohm Meter across the 225 Amp Fuse - I bet it is blown, The 225 Amp fuse is on the BMFL on top of the battery.

 

[Bdizzle]

I'll have to ask them to try that, the service advisor and tech won't be back until Tuesday ill run that by him to try thanks ! Im contemplating trading the truck in if the issue doesn't get fixed. I've also noticed my mpg tanked as soon as I started having those charging issues too was getting 24 mpg in the summer 22 winter and it dropped to 21 summer 19 winter

 

[Frenchy]

A couple of possibilities I'm sure. With that said a bad alternator can cause a battery to go bad. The same go for a bad battery causing an alternator to go bad. With all that said I suspect there is something else going on. If I were there I would be able to figure it out. Unfortunately I. Not

 

[Bdizzle]

That's why I thought the sensor was bad or the bms needed to be flashed back to factory or something since they already replaced the alternator and battery saying both were bad the alternator was charging at like 13.6 i think but all I know is I hope it's sometbing dum and cheap

 

[Frenchy]

As a thought has the BMS been reset ever since replacing the Battery or Alternator? I know it sounds silly, but the BMS is a special system to say the least

 

[Bdizzle]

Yeah they reset it after replacing both that was the first thing I asked them when it started popping the message up again

 

[airline tech]

I am actually surprised they can’t find the issue, if all has been changed then it is down to wiring issue as they should easily find a bad fuse, that fuse can be partially blown creating high resistance. (Should be .02 Ohms) between each leg of it.

Is this generating any codes? I am sure it is along with the Check Message and Battery Light
If so, what is the code or codes?

Now if the fuse is good and all has been changed except the PCM and BCM then it's down to the wiring and mainly the control (LIN) circuit for the voltage regulator, its PWM -Pulse Width Modulated and can be seen on a Pico Scope.
They need to look for the On/Off trigger from the PCM to the Voltage Regulator in the Alternator
If the max voltage output is indeed 13.6 volts, the programed default voltage if a failure on the LIN circuit is around 13.5 volts.
As I do not know if that is the Max Output or was it just the voltage being generated at the time of the test.
So, they need to check wiring between the PCM and the Alternator - (LIN Circuit)
and the (LIN) circuit between the BCM and the BMS (Sensor)
if no issues with above checks, then the issue is in the Data Bus (Communication)

Check the Data Bus (Communication) between the BCM and PCM
And the Data Bus (Communication) between the BCM and IPC.

It sounds like a lot but should be a simple find if you dig into it, and a code will help in pinpointing it down, as of now they are NOT troubleshooting they are shot-gunning parts at it without doing any REAL TROUBLESHOOTING.
A Meter and Pico-Scope and possibly a network test will reveal the fault and should take no more than a few hours to find it.
My first strong hunch by the info I have is the 225-A fuse.

 

[Bdizzle]

Unfortunately they aren't going to be back in the shop till tomorrow to go and see if it's psitting out any codes with the message as it didn't happen till they replaced the sensor I just see the message pop up on my ford pass app and if that fuse doesn't fix it I'm gonan try explaining what you just said to them. I think they started throwing parts ay it cause they thought it was just a bad battery then further testing showed that the alternator was bad too.
But thank you I've been looking around through different forums and places trying to find any insight to what it might be and I cannot really find anything. But it's odd the dealer and Ford are both that stumped with this

 

[dtech]

I am actually surprised they can’t find the issue, if all has been changed then it is down to wiring issue as they should easily find a bad fuse, that fuse can be partially blown creating high resistance. (Should be .02 Ohms) between each leg of it.

Is this generating any codes? I am sure it is along with the Check Message and Battery Light
If so, what is the code or codes?

Now if the fuse is good and all has been changed except the PCM and BCM then it's down to the wiring and mainly the control (LIN) circuit for the voltage regulator, its PWM -Pulse Width Modulated and can be seen on a Pico Scope.
They need to look for the On/Off trigger from the PCM to the Voltage Regulator in the Alternator
If the max voltage output is indeed 13.6 volts, the programed default voltage if a failure on the LIN circuit is around 13.5 volts.

AT - is the voltage regulator is in the alternator - thought just the diodes. with the regulator being part of the pcm. what wouldn't work if that 225 amp is blown ? I'd also suspect wiring with the dealer too lazy to troubleshoot, easier to replace parts.

 

[REDWM]

I am actually surprised they can’t find the issue, if all has been changed then it is down to wiring issue as they should easily find a bad fuse, that fuse can be partially blown creating high resistance. (Should be .02 Ohms) between each leg of it.

Is this generating any codes? I am sure it is along with the Check Message and Battery Light
If so, what is the code or codes?

Now if the fuse is good and all has been changed except the PCM and BCM then it's down to the wiring and mainly the control (LIN) circuit for the voltage regulator, its PWM -Pulse Width Modulated and can be seen on a Pico Scope.
They need to look for the On/Off trigger from the PCM to the Voltage Regulator in the Alternator
If the max voltage output is indeed 13.6 volts, the programed default voltage if a failure on the LIN circuit is around 13.5 volts.
As I do not know if that is the Max Output or was it just the voltage being generated at the time of the test.
So, they need to check wiring between the PCM and the Alternator - (LIN Circuit)
and the (LIN) circuit between the BCM and the BMS (Sensor)
if no issues with above checks, then the issue is in the Data Bus (Communication)

Check the Data Bus (Communication) between the BCM and PCM
And the Data Bus (Communication) between the BCM and IPC.

It sounds like a lot but should be a simple find if you dig into it, and a code will help in pinpointing it down, as of now they are NOT troubleshooting they are shot-gunning parts at it without doing any REAL TROUBLESHOOTING.
A Meter and Pico-Scope and possibly a network test will reveal the fault and should take no more than a few hours to find it.
My first strong hunch by the info I have is the 225-A fuse.

I would like you to spell out all the abbreviations for those of us who are not auto mechanics, please. I finally figured what BMS stands for (battery maintenance system or sensor) but don't know PCM, BCM, LIN or IPC. Trying to learn! FYI, my ASS wasn't working, the USB wasn't working when it was cold and I was getting several "shutting of system to "save battery" messages. I bought and now use a battery maintainer regularly. Noe the ASS works when it warms up and the engine is in normal operating temp plus the USB works and no more save battery messages.

 

[Grandaccess]

A couple of possibilities I'm sure. With that said a bad alternator can cause a battery to go bad. The same go for a bad battery causing an alternator to go bad. With all that said I suspect there is something else going on. If I were there I would be able to figure it out. Unfortunately I. Not

I have just in the last month dropped into the 19 mpg range for winter, it could be something up with the Winter gas mix now
depends on where he is in N.Y I am closer LOL I am Upstate in Binghamton

 

[Bdizzle]

Buffalo and the winter brew usually drops my milage by 2 mpg but I've taken an extra 2 mpg this year all year round

 

[airline tech]

AT - is the voltage regulator is in the alternator - thought just the diodes. with the regulator being part of the pcm. what wouldn't work if that 225 amp is blown ? I'd also suspect wiring with the dealer too lazy to troubleshoot, easier to replace parts.

By all descriptions the Voltage Regulator is internal to the Alternator, the PCM is the control for the regulator via (PWM - Pulse Width Modulation)

The 225-Amp fuse is mounted between the battery (+) and the Alternator main feed cable.
So, if this is blown the alternator output (charge) will stop at one leg of the fuse.
Now this is a (2-way) communication if the Alternator is not sensing battery voltage from that input it stops charging or defaults to 13.5 volts, but the battery will not be able to get the charge.

The BMS Sensor, has a (+) input lead going to the (+) post on the battery, if the BMS is not seeing a charge voltage it will generate a BMS sensor failure, which is why the replaced the sensor (Shot-Gunned) part.

 

[airline tech]

I would like you to spell out all the abbreviations for those of us who are not auto mechanics, please. I finally figured what BMS stands for (battery maintenance system or sensor) but don't know PCM, BCM, LIN or IPC. Trying to learn! FYI, my ASS wasn't working, the USB wasn't working when it was cold and I was getting several "shutting of system to "save battery" messages. I bought and now use a battery maintainer regularly. Noe the ASS works when it warms up and the engine is in normal operating temp plus the USB works and no more save battery messages.

PCM - Powertrain Control Module
BCM - Body Control Module
BMS - Battery Managment System
IPC - Instrument Panel Cluster
LIN - Local Interconnect Network (It is a single wire - Send / Receive) data communication bus.

So, for your instance, overnight battery voltage was dropping below 11.5 volts, the system was disabling modules to save battery power (voltage) for engine starts.
Prolonged under charging increases the IR (Internal Resistance) of the battery, using the battery maintainer helps in repairing (fixing) the high IR, The IR is important as it is a factor on how well the battery accepts and holds the charge.

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