Charging System Service Now

[Paz083]

Own a 2019 Lariat Ranger. Keep getting the error code. Charging system Service Now light coming on. Hooked up OBD and showing that alternator is charging battery. Battery is good. Did anyone get this code before. Someone said it could be the Battery Current Sensor at the terminal. Battery was changed September 2023. Was getting this message intermittently and now it is on all the time. Anyone else had any issues like this ??

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[airline tech]

any codes found when scanned with the reader?

 

[Paz083]

Brother in Law said it was that there were no codes found.
he is stumped too and he’s a decent mechanic. He suggested the BMS sensor might be bad.

 

[moorejl57]

Try unplugging the BMS sensor and see if there is a change.

 

[airline tech]

Brother in Law said it was that there were no codes found.
he is stumped too and he’s a decent mechanic. He suggested the BMS sensor might be bad.

It is possible, but generally will trigger a code, you said verified charging but what is the charging output.
If a fault in the system - the default output is 13.5 volts - steady

so, this needs a Live Data Pid, monitor and look at the Gen Voltage (Actual vs Desired) readings both with the headlights on and off (load / no load)
This is most likely the scenario you have, you may try disconnecting the BMS sensor with the scanner (Live Data) and see if the voltage jumps with it disconnected and the IPC message goes away.
This issue would tie into the LIN communication circuit for the Generator Control (output)

 

[Paz083]

Took the terminal off and waited a 15 minutes and put it back on. Still the same thing. The BMS sensor is on the negative battery terminal. Maybe he’s right I should try and replace it. Found Ford OEM sensor for 60$ maybe it’s worth a shot.

 

[ControlNode]

Scan it with Forscan, it can hit all the modules and show codes that a base ODB2 scanner will not show.

 

[Paz083]

The output was right there at 13.8 I think it was. Gonna have to borrow his OBD reader again and see he has all that info on there voltage output and other things.

 

[cfhgarza]

I was getting that same message when my battery cable started coming loose

 

[airline tech]

Took the terminal off and waited a 15 minutes and put it back on. Still the same thing. The BMS sensor is on the negative battery terminal. Maybe he’s right I should try and replace it. Found Ford OEM sensor for 60$ maybe it’s worth a shot.

To be clear (took the terminal off) - you disconnected the neg term for 15 minutes or disconnected the CONNECTOR for the BMS sensor for 15 minutes with the engine running.

If you disconnect the CONNECTOR, you are bypassing the sensor and taking it out of the system, if the sensor was bad, the message should go away, however I am thinking you may be using a generic code reader, you need one to read (B) codes - Body and have a code you are not able to view with the code reader you have.

Now it is still possible as another mentioned, you simply have a lose connection at the battery terminals.
I will highlight looking at the (+) terminal (next to the terminal, does the little block (wedge) match the picture below?

Plus, I would get a meter and check for voltage on - BOTH - sides of the 225 Amp fuse, does the voltage match?
It is possible you have a partially damaged fuse and not allowing full voltage through it.

If all this is good, then a deep dive into the Live Data PIDs with a Bi-Directional control to force the alternator into MAX charge output, if this cannot be done then the alternator itself is bad or a control circuit issue (LIN)

There are various voltage checks that can be done, but the above are a basic start.

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