Between the ECU generator when the COM cable is plugged in, it charges with a maximum of 13 V, when disconnected from t

[PEU]

Hello!
I would like to ask for help, my 2011 diesel Fiesta has undergone a generator overhaul and an ECU inspection, everything was fine with both.

However, it still produces the original error: between the ECU generator, when the COM cable is plugged in, it charges with a maximum of 13 V, when disconnected from the generator, the charging voltage is 14.5 V. The charging error indicator sometimes lights up.

We also temporarily "changed" the battery on the car, but the situation did not improve.

Does anyone have any ideas / has this happened before?!

As a last resort, I will take it for a software update, but I admit I do not believe in this.
Thank you in advance for your ideas.

[tractmec]

Hello!
I would like to ask for help, my 2011 diesel Fiesta has undergone a generator overhaul and an ECU inspection, everything was fine with both.

However, it still produces the original error: between the ECU generator, when the COM cable is plugged in, it charges with a maximum of 13 V, when disconnected from the generator, the charging voltage is 14.5 V. The charging error indicator sometimes lights up.

We also temporarily "changed" the battery on the car, but the situation did not improve.

Does anyone have any ideas / has this happened before?!

As a last resort, I will take it for a software update, but I admit I do not believe in this.
Thank you in advance for your ideas.

I assume by "COM Cable" you mean the small wire connection on the Alternator(Violet Wire) and when you unplug that connection with the engine running you get 14.5 volts across the Battery and when the Connection is plugged in you get 13 volts across the battery?

This would be normal behavior as with that connection unplugged the alternator/Generator will be forced to charge on the Preset internal regulator(most likely set at 13.8-14.5 volts and what the actual value is will depend on the Battery state of charge and age/internal resistance and vehicle electrical load(Charge indicator light and charge error message should be on in this instance and a U0120:xx or U0469:xx DTC or similar "lost communication with Generator" DTC would be set in the PCM )!

With the Connection connected, the PCM(Over the LIN or Linear Interconnect network as part of HSCAN) takes over voltage regulation through a PCM(PID) parameter called GENVDSD or Generator Voltage Desired which is programmed up to a maximum of 15.9 volts and would likely be regulated around 13.0- 13.2 volts again depending on Battery condition and vehicle electrical load(Charge error indicators should be off)!

Trouble shooting something like this is going to require a scan tool connection and monitoring and reading any DTC's related to the charging system and resolving and clearing them first and then loading and running the GENVDSD PID and/or controlling it in FORScan or other scantool! (The Workshop manual and wiring diagram at www.cardiagn.com would be helpful for this)!

A PCM reflash(that would be an extreme case) is very likely not needed for this as in all likely hood the problem is intermittent and more likely to be loose(Deformed socket or bent pins) or corroded connections at the PCM or other connector(There is one other connection in that wire)! Difficult to see in those tiny connectors but that is where I would start