renault master low battery in cluster

[coder5]

Hello
I have a renault master camper van with the fault code dtc920f81
upc-altenator link invalid. I would be grateful for any help on this code.
Regards
Larry.

[gwiazdamb]

Hello
I have a renault master camper van with the fault code dtc920f81
upc-altenator link invalid. I would be grateful for any help on this code.
Regards
Larry.

You have a damaged LIN between the alternator and the upc or a damaged voltage regulator in the alternator

[coder5]

thanks for reply. can you explain to me what is lin between altenator and upc. as we have two camper vans with same fault code
Regards
Larry

[gwiazdamb]

This LIN is used for communication between the alternator and the UPC.
Lin works similarly to k-line, you have about 12V on the communication line because the line is pulled up to +12V with a resistor and the low state is forced by the driver.
The alternator itself probably doesn't say anything, but only responds to control and queries from the controller