I have Mercedes s400 and i changed both converter but i need to charge the high voltage battery but i don’t know how to do it

Repair Help Mercedes-Benz
1

I have Mercedes s400 and i changed both converter but i need to charge the high voltage battery but i don’t know how to do it and i get this fault code 0c7800

2

Hello,

Maybe this link may help. P0C7800 - Hybrid Battery System Precharge Time Too Long

3

@elbertnyoucanic-com i have traid all in the video but the contactor doesn’t want to change to activ

4

It’s probabily a faulty high voltage battery that needs to be replaced. It’s very simple procedure. Disconnect the 12 volt battery first. The high foltage battery has 2 connectors that easily come off and the ac cooling lines. The hardest part if that you need to remove AC refrigenrant first from the system and then recharge it.

5

Most likely, the high voltage battery is defective and needs to be replaced. The process is fairly easy. First, disconnect the 12-volt battery. The ac cooling lines and two readily detachable connectors are features of the high-voltage battery. P0C7800 - Hybrid Battery System Precharge Time Too Long removed link