Solved
STM32H7 ADC3 (LL) code generator does not generate code for INJected channel config CubeIDE 1.6.1
This is the code that is missing (and i had to add myself):
ADC_INJ_InitStruct.TriggerSource = LL_ADC_INJ_TRIG_SOFTWARE;
ADC_INJ_InitStruct.SequencerLength = 2;
ADC_INJ_InitStruct.SequencerDiscont = LL_ADC_INJ_SEQ_DISCONT_DISABLE;
ADC_INJ_InitStruct.TrigAuto = LL_ADC_INJ_TRIG_INDEPENDENT;
LL_ADC_INJ_Init(ADC3, &ADC_INJ_InitStruct);(The HAL code generator does this correctly).
