I have a code 26 as soon as turn on the unit goes into selftest but it just stay in selftest and in the vehicle manager display shoy code 26 i ran all the tests and all passed except for the O20 which is ramp i swapped the HCm and PWB from another unit and its doing the same thing, i checked all the fuses, cables and short to frames and everything its good.

I really need help with this, thank you