Hondata

my battery voltage is very low, i am using a rbb a71 ecu in a 2004 cl9, when i switch my car to ignition the fuel pump wont prime and the immobilizer light keeps flashing. when i plug in my flashpro it does not pick up the ecu. however the radio works and the lights etc. is my ECU dead?

You should start by either replacing or charging the battery and see if that resolves the issue.

i placed a fully charged battery in the car and the immobilizer light keeps flashing and the fuel pump wont prime. can you explain what is wrong>

additionally the ecu has the x not to it all of a sudden

The key an immobilizer must be matched by an Acura dealer.

This ECU was functional before in me car along with flashpro. It was already paired with the immobilizer

Check your fuses. Since this sounds like it is in a unsupported vehicle it is hard to say what could be wrong.

Dondada03 wrote:This ECU was functional before in me car along with flashpro. It was already paired with the immobilizer

I have seen that ECU sometimes looses "pair" with immobilizer when it's paired with not original Honda equipment.
Suggest you to re-pair immobilizer with ECU using Honda dealer equipment.