Start up power loss/ abs light

[OCO0012]

Gday when I start my my 06 VZ between auxiliary and tuning over the engine I loose power to the interment cluster, radio and power sauce. The abs light comes on beeps and then disappear as if noting is wrong with no history codes or anything. When turning over the engine It also sounds like the battery is mildly flat even when fully charged. I tried hooking up my multimeter to see what the voltage drops to when cranking and it goes down to 9.64 volts on a 520cca battery. The car has been doing this for around two years shortly after I got the new battery. The battery has also been tested and it says it is a good battery. I believe what may be happening is the drop in voltage causes the CPU to reboot causing the issue the question is what is causing

 

[Trevor loves holden.]

Need to do a load test even if the battery may look good on volts but totally different under a load.