Salvage vehicle

[Fabian]

I have a salvaged 2010 Nissan Sentra no start/ no communication condition no fuel no spark crank and compression is good.
Battery new, fuel pump new
I have bench test the pump I submerged it in water and it works I am getting no power to the pump and no spark at plus injectors getting single to spray the fuel pump fuse is good the fuel pump relay is inside the power distribution box it’s not replaceable.
there’s a warning light for SARS and ignition no longer locks when they towed it to me battery was completely dead causing me to have to do a key relearn which other than. Now it does operate the automatic door lock agian the car still dont Start
my question is where do I start scientifically it being a salvage vehicle that had front end damage that severed the wiring harness and several locations the whole thing from the dash to the engine is a rats nest covered in a ? of electrical tape.
The car ran for a year and then just one day not start anymore.
Customer had his friend look at it first I suspect he not telling me the whole truth about what he messed with.
Do I Start with the communication problem do I go after the computer could it be a ignition problem to because of the doing wheel is not locking.
because it died do I need to have it be rechipped first
Body control module located in the dash is a square looking thing covered in about 2 inches of electrical tape..
Do I break out the switchblade and start cutting off electrical tape see what the wiring looks like ? I accepted it because nobody else wanted it and I like a challenge but I want to do this one in a strictly scientific approach I get power to the scan tool but no communication and for that it goes through the body control module or B.C.M which just to reach I have to take apart the whole instrument panel and Dash
The CVT harness looks like it was smashed at one time
Apparently when they were repairing it they were not able to understand how to take off modern harness connectors what they didn’t understand they broke of that goes for the VSS ,The cam, the knock, the crank, The Alt. and up stream 02 sensors they broke off the connector tabs
the connectors go in but they don’t lock and I know it could cause a short at the connector.
all grounds are good and it had like 20.
I have a dealership service manuel but it relies heavily on a scan tool and I have no communication so scanner is not an option right now just a D.V.O.M and a test light
I feel like the service manual been keeping me in circles becuase of the need for scanner inputs that need to be done for proper diagnosis I do have it diagnosed down to either the power control box or the ECM both are about $350 each not counting the cost of reprogramming that has to be done at the dealership for the ECM..
I’ve checked all the sensors for shorts the only one that came up was the crank sensor which I suspect was the problem in the first place..
Oh yes they did work on it without disconnecting the battery..
I want to start from scratch and look at it scientifically this time my brother-in-law is a Master Tech with a Toyota dealership I asked him for input he told me do I look like I work on Nissan’s so much for Master techs who buy the answers to the ASE test online I earnd my master tech patch the hard way and I’m still earning it.

[Schrodinger’s Box]

Do you have a 5volt reference????

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