I am trying to figure out why my 2012 Mazda 3 skyactiv pcm won’t read on any obd2 reader I swapped engines using original wiring and everything else just the engine was changed car has been sitting with out a battery for four years everything so stalled and plugged in properly and I went to them the key and the immobilizer is on and the pcm won’t read
I get security code 16 ( no communication with cluster ) so I changed clusters to one out of a 2013 and reset the battery and still no pcm communication I have checked every single fuse and relay in the car all good and cleaned all connections and re installed them all and still same thing I need help asap I don’t want to bring it to the dealer for obvious reasons it would cost a fortune help me please I can provide any info as needed

 

Start with a wiring diagram and make sure you have all the power & ground feed to the PCM.

 

Ok so where do I get wiring diagrams??? and where do I start looking for this problem ??? What is causing it the car sat for 4 years I just replaced the engine and touched nothing else so why would I all the sudden have this problem ??? What would cause the computer to not read ?? I’ve tried a new cluster I’ve tried another pcm and still nothing won’t read

 

Does anyone have a service manual they email me ???? For the 2012 Mazda 3 gs-skyactiv 2.0l n/a

 

Today we checked all the wiring and fuses and relays and everything seems ok
can anybody help ?
no pcm communication at all
power to obd port yes
turn Signals work but don’t come on the cluster
4 ways work but do come on the cluster
Bluetooth will not connect
temperature will not display on screen
bunch of lights on dash all light up
everything else functions as normal
key fobs work
remote start try’s to engage as it should
keys are not recognized will not start
can’t program keys because pcm will not connect at all to any scanner tool
i have owned this car since brand new and remote start was installed before pick up and this car has sat in the yard for 4 years( 2020 til now ) with no battery because engine needed replacing
can anybody point me in a directions as to what is causing this no communication with pcm issue ?