New ecu Okay

I think you need to have the BCM inspected or replaced if POSSIBLE .also,thoroughly inspect all wire connections, particularly in the regions where the mechanic had been handling the auxiliary battery.There could be a loose connection or any daamged wire

battery good?? maybe ignition switch failure or fuse blown

My Renault truck that was parked refused to crank havent confirmed that the truck ECU, starter and key are all okay. i highly doubt it has a kickstarter???

Hi, you cannot diasble the immobilizer by removing a chip. What you have to do is trick the ecu into believing you are using the correct key. There are bypass systems on the market for this purpose. Just make sure you get the right one for your car.

probably fried the ECM
substitute it with a known good one and go from there

Make sure an OBD reader is used to make a connection to the car's ECU/ECM. If no connection can be made, then you can remove the ECU and test it for current and resistance. If either of those tests fail, your car needs a new computer.

It could be a short in the wiring- a broken wire, or wire stripped of insulation, and touching metal somewhere. If you could look at a wiring diagram and find that circuit the fuse protects, you should be able to check the wiring without a lot of difficulty. The wire would enter the ecu on a certain pin number, and then you could check the resistance on the wire with a multimeter-with key off, and battery disconnected before unplugging the ecu. You will have to check the wiring all through the circuit, so you really do need a wiring diagram. If the wiring appears to be okay, then suspect a bad ecu. Used and reconditioned ecu's are all over e-bay. Pretty sure you could find one for your car. I just recently bought a used ecu from e-bay for my '87 Sentra, cost was $24.99, some place called auto computer wholesalers. And it works as good as a new one. Or as good as my old one, turns out that wasn't my problem, but I just kept it in the car.
Don't forget to disconnect the negative battery terminal. The ecu in those has constant power to the ecu, even with the key off. So never pull off the ecu connectors with the battery connected.
For a wiring diagram, buy a Haynes repair manual. Or register for free at autozone.com, giving make, model, year, and engine size if applicable. The repair guides do have some wiring diagrams, just not complete maybe. Or if interested, you can buy a subscription for $16.99 a month (or under $30 for a full year) from eautorepair.com. It is a DIY site by Mitchell, and with a very extensive amount of help and information. I had a one month subscription there, after getting very, very depressed with my Chilton manual. Couldn't even find a credible wiring diagram for my '87 from Chilton.

check ignition fuse if fuse okay problem in ignition coil or ignition module crankshaft sensor camshaft sensor.fault could be in the ecu best to code scan vechicle before buying new parts.many things will cause no spark conditions.

Sometimes the code reader will not read the Mopar/Jeep codes. This is different system, CAN system. Drive to your local AutoZone to get your codes from your ECU/ECM.

i assume you checked all your fuses. if you have no spark coming from the distributer you need to see if there is power going into it. and the ecu tests okay you might have a bad distributer.