Crank but no start - no dash lights or gauge movement, no output from OBD2

Hi Tundra techs,
My 2016 Sequoia decided to not start this afternoon. It cranks strong but will not catch. Some observations:

• Normally I can "bump" the ignition key to the start position and the computer will continue to crank the engine even after I release the key (similar to a push-to-start). However that behavior is not happening now. It simply cranks as long as I hold the key like a traditional ignition switch.
• The dashboard is only illuminating the door-open light and the "P" shift indicator. The gauges are all dark (no backlight regardless of brightness setting and cycling the headlights) and not receiving any signal (I shined a light on the fuel gauge and it sits below the "E". I know it's closer to 1/2 full [pic attached])
  
• Plugging in the bluetooth ODB2 sender blinks a short green light and it "connects" to my phone, but the Torque app never connects. Verified it's working fine in another vehicle.

It feels like either a bad ECU or bad ground to me. Since it happened so suddenly I am leaning toward the computer. Plus I don't know where to start hunting for this specific ground.

Appreciate any insight or advice.

Demo: https://photos.app.goo.gl/1ttKfLGB7vp3mCcm9

Thank you for reading!

 

My brother-in-law reminded me that I omitted the fact that I did have a remote start installed about five years ago. It's been working fine and I'm not sure the immobilizer would kill the dash lights but it's important to know that wires have been tampered with.

 

Brief update: I had it towed to the remote installer's shop and they put three hours into diagnosing and couldn't find the problem. They tried "jumping" the CAN network but still no joy. They removed the remote start module and verified all wires were secure.
I towed it back to Toyota who insisted on removing all traces of the remote start wires. They have several hours into it (at $260/hr) and are going through the entire harness one branch at a time. Will provide an update when I learn more.

 

Received the vehicle yesterday in repaired condition. No external wires were found to be at fault. The engine computer was determined to have an internal short. They said a foreign substance contaminated the computer and caused the short. The substance they were referring to was the white lithium grease I used to lubricate the closing latches since they were bound with ten years of dust. This was done during my preliminary inspection, after the fault, so I disagree that this was the root cause
I would like to have the computer analyzed to better understand where the short occurred. Also considering getting it rebuilt so next time the cost could be considerably less than $3,200.

 

Older ECUs suffee from leaky capacitors. My 93 SC400 suffered from constant fail starts, after I got it the ECU rebuilt it doesn't fail to start any longer.... in your case it may be 50/50.