Check the 7.5 amp backup/radio fuse in the engine bay fuse box is good. Pulling that fuse will reset the TCU and ECU.

What was the OEM part number on the old and the new TCU?

Turn the key to the II position, but do not try to start the car. Does the check engine light turn on for about two seconds, then turn off? When the check engine light is on, the fuel pump will turn to pressurize the fuel system. The pump makes a faint buzzing/whirling sound from the back seat. Turn off the radio, blower, etc... and listen carefully.

 

I'll check tonight and report back. Thanks for the help!

 

I can't believe it, but out of no where the car started! Yay!

Based on PAhonda's suggestions, while I was checking the check engine light, here's what happened:

First, when I turned the key to the II position, the check engine line did not turn off after 2 seconds. Instead it stayed on and the green "s" light continually blinking also. Then, I left the key in the II position while I was listening for the fuel pump and re-reading PAhonda's post.

While I was doing that, after about 2 minutes of just sitting there and with the key still in the II position... all of a sudden... the car made a buzzing/whirling and click sound (similar to what an auto seat belt sounds like when it moves into place) and the check engine light went off. I excitedly responded "Whoa! what was that??!"

I then tried it again to see what would happen.

I turned the car off and then again put it back into the II position and the car did the exact same thing again. The check engine light stayed on and the green "s" light blinked continually. Then after a few minutes... again... the car made the same buzzing/whirling and click sound and the check engine light went off.

I then tried it again this time to record it.

I turned the car off and then again put it back into the II position, but this time the check engine light did turn off after 2 seconds. "Ah-ha!" I said this time, something different.

I then tried it again a couple more times to confirm and each time the check engine light would turn off after 2 seconds.

So... I then tried to turn the car on and voila, the car started!

Not sure what happened but it worked.

If anyone can explain it that would be great, but we're really happy.

Hopefully this means it's really working.

 

If/when the problem returns, you will likely have to troubleshoot the problem. When the check engine light does not turn off, try shaking the key to see if that helps.

Also, short that service connector and read the codes. There are numerous videos on youtube that will show you how to do this.

 

So I thought the car was working (based on my post above) and the next day I check, the car is again not starting. I tried letting the car sit with the key in the II position to see if I get the same response as above, but no luck.

So any help is appreciated!

Here's a video of what is happening. Something new this time. I know see some lights blinking on what looks like near the back of the TCU.


Some additional information. The fuse for the ECU looks good. I've also attached a image of the OEM on the TCU

 

Since the Check Engine Light stays on most of the time and the car doesn't start, you should jump the service check connector as I previously mentioned to try to get the trouble code(s).

Issue may even be due to a faulty ECU. A faulty TCU generally won't cause the car to not be able to start; but, a faulty ECU can cause it to not start.

Try to get the trouble code(s) first.

 

After long break... Now back at this again. I tried to jump the service check connector, but could get a consistent connection. Will have to find something that works better than a paper clip. In the meantime...

Back to the red light flashing on the back of the TCU. Maybe deciphering them will lead to a solution. Here are the patterns:

Pattern #1: solid-1-2-3-7-8 (this occurs right after turning car on)
Pattern #2: 1-2-3-7-8
Pattern #3: long-4-1-2-3-7-8
Pattern #4: long-4-1-2-3-7-8
Pattern #5: long-4-1-2-3-7-8

Any ideas?

 

Just a wild thought... did you do anything to the gear position sensor? if it is out of position, the engine will not start because you can only start it in "P" and "N". It may light up in P , but the gear itself may be in "R" or "D".

 

Not sure of your codes. Here is a good video on pulling codes.

 

I don't think I did anything to the gear position sensor. I actually don't know what that is. I only removed the glove box, blower motor for the heater (and relevant connections), TCU, and ECU. The blower motor, TCU, and ECU have all been put back in place.

So, if that sensor is involved in the removal and replacement of those three units.... I didn't touch it.