2008 Prius does not turn on/no ACC

Hello everyone!

I am having a hard time with this Prius I purchased for my sister. A little bit of back story - I purchased a 2008 Prius w/SKS that had been sitting for a good amount of time. Initially when I first purchased it, the only issue was a P0AFA DTC. RIGHT before removing the traction battery, the ignition would no longer come on or go into ACC; it was working before/randomly stopped working.

I didn't really think anything of it and continued with the removal of the traction battery. After sitting for 2 weeks while I refurbished the pack, I reassembled the vehicle to find it still had the issue.

(To put this into perspective, pushing the 'start' button does absolutely nothing)

I was unable to communicate with the ECU (obviously since the ignition will not come on) however, I applied power to one of the 'IGN' fuses in the interior fuse panel near the body control module and the CEL came on. I now can communicate but have an array of codes. Most of them I assume to be irrelevant considering the vehicle is not officially powered up. I managed to retrieve a B2796(?) (Memory foggy).

I am a Ford certified hybrid technician and only have access to ALLDATA. Based on my testing, I have diagnosed the key slot at fault, but something doesn't seem right. I am not sure how the SKS operates, and the key slot doesn't sound like a logical fix, but that's what my testing yielded.

Are these cars known for this issue? Does the key slot control keyless starting? Any guidance whatsoever will be sincerely appreciated.

To generalize my symptoms:

1.) Pushing the 'START' button does nothing (component tests OK)
2.) RKE functions work properly (I can still unlock/lock the car from the fob as well as push the button on the door handle)
3.) 12v battery is weak but I do have a charger connected (all testing done with system at 14v)
4.) A small red icon with a key occasionally blinks on the dashboard. Removing the key from the vehicle yields a yellow key exclamation symbol. No change disabling/enabling SKS with button.
5.) All fuses in both boxes are ok. I have not bench tested any relays.
6.) Inserting the fob into the slot yields no change. Slot is illuminated. Power button is backlit but not lit up (small green/orange led inoperative)

 

Thanks for the replies guys. I am a charging the battery off of the terminals directly, connections clean as well.
Since I work in a shop, I really only have time to mess with the car periodically, so I've been disconnecting the battery over and over. It has the same symptoms as the AM2 fuse, but fuse is good. Infotainment screen does not come on.

 

I have ordered a key slot for the car and it should be here in the next 2 days. I had to remove the hybrid pack again to replace the temperature sensor harness due to a biased sensor. I tried to start the car again for SnG's and ACC came on and the hybrid system even started and ran for about 10 seconds before everything lost power and reverted back to its original state of non-responsive power button. Although I have a new symptom now - the interior dinger no longer dings when the fob is inserted into the slot.

 

A bit higher than I anticipated going into it but I got for a steal, 250k

 

Well key slot did not fix it. In my rushed diag, I did not realize the key slot relies on other inputs; faulty inputs, faulty outputs. I have pulled the upper dash panel and went with another diag path. I have diagnosed the power source ECU at fault, but I am wondering if there is an input to the PSC that I am missing. Per the pinpoint test, connector P6 pin 11 voltage to ground should be 12v with power switch pressed and less than 1v not pressed. I am getting 0v either way.

Applying power to that pin makes the MFD come on.

I did also find P6-6 ground has 600 ohm resistance, however overlaying a ground had no change.

I found another pinpoint test that I am going to run through, but so far I have PSC Ecu suspected. I also found a thread describing the same symptoms, but was never updated with what Toyota found: I think my Prius not starting is going to be much different than the other posts here... | PriusChat