Help, multiple codes after first EGR, manifold Clean

Tips are urgently needed. So I'm not mechanically inept, but the Prius is completely new to me. 2014 Prius with 65k miles. I just followed the Nuts videos on how to remove the EGR and manifold for a complete clean. It was definitely in desperate need and I carefully cleaned it all. I thought I reinstalled everything well but now have one extra 12mm bolt (edited) and when I started the the car it shows the check engine light and throws P0102, P0133, and P261C.

P0102 - Mass Air Flow (MAF) circuit is low
P0133 - various possibilities:
Faulty Front Heated Oxygen Sensor Bank 1
Front Heated Oxygen Sensor Bank 1 harness is open or shorted
Front Heated Oxygen Sensor Bank 1 circuit poor electrical connection
Inappropriate fuel pressure
Faulty fuel injectors
Intake air leaks may be faulty
Exhaust gas leaks
P261C - water pump circuit low

Are these codes that mean I need to take it apart and start over or is it something I must let it think of and maybe they clear? A little, and I do mean little, coolant leaked out when disconnecting things despite clamps, but I'm stumped, and frankly terrified as I don't get the Prius electronics.

Any help is greatly appreciate. Currently it is permanently parked in the garage.


Read more: P0133 TOYOTA HO2S11 Circuit Slow Response

 

Desperate need is probably strong, but it was grimy with a decent amount of grunge all around. Previously I've only had old fashioned fuel injection and buildup is a new thing for me. Purple Power soak cleaned up everything amazingly and in not all that much time so it probably wasn't as bad as I thought it was. Definitely not layers of cake like some of the photos I've seen.

I'll check the 12v and top it off overnight with a trickle charger.

I correct myself. It is an extra 12mm, not a 14mm. It is one of those from the interior for a heavier mounting. Now I suppose I have to take it all apart again, ugh. Is there a list of just what nuts are 14mm so I can narrow down the search. The NutAndBolts videos were great, but I do wish someone had a step by step written version.

 

So I found the 12mm, it belonged in the upper EGR cooler bracket. I missed it watching the video real time on my phone. I’ve since put the videos on a laptop and will take it apart and do it again tomorrow.

My next concerns are if I misrouted a hose or missed a plug. I didn’t think I touched anything on the water pump. I also thought o signed all connections. Now I am having doubts about possibly having brushed some gunk into the fuel injectors when cleaning then.

Worst case I’ll be making an expensive trip to the dealer.

The oil catch can has already been bought, I just need to source a bracket. I don’t want to do this very often.

 

Sadly I am only now realizing this. I thought I was being quite intelligent doing out all at once. I know have experience. If I had wisdom I would’ve learned from others experience.

Methinks it will be a tedious day.

 

Success. Thank you for the advice. After topping off the battery the voltage is still a bit low AND I had missed the plug for the water pump. Having an electric water pump is completely new to me and I simply missed it in the video reassembling everything. With the topped off battery and the water pump actually plugged in the car is happy as can be.

I was unaware that low voltage could cause issues. I will pick up a battery tomorrow. It looks like the dealer has the best warranty.

 

MAF was connected but the intake hose to the side of the air box had a small pinch which may have affected it. Either way, I’m happy.

As for misspelling the name, I might get around to spelling it correctly, but I won’t add the @.

 

Not being a forum junkie nor on Twitter that is actually news to me. Seriously, thank you for teaching me something I didn't know!

Separate question. 12v battery resting state is 12.73v, engine running 14.3v. Is that still good or do I just want to take it in for a test somewhere?