Prius 2007 How to Fix Error Code P1116 P1121

Prius 2nd gen (2005-2009) ran totally fine, but Smog Check wouldn't pass unless we get these codes P1116 and P1121 cleared.

P1116 - Coolant temperature sensor circuit stack for coolant heat storage system
P1121 - Accelerator position sensor range / performance problem





The Fix

The fix seems to be to replace the Coolant Control Valve.

Mechanics quoted me anywhere from $500-800
Depending on how much you make or your condition, this may be worth it. For me, $500-800 is A LOT of money.

Doing it at home is ~$200 + up to 3 hours of your time
( If I have to do it over again after my hand recovers, I can probably do it in a hour )


Here are the tools needed to do the Coolant Control Valve replacement on your 2nd gen Prius replacement yourself

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  • Toyota Coolant Control Valve - Part #16670-21010 - $120 - Make sure you buy the genuine Toyota. There are plenty of parts claiming to be genuine on eBay, but there are plenty of counterfeits floating around for $40, Several people on youtube / forums have stated their CCV has quickly given errors from buying cheap alternatives on Amazon or counterfeits on eBay. We bought ours from a local Toyota dealer for $115
    
  • Socket Wrench Size 10mm and 12mm - This is to remove the bumper / headlamp / Coolant Control Valve. If you have any mechanic's toolset, you probably already have these. If not, just buy or borrow a basic set from Amazon or your friends
    
  • Hose Clamp Tool or a Bent Nose Plier - $15 - This is to remove the coolant hose from the CCV
    
  • Cork Screw - $5 - This is to stop the coolant from spilling out too much
    
  • Coolant Refill and Funnel - $20 - This is to refill the coolant after all is done

I used the method to take off the headlight since I have bigger hands.

I still got pretty beat up

This video saved my life, BUT
1. I used corkscrews to plug the hose
2. I did not unplug the batteries

I also watched this video to refill my coolant properly

It really ended up taking about 5 hours honestly because I took breaks in between and was very careful with everything.