I know it's been a while but I'm going to revive this forum post. I haven't posted in some time, but that also means I've done a lot since then. I've completely replaced my PCV system, new OEM plugs regapped, new coils. I am also running a custom stage 2 tune that compensates for the extra airflow from the mishimoto intake I have (since some people swear that P1CE700 is due to the tune not compensating for the extra airflow from bigger inlet). It's winter now, I am still getting the code here and there but not as often as I was in the summer. The temps are way colder now. After speaking to countless of mechanics, 45 owners pushing their cars, and many others who are experts in this platform, it seems like it is caused by a few things.
#1. Tune not adjusted for extra airflow if you have an aftermarket air filter. You need to talk to your tuner to adjust for extra airflow. Stay away from off the shelf tunes. Only custom tune your car to avoid many, many, many issues. I know from first hand experience. This is probably the most important advice here.
#2. Car overheats causing turbo wastegate to open and reduce torque, this then have a chain reaction and activates the P1CE700 code, which naturally puts the car in soft limp mode (reduced power and torque). You need to upgrade your center and side radiators, but the one that gets affected the most is the transmission cooler, which is located on the bottom of the front bumper. This is likely the reason to why your torque is reduced after holding WOT for 3+ gears, and it will trigger the code.
#3. Leaks in the PCV system. I would not change the PCV system unless I do and check every other step (as this is the most expensive repair). You can pressure + smoke test the system to see if there are any leaks. If not, look at the other remedies. The PCV valve can be stuck from gunk, which would require a complete PCV system replacement but do not do this until you do all the other steps.
#4. If your timing chain is starting to lose tension, it will trigger this code, especially when you give it juice. This is also another expensive repair so I would look at all the other remedies first.
#5. Your turbo wastegate actuator is starting to go bad, causing it to not close 100% on WOT, triggering the code. I would check if there is any play on your actuator. If there is, it would require the turbo to be taken out and repaired.
#6. Turbo vacuum pump is bad. It's also called pressure transducer. There are 2 inlets which means 2 hoses connect to it. It can be found behind your oil cap. I would take it out and blow on it. If you can blow through it, it's leaking and must be replaced. If it's blocked, it's working perfectly.
#7. Using non OEM spark plugs or incorrectly gapped spark plugs. A bad ignition coil will also cause this code to come up. These would 100% cause this code to trigger and put you in soft limp mode, especially when you get close to redline.
#8. If you get this code with the exhaust flap code, then the exhaust flap must be fixed or removed and put a module on the wire to disable it as this would also trigger the code.
In my case, the code is triggered because I'm overheating and my tune is not perfect. My fix would be to upgrade the transmission cooler and also fix the tune to adjust for more airflow and give the waterpump a more aggressive profile. The water pump is probably the biggest issue with this car, especially when you're tuned and going WOT for 3+ gears. Hopefully I helped everyone here, these are very sensitive cars so unless everything is perfect, it will put you in soft limp mode. It's a good and a bad thing. You can't blow it up as there are so many failsafes but it's also very annoying as the P1CE700 is such a generic code, it's hard finding the exact cause.
Good luck everyone!!
