No power on hills, MPG down, SOC low, PROBLEM FIXED

In the VVT system is the OCV "Oil Control Valve". After reading posts on no power on hills and a code P0011 I figured out the problem.

For over 2 years and possible 5 years, every time I would go on vacation with my 2006 Prius, I need to climb mountains. I live in Reno, NV and we are surrounded by mountains. The problem occurs when I would climb the mountains at high speed or high speed freeway driving, these symptoms occurred.

Battery charge drops quickly into the 25% SOC always into the bottom 1 or 2 bars on high speed hill climbing.
At highway speeds in level areas, the charge to battery never increases and the SOC gets lower and lower at speed of 65-80 MPH.

From Reno NV to Sacramento CA is 133 miles. Its all climb from Reno to Donner Pass on I-80 for 47 Miles.
Reno is at 4,413 feet and Donner Pass, CA is 7,227 feet. Originally I could drive this trip in cruise control at 65 MPH and never slow down, and still had acceleration if I pushed the pedal to the metal. But for years I would have this problem which went unnoticed as I seldom did long high speed trips or hill climbing. . The battery SOC would drain fast and stay low, the cruise would pop off and could not keep the speed which caused the engine to loss power with little or low power in a attempt to keep the speed at 65 MPH. I would need to move to the slow lane with trucks and would slow to 35-40 MPH until the hill ended. It then charged fast, speed increased, and it appeared normal. Around Reno, which is in a valley, it acted normal with a SOC 60-70, power to enter traffic, mileage 41-43 MPG.

Recently I would occasionally pop a code P0011 with a check Engine light, which would reset itself, and also cleared just by turning the car off then back on. The code only appeared at the end of high speed freeway travel. As a around town driver, this code never appeared and the car appeared normal except for slightly lower MPG. My driving habits changed recently as I now drive at high speed on the freeways 30 miles to Fernley, NV or Carson City NV to get gas. Reno added a 40 cents per gallon local gas tax and my goal was to show them. So I get out of the house and take a drive to fill up the tank and save .40 cents per gallon, have lunch, then drive home. But this is when the P0011 code started to appear recently, but not on every trip.

Everyone talked about the VVT oil filter so I checked that and its clean. But on the internet they said the main reasons for P0011 code which is the VVT advance system is VVT oil filter or the OCV "Oil Control Valve". I went to Auto zone and bought the OCV for around 98.00, installed it and went on the same roads that caused the loss of power.

Power has returned, battery stays at the target SOC 60% + per the Toyota manuals, will charge on flat high speed driving, keeps the set speed with engine power in reserve.
I would highly recommend you test your Prius at high speed requiring additional power as in climbing a hill with a load and if it falls spend the money and replace the OCV in the VVT system.

Finally I checked the old valve and it clicks as it should and has the correct resistance, looked clean, but was failing at high speed, higher engine and oil temperatures is my conclusion. The car now runs like new. If you have any of these problems, replace the OCV. The old valve passed the tests, but failed on the road.

 

I'm retired and I expected someone to nit pick my driving 30 miles for gas which is the only reason I found the code P0011 which lead me to research the problem. But I decided to give as much detail as I could and why I overlooked this code when it originally appeared. I changed my driving as a retiree spending the day enjoying the ride across beautiful Nevada. You must be a "Senior Member". I'm also a 73 yoa Senior. But the point is many Prius users have these symptoms and don't know the possible problems caused by this valve.



Found the pictures of the filter and Oil Control valve and the location on the engine they are located in this post
VVT Oil Filter? Poor MPG'S? | Page 3 | PriusChat