Frankenstein GEN 1 2002 prius code P3191 P0141 P0125 and power steering shake

Story of the CAR: This is my first time ever owning a prius or hybrid vehicle. Since gasoline is on the rise and my commute to work is longer than most i thought it would be a good idea to get a fuel efficient vehicle and save some green. I found a old broken prius on craigslist. Previous owner said someone stole the catalytic converter and right away had a straight pipe welded in the area of where the cat use to be. Then drove it and the vehicle over heated and shut off. Found out that when the person stole the catalytic converter they jacked the vehicle up by the radiator and put a hole in the radiator. He brought it to a toyota dealer and they said the gasoline engine was detonated and needs a new engine. So i picked the vehicle up for $500 thinking i will just replace the gasoline engine for a couple hundred dollars and a weekend of wrenching in the garage. My thought was since he was driving it before seizing the engine everything else was in good working condition. So i purchased a used junk yard engine $200 and replaced the gasoline engine one weekend in the garage by myself. Should of had someone help me because pulling the engine off the trans and putting it back on by yourself is no fun task. I was able to disconnect the gasoline engine and pull just the gas engine out of the top of the vehicle many online say it needs to come out the bottom. After getting the gasoline engine in, new radiator, hooking up all the sensors, and filling with fluids i was eager to see if it started. NOPE did not start, tested the hybrid traction battery and was testing at 60v with dr prius app. I am guessing the vehicle sat off for around 6 months from when the engine blew to when i got a new engine in. So i searched locally for a hybrid battery for weeks and finally found someone selling a used old but good condition gen 1 battery for $600. Swapped the hybrid battery out and now the moment of truth, turned the key and it fired right up. No engine lights on and running good. I let it get up to normal temp around 190 degrees to burp and get the air bubble out of the coolant. Vehicle is idling good, shifting good, and blowing hot air. Now time to take it out for a test drive. I go to reverse and the steering wheel starts shaking like crazy, i panic not knowing whats happening. After searching online it appears the gen 1s are notorious for electric power steering problems. So i continue on down the road and after one block it shuts off and will not go faster than about 10mph. So i pull over scan the codes and see code P3191 P0141 P0125 so i clear the fault codes and vehicle starts up and runs just fine so i take it out on the highway and runs great for the next 30 miles, codes P3191 P0141 P0125 appeared again but did not affect driving ability. I let the vehicle sit for 8 hours and then decided to take it out again. I started the vehicle it started great and ran after one minute it died. So i started it again and it ran/drove good for the next 30 minutes. So i am looking for suggestions on how to fix the following issues listed below.

Frankenstein replaced parts: (trying to keep this vehicle build under $1500 total)

• Vehicle $500
• Junk yard gasoline engine $200
• Used hybrid traction battery $600
• New engine coolant temp sensor ECT $20
• Gasoline engine radiator $65
• New spark plugs NGK $25
• Fluids $65

Problems car is having:

1. Steering wheel shakes when backing up at low speeds
2. Car dies shortly after you start the vehicle
3. Fault codes P3191, P0141, P0125

Questions i have:

• Is it just annoying but safe to drive the vehicle with the power steering acting up? It appears to be a big pain to replace the power steering on these vehicles so if there is no safety concerns with the malfunctioning power steering i will probably just drive it as is. If i unplug the power steering will it still operate, just be hard to turn like it had no power steering?

• Should i change the transmission fluid now? If so what fluid do you suggest putting back in ATF WS or ATF IV?

• Why does the car die shortly after you start it? Is code P3191 indicating it could need the new ECU part# 8966147054? if i find a used ecu on ebay can i just swap it out or do i need to program the ecu to the vehicles vin#?

• Code P0125 says insufficient coolant temperature for closed loop fuel control. Does this indicate i have a bad thermostat on the gasoline engine? or is this code coming up because the catalytic converter is missing and the second 02 sensor downstream is missing?

• Code P0141 is 02 sensor heater circuit (bank 1 sensor 2) i would assume this code is coming up because the catalytic converter and the second 02 sensor is missing.

I appreciate anyone that reads this entire thread and i truly appreciate any help, suggestions, or feedback on how i can solve the issues with Frankenstein

 

ya usually start the drive reversing out of the driveway at home or out of the parking spot at work so you might be correct thats why i only notice it in reverse. Seems to be only when the steering wheel is far to the left.

ok thanks i will poke around and see if there is a trans dip stick and check the condition of the fluid. If not i will probably change the trans fluid after a couple weeks if the vehicle continues to run good.

 

Ya never experienced a shake like that in the steering wheel, i pooped the first time it happened. Had no clue what was going on but after digging online it made sense since the power steering is electrical and not like a standard power steering pump i would of seen before. Replacing the power steering looks like a huge job and i dont want to really spend any more money on this old antique so i will drive it a few more days or weeks and if it acts up more i will just unplug it.

If i unplug it, is there two connectors i am looking for? should i just unplug them and leave the connectors or do i need to water proof the connectors? Will the ecu act up or go in limp mode if i unplug the power steering? Thanks for any help, i am learning a lot about these unique cars. I said from here on out the only car i will be purchasing is a prius because i know how to fix them now,

 

ok so i am looking for something with the part number 89650-47190 on it that looks like the photo and its located behind the glove box. If i unplug all wires going to it then the power steering will be only manual and no electric assist. i will do this and see if the car throws any codes or what happens. Hopefully all is good and i can move on. thanks for the help

 

ok so after driving the vehicle a couple hundred miles in a few days here is an update on the vehicle. The vehicle has no problem starting or staying running no more P3191 code. I did nothing it just went away and starting running great. Maybe Frankenstein just needed a couple days to wake up from the dead. I am still throwing Fault codes P0141 and P0125. P0141 because the second o2 and cat are missing. P0125 insufficient coolant temperature i think is because its been cold out 10-20 degrees and the vehicle does not warm up fast enough so the ecu throws a code? Vehicle runs around 190 degrees and has super hot heat. I am going to replace the thermostat soon to see if that helps it warm up quicker and if not then i will just leave that code alone and forget about it. The power steering only shakes when turning tight left at very low speeds. I am going to leave it for now but if it becomes an issue i will just unplug the power steering computer behind the glove box, this will disable the electric power steering but should still be manageable to drive.

The last question i have is when its very cold out and i start the vehicle the coolant light comes on the dash and once its warm the coolant light goes off. Is this just telling me the vehicle is cold and once the light goes off its at operating temperature?

I am very happy i got this vehicle running as it will help me with gas mileage to and from work. Thanks to everyone that chimed in and taught me some new things about these unique creatures. I am a prius fan now

 

perfect ya its the blue one i was seeing only come on when cold. So i assumed it was indicating the engine is cold and not to operating temp yet. The only reason i thought this is because other toyota vehicles i have owned before always had a cold light of some sort. So thats a relief to know its nothing serious

 

what sensor do you suggest is making P0125 trigger?

my understanding is Code P0125 says insufficient coolant temperature for closed loop fuel control. This would indicate the temperature of the coolant is not at the proper temp for closed loop?

 

So the code P0125 is indicating something in the fuel delivery is not correct? either o2 sensor number one is faulty or some sort of fuel delivery method is not working correctly like MAF, fuel injector, throttle body, etc. ?