Problem car

I don't have much luck with the 01-03 Prius Currently the 01 Prius i bought last year with 127k miles on it is not driveable after sinking in nearly $3000 in parts. Battery, inverter, tranny all had been replaced. Long story short i had bunch of codes but now battery code is gone, inverter code is gone, tranny still some kind of sensor code issue that i am unable to figure out. The tranny had been replaced 3 times that is 6 times in and out and I did the work. It was not fun since bleeding the air out of the coolant was the hard, tedious process. Coolant runs through the tranny to cool electrical motor, generator, etc... in case you don't know!

I am frustrated with this car as it sat in the gargage taking place and not driveable for a year now. There is time i feel like putting gas over it and burn it up to vent off my frustration

Back to reality i have to get this car fixes. Please help someone:mod:
Thank you for your help in advance.

 

You told me about the 12v battery on the 03. This one is 01 with bad battery 12V i recollect. I need to check to make sure the battery is good first then i see it will fix the problem. If there is code i will scan it and report back to you. The 01 is a pain in the rear sucking out $3k from me since last year and all my time and labor fixing number of thing and it had been sitting in my garage for a year now. It is time to fix it or trash it and get this car out of my system. Thank you for your help in advance. I felt a relief that there are helps out there and i found it on this forum

 

Bob,

I hooked up a good 12v battery to the 01 today and consistently had code P3120 on scanner (see attachment). I pulled all and current after clearing each time and it is the same thing P3120.

Another thing is this 12V was disconnected for awhile. Upon starting up with good 12V source (using jump start hooking up to existing battery in parallel) today it ran with no code for about 10 min then shut down. Restart code keeps coming back and clearing at this point does not clear both EL and monitor panel off. I want to work on one at a time so i will leave the 03 code out for now.

What do you think i should do next?

 

Yep that makes sense but you see i already shot an arrow i have to follow. Too late not to finish it especially when i am so close. Once code left.

 

Bob,

The code had been changed! At this point consistently P3120 with fresh good 12V source. Now that is the ECU but i understand i can't swap between year. I currently have two ECU from different year when i was working on this car i had to buy. Unfortunately i can't return them now i am stuck with them already paid I found out the hard way by sticking a different year in the 01 it will lit up just fine but will not start up and run. I swapped with the 02,03 all same symptom, no start but panel will lit up.

I recollect this is the only thing that is not replaced on this car. So far battery pack, inverter, transmission all were replaced. I had this sucker since last year August/08. Lord what a nightmare with this Prius.

I cross my finger i am out of the blue with the tranny. Not sure i want to towe this sucker 85 miles to Berkeley to have troubleshoot just to find out ECU needs to be replaced then i have to deal with shop charge and towing expense. I don't think there is anything on this Prius on the hybrid side that i have not replaced beside the ECU. I recollected last year when i bought the car (long story why i bought it and yes you can say stupid me)I took the cover off the inverter lo and behold i found nuts, bolt loosely lying inside:mod: Some body had f. around with this car and dumped it on me. Monkey repair that what it was.

If i can confirm it is the ecu with a lot more certain with the P3120 code I can order another ECU from LKQ (commercial source that i used when i was a used car dealer) I dealt with this source for the $3k i spent last year on this car so hopefully they allow me to return the ECU if that does not fix it.

I did not know about this forum last year when i encountered this problem. I bought and sold about 6 01-03 Priuses and 4 were lemons. The 01, 03 currently are the worst. One was tranny, the other one was the inverter. 2 others i got lucky. What a pain with first generation Prius

 

On the subject of towing simplest, fastest, easiest is the tow dolly. Just drive the front wheel on, chain it down then you are done. I am not too sure about flat towing as heck no i want no more new problem. I pulled the tranny out too many times to know that it is one heck complicated and heavy part with full of electronic, motor, sensor, generator, CVT in there. The drives shafts attach to the tranny and who knows exactly what is happening with the car going at high way speed. I just want the darn car fixes. I want no more new problem

Prius is modular built i just lack the info. as i have no problem working on it myself. You give me the brain power i can fix it. I can feel i am close to nailing this sucker fix

 

It can't be! The tranny had been replaced 3 times already????

Yes I am more than frustrated! I keep it simple and short. I have a code P3120 on the 01 Prius.

 

Thank you Bob for your info. No i don't have any rats in my garage to eat up the wire. This is what i remember. Last year when i was working removing the tranny i had forgotten the sensor wires to the MG2 attached so as when i couldn't remove it i found out the connector had been stretched quite a bit at the MG2 section. This is the third tranny. it could not have been three in a row. I am not sure the Autoenginuity i have can scan subcode but i think i need to chase wire point by point between the MG2 sensor and the ECU. Can you provide the diagram point to point for that? I am going to ohm it out one by one and flex the wires to see if i have a break somewhere.

One code left please God and Prius forum help me to alleviate my pain to get this headache Prius fixes

 

Trust me I am beyond frustration with the 01 and 03 Prius at this point. See the attachments those transmissions i ended up with on the side of my house. I can't recollect which one is which but one of it came from the 01 and various return exchange and other Prius year i had I ended up with that collection. After these two fix there will be no more first gen. model for me and unfortunately that is since i became fairly an expert at it.

 

Those trannies weight a ton! They are heavyyyyyyy! 3x means 6 times in and out on the same car. LKQ kept sending me bad tranny but after the first one i paid extra for labor warranty so i got some money back. That helped! Actually the tranny was not too bad once i got a hang of it just a lot of labor removing various parts. The air bleeding is tedious and time consuming but i never said it was easier than the tranny work. What said was the Toyota procedure was hardas hell so i came up with way for half a time. Worked on 3 Preius before so i knew i got it right as as beeding the air goes.

I got the wiring print out from Toyota dealer where i took the car there twice to have it scanned. Just now i recheck the wiring and it is definitely okay. I am suspecting the ECM. Read my post to Bob Wilson as i describe in detail of what i found today.

Oh i know i am on the right track all right as there is nothing else. I had replaced and cleared all codes for battery pack, inverter, now it is still the transaxle left but i have the P3120 with ECM module not the transaxle itself on my scanner. It is time to ask Bob further. If you think about it that is very much it for the hybrid portion of this car battery pack, inverter, transaxle, ECM. These are the main 4 main modules of the Prius I bet it also applies to the 2nd and 3rd gen. with some minor change.

Yep you were right i have a story to the rusty disc and bearing axle. Those came from the 98 Mercedes Benz E300 Turbo Diesel i bought and had it shipped from the East coast to California. Long story short i had a dealer that lied to me and sold it to me online. I ended up spendng 6 months fixing that car with the rear axle noise and 50% electrical problem not working. Yep i work on diesel too Mercedes and VW TDI'S. I bought and sold many VW Jetta, Beetle, Golf TDI'S and only a couple Mercedes diesel when i still was a dealer this year. I just folded up the business this month as i plan to move out of Ca by the end of this year 2009.

Get to go to ask Bob about the Prius. Do you have any expertise you can help me with this 01? I still have the 03 Prius with even more codes than this one. One at a time at this point!

 

Bob,

I went to check the wiring on the sensor today between the MG2 and the ECM. Wiring checked out okay with the the one that has 2 wires red/white and gray on it. I have noticed this pattern.

Upon clearing the code and restart the car it ran fine with no code for about 5 minutes. After that code P3120 popped back on. My scanner keeps showing P3120 with ECM module showing when i click on the + on the scanner. I repeated the whole procedure and still same code. I had replaced everything else on this car except this thing. Is it safe to presume it is the ECM to be replaced? See attachment for the different ECM that i have. I notate on there so you know which one does what.

I am tempting to swap with the 03 that i have but hold off until i have more info. I got a feeling it will do the same thing lit up the console but will not start the engine! That 03 Prius has problem with multiple codes at this point. I am trying to concentrate getting the 01 fixes first.

What do you think before i order the correct ECM for this model year? More money spending on this car but I am very close to fixing it. I want to finish it.

By the way this it not related to this issue but I finally took heart to take apart completely the battery pack of this car i replaced last year. I was irritating to see it sitting in my garage with the car still unrepair. See pictures. I had 3 weak cells and found a way to charge individual cell with radio control car battery charger. A bit too late had i known this info. last year i could had gone ahead and did this way instead of spending $1000 for a used battery pack. I am selling good individual cell and can show anyone how to take them apart and fix or replace bad subpack battery instead of the whole thing. Anyone interested let me know. Will save some big bucks if you have a battery pack for sure.