TOYOTA PRIUS READY SIGNAL BUT HAS NO POWER ON DRIVE OR REVERSE!,HELP

The Hayes manual is a light-weight version of Volume 2 that deals with mechanical repairs. Their diagnostic section is unusually light and they really don't have a clue as to how our Prius works. I know because I bought one and compared to the Toyota shop manuals, it is not very detailed and lacks insights.

Bob Wilson

 

1. I suggest you access techinfo.toyota.com for factory repair manual information including interpretation of the various DTC.

2. If the replacement inverter works and was correctlly installed then it is reasonable that the transaxle might be at fault given the continued presence of P3125.

3. I am not aware of any "rebuild" facility available for the transaxle. You would probably have to purchase a used unit from a salvage yard.

4. What prevents you from reinstalling the engine MAF sensor and any other missing parts?

5. Was this car in a front end accident?

 

If the half shafts are removed from the transaxle, then you have no ATF fluid in the transaxle. If you have no ATF fluid in the transaxle, then you don't want the engine to turn on, because in order for it to do so, MG1 within the transaxle has to spin up.

If MG1 spins up without ATF fluid, that will probably damage the power split device within the transaxle (similar in operation to a differential, but its purpose is to allow power to flow between the engine, MG1 and MG2.)

If the car shows READY and no warning lights appear, then there is some hope that the car might start. I suggest that you fully assemble the remaining missing parts and see if the car will start. If it doesn't start and there are no DTC logged, then I suggest you have the car towed to your local Toyota dealer for a diagnosis. Good luck.

 

I think you should seek professional assistance by having your car towed to your local Toyota dealer or hybrid independent specialist.

 

You might contact these folks and ask about independent mechanics:
Auto Careers Development Center - Hybrid and Electric Vehicle Repair Training

They have a 'shop finder' page but it is not always current:
Hybrid Shop Finder | Auto Career Development Center

I would recommend giving them a phone call for their most recent and current recommendations. BTW, they also have video training and the one I took was pretty good. It doesn't hurt to ask.

As for your current project car, the codes posted are pointing at the engine ECU and possibly a failed, DC-to-DC inverter. This is the part that generates 13.8-13.9V needed to recharge the 12V battery.

Bob Wilson

 

I don't think there is anything 'magic' about the Prius that prevents anyone with what I consider to be ordinary technical skills and the good tools and books can't figure out. But Haynes is at best a 'parts to swap' manual and exceptionally light on the diagnostic aspects. Swapping parts, especially with the Prius, is an especially poor approach. And this is a computer operated car, we just tell the computers what we want to do and they try to respond. When they can't, they are able to give error codes and diagnostic information.

With a Prius-aware scanner and the Toyota shop manuals, anyone who understands how to read a volt meter and handle a torque wrench has a good chance of keeping them running. Over the 12 years of NHW11s in North America, pioneers (who were my teachers) taught us about the obscure aspects not covered in even the Toyota manuals. But that is why some of us hang here and the other places mentioned in the sticky.

We're willing to share our expertise and even explain the why behind what we suggested. Consider how much we're charging for this advice . . . the alternative is to ask Mr Google . . .

Your codes point to the engine ECU and this is rare but not unknown. But the first step is to fault-isolate the problems and share what you learn. Please, start with diagnosis and only swap parts as empirical data identifies parts that need replacing. Besides, the tools you need for proper diagnosis are really neat (Ok, I'm an engineer and few understand how we think.)

Bob Wilson

 

I'm sorry to hear this. The over-the-counter OBD scanners are able to read out a few codes but the details needed are not there. But Prius-aware scanners that I have tradeoffs:

1. Scangauge II ($150) - to make it Prius aware, you'll need to add XGAUGE definitions. The sticky has them but it also needs a 'pig-tail' or the special ISO-9141/KWP2000 only cable. It can also be used to improve driving technique and learn more about this car.
2. AutoEnginuity ($500) - requires your laptop but is a full-up, diagnostic package. I had one until a virus destroyed my virtual PC image. It works and there is support, a solid product but not something to use in general driving.
3. miniVCI ($35) - a Chinese hack of the Techstream-Lite, their "XHorse" retailer is the only one I've to work on both my wife's ZVW30 and our NHW11. It took almost two weeks to arrive and requires your laptop.

Ok, let's start with basics:

1. What is the 12V battery voltage now? It may need to be recharged.
2. Absence of codes is bad suggesting the ODB buss may be 'broken'. We'll need to fault isolate once we know the 12V battery is OK. I'll try to post some suggestions but the team may have some suggestions.
3. Search on "Chapman" and "code flash" - he has done some original work on how to jumper the OBD connector to get the ECUs to flash their error codes.

Later tonight,
Bob Wilson

 

After swapping the inverter from your Dad's car? Sounds like the one removed is bad.

What are you using for coolant? Most of us find bleeding the inverter loop a pain.

Again, this is why the Toyota Diagnostic Manual, Volume 1, is so useful:

• P0500 Vehicle Speed Sensor Malfunction - "During vehicle is being driven, no vehicle speed sensor signal to ECM", DI-108 to DI-109
  • Combination meter
  • Skid Control ECU
  • Open or short in vehicle speed sensor circuit
  • Vehicle speed sensor (one on each wheel)
  • ECM (engine control module, aka. engine ECU)
• P3120 HV Transaxle Malfunction - "The HV ECU checks the energy balance and detects abnormality if the magnetism of the motor or generator greatly decreases.", DI-257 to DI-270
  • 234 INFO code - small reduction in motor magnetism (aka., MG2)
  • 235 INFO code - large motor reduction
    • HV transaxle (motor)
    • System main relay
  • 236 INFO code - small reduction in generator magnetism (aka. MG1)
  • 237 INFO code - large geneator reduction
    • HV transaxle (generator)
    • System main relay
  • 239 INFO code - shaft damaged
  • 240 INFO code - generator locked (if engine runs, not possible)
  • 241 INFO code - torque limiter sliding
  • . . .
  • 260 INFO code - generator temp sensor problem

The "INFO code" tells us what is failing which could be as simple as a loose connection or something worse. This is where a Prius-aware scanner pays for itself. It identifies what to check. Having either the TIS service or Volume 1 of the 2001-03 Diagnostics manual would be the road-map to what is broken.

Bob Wilson