Please Help!!!!!

A generic OBD-II code scanner has little chance of picking up DTC logged by the various Prius ECUs. This is why you are not finding any DTCs.

My guess, if you do not hear any drivetrain noise, is that your inverter coolant pump has failed. When the car is IG-ON (not READY), listen for the pump running. It is located near the driver's headlight. It sounds like an aquarium pump. You should not hear any air in the fluid.

Also look at the inverter coolant reservoir. When the pump is running, you should see a step in the fluid level where the front is higher than the rest of the fluid.

When the pump fails, this allows the inverter to overheat. Once it overheats, it will start to reduce inverter operation which causes the warning lights and driveability issues that you noted.

The check engine light would come on if there was an engine ECU DTC, so since this light stays off this is evidence that the problem is with either the transaxle or the inverter. Since you are not reporting unusual drivetrain noise, I would say the inverter is the likely problem.

 

First I would recommend going to the Toyota service center and find out what it will cost to have your error codes read out. If you can, ask them to also read out the battery module voltages and temperatures and give you a written copy of the codes. This will allow us to diagnose your problem.

Without the codes, the ambiguity group includes:

• impending traction battery failure - Do you hear the battery fan running when you park? Does it seem to happen after coming down a large hill or braking?
• 'big hand' from a failing accelerator pedal (known problem of 2001 Prius) -- can happen anywhere.

I see you live in Colorado, what part? If you are close to someone with a Graham scanner, they could read out your codes and possibly save the trip to Toyota.

GOOD LUCK!
Bob Wilson

 

This question presupposes that the inverter coolant pump is functioning. Can you hear the motor running? Do you hear air in the system?

To answer your question, there won't be much pressure coming from the bleed ports.

Bleeding the inverter coolant system is not an easy job. I strongly suggest that you subscribe to techinfo.toyota.com and obtain the relevant repair manual pages for your vehicle to improve your chances of successfully completing the task.

Even after you have access to the repair manual pages, you will probably find that the suggested bleed process yields slow progress. After you reach a point where no further progress seems to be made but you still have air in the system, you may find it useful to drive around the block and then continue working on getting the air out.

If you are planning to drain and refill the coolant, I suggest that you use either of the Toyota coolants: either Super Long Life Coolant with the pink color or Long Life Coolant with the red color. SLLC is premixed with distilled water and is relatively expensive.

When draining the coolant, make sure that you do not drain the transaxle ATF by mistake. The coolant drain is on the bottom of the transaxle between the engine and the transaxle black drain pan, while the transaxle ATF drain is on the transaxle drain pan.

Good luck.

 

In other words: take it to a dealer now, before you burn up the inverter. Don't turn a $200 job into a $2000 job.