Any ideas? P3009 and info code 526 overheating

A few questions:

Odometer reading?
Accident history?
Do you know which coolant pump had been replaced: the electric inverter coolant pump, the mechanical engine coolant pump powered by the serpentine belt, or the electric engine coolant heat recovery canister pump?
What do you need to do to make the inverter overheat?

DTC P3009 means a high voltage ground fault. That associated with inverter overheating implies that the inverter needs to be replaced, but further investigation would be required to determine exactly where the ground fault is located - maybe your car has two separate problems.

 

Boiling? Perhaps there is still air trapped in the system? The air hasn't been fully bled out...

 

Does it "boil" when you do a cold-start of the car? Is the fluid level dropping slowly?

 

Did you tell the service writer that the car has to be driven for an hour before the inverter will overheat? Does the car overheat only when driven on the freeway or will it also overheat when driven around town?

Make the car READY and turn on the air conditioning. Set the thermostat temp low enough so that the AC compressor is running. Go to the front of the car and note the radiator fans running. Are they blowing air towards the front of the car, or sucking air from the front of the car? The latter is correct. If the former, this would explain overheating when the car is driven at speed.

Make the car IG-ON (where the instrument panel warning lights are all on, and the car is not READY.) Open the hood and find the inverter coolant pump which is behind the driver's side headlamp assembly. Listen to the pump. It should sound like an aquarium pump and you should not hear bubbles.

If you don't hear the pump run, or if there is air in the system, that is why the inverter is overheating. If you do hear the pump running properly, then maybe there is a clog in the inverter cooling channels.

 

Please check your radiator fans again. Your message above is evidence that the fans are blowing air at the radiator. The air from the engine compartment is heated, then blows past the outside air temp sensor which is located in front of the radiator. This causes the erroneous readings that you indicated above.

Several other posters have reported an overheating problem similar to yours. Usually their vehicle has been in a front-end accident. The radiator fans are reversed during reassembly.

Note that the fan blade count differs when looking at the two fans, 5 blades vs. 7. Also note that the fans are supposed to spin in opposite directions. So, if the blades are swapped then they will blow air in the incorrect direction.

It sounds like the inverter coolant pump is working, based upon your description of the sound that it produces.

 

They only come on when needed, iirc based on coolant temperature.

 

If you turn on the AC and set the cabin temp low enough so that the AC compressor is running, then at least one of the two radiator fans should turn on. You might try carefully placing your hand in the space between the radiator fan and the engine, and see if you can feel air being blown at your hand or not.

When the engine coolant temp rises high enough, then the other radiator fan should turn on.

 

Yes, this makes sense. The Prius air conditioner compressor is powered by an electric motor that receives high voltage AC from the inverter. The compressor oil needs to be a special non-conductive type because the motor is in contact with the oil. If normal oil is used, that will cause a high voltage ground fault in the motor, and the compressor will need to be replaced, which is probably a $2K repair.

I suppose one way to test this would be to leave the air conditioner off and drive around to see if DTC P3009 appears. If it doesn't appear after a reasonable time, then turn on the AC and see if that code is logged.

Also, the "regional guy" should have a megger, which is an ohmmeter that uses high voltage. This can be used to identify the component causing the ground fault.

 

OK, I hope that it only costs $150. Usually the AC compressor (not just the condenser) will need to be replaced if the wrong compressor oil is used.

See Automotive Training and Resource Site
and look for Hybrid18 Other Systems.pdf

Also, the following text is in the Toyota repair manual regarding DTC P3009:

"NOTICE:

Electrical insulation performance may decrease significantly if even a small amount of oil other than ND-OIL 11 is used (or enters) in the refrigeration cycle, causing the DTC to be output.

If other is accidentally used and a DTC is output, collect the oil in the refrigeration cycle into the compressor and replace it with ND-OIL 11 to increase the ND-OIL 11 ration amount.

Replace the main components (evaporator, condenser, and compressor) if a large amount of oil other than ND-OIL 11 enters the system. Failing to do so may cause electrical insulation performance to remain low, causing the DTC to be output."

 

Hi Michele,

If the compressor oil was the correct type but low, then your car would not have logged DTC P3009 unless some other hybrid vehicle component (unrelated to the air conditioner) was responsible for the high voltage ground fault.

I also hope that your bill is $150. However don't be too surprised if it grows to a four-digit amount. Good luck.

Also, I suggest that you ask the service writer to ask the tech to check the radiator fans while the car is there. Let them know that you've noticed the ambient air temp gauge reading is much higher than normal, which causes you to be concerned that the radiator fans are blowing hot air from the engine compartment and radiator towards the air temp sensor mounted in front of the radiator, which is the wrong air flow direction.