Prius Hybrid Transaxle Repair
Do you have a master warning light on in your Prius? Does your car have a “juddering” feel when you take off from a stop? That’s the big triangle that comes with some kind of a message on the display panel. It looks like this:
If you have this message, and a scan of the codes in the hybrid vehicle computer shows a code P3125, sub code 237,or a code P3009 (High Voltage Leak) Toyota’s diagnosis will almost always be that the transaxle needs to be replaced. On the 2004-2009 Prius, the code will often be P0AA6 (Hybrid Battery Voltage System Isolation Fault) which sounds like a bad battery but it is more often in the transaxle. Often on the 2001-2003 Prius, the charge for this comes close to exceeding the value of the car. If you get this diagnosis, please give us a chance to see if we can save you considerable money by just replacing the electric motor components in your transaxle that have failed. Some pinpoint diagnosis is required and not every transaxle is repairable, but most are. It might be the difference between repairing your car versus junking it.
Our repair reduces the cost by replacing only the electrical components that fail. Below the procedure is outlined.
First, the inverter is removed to gain access to the upper transmission mount
The inverter is the component that fills up about half of the engine compartment under the hood. The unit is cooled by coolant and the same cooling system as the transaxle. The coolant must be drained before removing this component.
Windings and rotor of Motor Generator 2
Here the Toyota Prius transaxle has been lowered enough to remove the back plate. You can see the burnt spots on the windings of the electric motor which in this case caused the high voltage leak code but no other symptoms. This car drove and operated fine but had the master warning light illuminated.
The motor windings and rotor are removed and replaced
This job takes most of a day and costs about $2300 including parts, transmission fluid, coolant, and labor. Success rate so far has been 100%.
The price for the job on a 2nd Generation Prius (2004 to 2009) is a bit higher, but still about 1/2 the cost of a replacement Toyota Prius transmission.
This is a 2006 Prius with just the new rotor installed, waiting for the windings.
The magnets in this motor are very strong. It take two technicians to install the motor windings because the magnets want to pull the rotor back out of the transaxle.
Ready to go back together.
Potential problems with Toyota Prius transmission repair: There are other parts in the Toyota Prius transaxle that may fail. We have had two transaxles that suffered a bearing failure in the planetary gear set after the electric part was replaced. Fixing this requires transmission removal and tear down. Parts are available to fix the failed bearing. The other alternative is installation of a low mileage used Toyota Prius transaxle. Cost for this varies but typically is less than $2000 installed.