Thursday, March 21, 2013

Failure Analysis

The above image shows a failure of the highest degree when it comes to Hybrid Electric Vehicles. The dreaded P3009 (High Voltage Leak Detected) trouble code could be attributed to several problems. Battery modules leaking small amounts of electrolyte, problems within the air conditioning compressor and a few others come to mind. Burned out stator windings in a 2001-2003 Toyota Prius drive unit are a distinct possibility as the miles roll up. A Prius model year 2004 or newer uses a boost converter to increase voltage to MG2, which is the main drive motor within the transaxle. Higher voltage means that less amperage is needed to drive the wheels. Less amperage means less heat is generated within the motor, leading to longer life. Click on the picture for a closer view; you will see that the windings were hot enough to burn off the insulating coating that prevents the individual wires from conducting current amongst each other. This condition seems to be less common to Prius owners who have regular maintenance performed at the recommended intervals. The transmission fluid that Toyota recommends has been improved since the original Gen 1 Prius was released. The newer fluid is better at providing some insulating qualities that the earlier fluid lacked. Repairs for this condition involve either new stator assembly from Toyota (figure on spending around $2500.00 parts & labor) or replacing the entire transaxle with a used unit ($1500.00 parts and labor). There is no way to predict whether a used unit is "near failure" without partial disassembly, and warranties on used parts are often very short and may not include labor.