Software Problem Can Damage Hybrid System in Recalled Prius Vehicles, Causing Stall

software updates are needed even if previously repaired under older recalls

Software Problem Can Damage Hybrid System in Recalled Prius Vehicles, Causing Stall
Image: Toyota
October 15, 2018

Toyota is recalling the 2010-2014 Toyota Prius and Prius V vehicles. In about 807,329 of these vehicles, excessive voltage in the Intelligent Power Module (IPM) within the inverter may cause the hybrid system to shut down, causing the vehicle to stall while being driven.

What's the problem?

In the affected vehicles, certain software used to control the IPM within the inverter assembly, a part of the vehicle's hybrid system, can cause stress to specific transistors under high-load driving, such as accelerating. Over time, this can damage the transistors, illuminating various warning lights and displaying a warning message on the instrument panel. In some cases, the motor/generator Electronic Control Unit (ECU) can reset. Additionally, if a specific transistor fails in a certain way during a high-load driving condition, such as hard acceleration, an abnormally high voltage can be generated.
If the ECU resets or an abnormally high voltage is generated, there is the possibility that the hybrid system could shut down instead of entering a failsafe driving mode, increasing the risk of a crash.

The software updates in this recall are needed even if the vehicle had the software previously updated under recalls 14V-053 or 15V-449.

Other Toyota or Lexus vehicles do not use the same hybrid control ECU and software as the involved vehicles or had improved software as original equipment to reduce thermal stress to certain hybrid inverter components as described in recalls 14V-053 and 15V-449.

What happens next?

Toyota will notify owners and dealers will update software as necessary free of charge. Interim notices informing owners of the safety risk are expected to begin October 22, 2018. Owners will receive a second notice when the remedy becomes available.

Owners may contact Toyota customer service at (888) 270-9371. Toyota's number for this recall is J0V.

Extended Warranty and Reimbursement

To support increased customer satisfaction, as a separate Consumer Support Program previously initiated, the dealer will repair or replace the inverter assembly (depending on the failure diagnosis) if an owner experiences a hybrid inverter component failure related to the conditions described above, at no charge up to 15 years from the date of first use of the vehicle with no mileage restrictions. In addition, the new software for the hybrid control ECUs will support a further enhancement to the failsafe driving modes to provide for increased available speed and range under more circumstances in the event of a failure requiring failsafe driving.

An owner letter will instruct vehicle owners who have paid to have this condition remedied prior to this campaign to seek reimbursement pursuant to Toyota's General Reimbursement Plan.