Toyota Motor Thailand (TMT) has recalled 18,000 third-generation Prius hybrid cars in the country after its parent company Toyota Motor Corp announced a worldwide recall of 1.9 million vehicles due to a programming glitch in the hybrid system.
The cars are being recalled for reprogramming of the inverter and ECU – the latter particularly for power management control – free of charge. The software update will take about 40 minutes to complete.
According to Toyota, about half of the recalls are in Japan, while more than 700,000 are in North America.
All Prius cars sold in Thailand from November 1, 2010, to January 31, 2014, need to be taken to Toyota service centres for the reprogramming, said TMT senior executive vice president Vudhigorn Suriyachantananont.
He said many Thai customers do not understand the term “recall”, and this could lead to misunderstanding.
“The term ‘recall’ means the company is asking customers to bring in vehicles for inspection or repair at Toyota dealerships free of charge. This shows our responsibility to our vehicles, which reflects our responsibility to customers. It does not mean we are taking the vehicles back,” he said in a TMT statement.
According to the recall announcement, the problem is in the software used to control the boost converter in a module that is part of the hybrid system.
Toyota has identified that there may be an issue concerning the software in the Intelligent Power Module, part of the hybrid system’s inverter assembly. The boost converter is required when driving with a high system load, for example when accelerating hard from a standstill.
According to Toyota, the software setting could lead to higher thermal stress occurring in certain insulated-gate bipolar transistors in the boost converter, which may lead to the transistors deforming or being damaged. Should this happen, warning lights may be illuminated and the car is likely to switch to a “failsafe” operation. It can still be driven, but with reduced power. In limited cases the hybrid system may shut down, causing the vehicle to stop. The driver will not experience any change in the vehicle’s behaviour or performance.
Toyota confirmed that this issue will not occur in other Toyota hybrid vehicles, as these use different transistor structures and control logic.