Why Toyota halted deliveries of Innova, Hilux and Fortuner

Toyota Kirloskar Motor (TKM) has resumed deliveries for the Innova, Fortuner and the Hilux diesel variants. The global body suspended the shipments of some models including the Hilux truck and Land Cruiser 300 SUV after finding irregularities in certification tests for diesel engines developed by its affiliate, Toyota Industries.

Earlier in January, Toyota Industries Corporation (TICO) received a report from the special investigation committee (chaired by Hiroshi Inoue) that was commissioned to investigate potential irregularities of certification regulations related to inappropriate domestic emissions certification of engines for forklifts and construction machinery. Toyota had commissioned TICO to develop diesel engines for automobiles.

The issue in hand was caused by a software glitch. The power band curve of an engine which shows the power to weight the range of operating speeds under which the engine or motor is able to output the most power contains minor peaks in between. This is because the power from the engine does not remain constant at every given point.

However, the software that Toyota was using had smoothed out the peaks. While it did not affect the end test result, nonetheless it can be termed as faulty because of an unnatural power band curve.