Electric vehicle manufacturers have been grappling with the vexing issue of safety recalls over the past year. Aside from a serious issue facing millions of vehicles with a potential major airbag recall being considered by the National Highway Traffic Safety Administration, various equipment and software update recalls have plagued EV companies.
EV manufacturers have had recalls this year for over-the-air software updates, which Tesla CEO Elon Musk always denies are recalls because they don’t require vehicles to be taken to a dealer for repairs. But Tesla has had actual equipment recalls, such as in March when the NHTSA opened an investigation into 100,000 Tesla 2023 Model Y SUVs over steering wheels coming off while driving.
Tesla and Nissan steering wheels fall off
Nissan had the same problem in February and March when it issued a voluntary safety recall of 1,063 of its 2023 Ariya electric SUVs after discovering a similar problem Tesla was having with missing steering wheel bolts that could cause loss of steering control and an increased risk of a crash. Now Nissan has another problem requiring a recall.
Nissan (NSANY) filed a safety recall report with the National Highway Traffic Safety Administration on 28 September for 9,813 2023 Ariya two- and four-wheel drive electric sport utility vehicles to fix a defective inverter that unexpectedly cuts power to the motor when the inverter software detects a short circuit, resulting in a loss of drive power. An unexpected loss of drive power while driving at high speed can increase the risk of a crash, the report said.
In the affected Ariya EVs, conductive fibre chips from the slip ring assembly of the drive motor can momentarily short-circuit the two slip rings and instantly burn out the fibre chips, causing no damage to any components. Due to the fail-safe protocols, if the inverter detects a momentary overcurrent due to the short circuit, it will reduce the motor torque to protect the internal components of the controller, resulting in a loss of drive power and an “EV System Off” message will be displayed on the dashboard to alert the driver.
Short circuit causes loss of power
If this occurs, torque to the vehicle’s wheels will be cut off until the fail-safe mode is released after the vehicle is switched off and restarted. However, the loss of power could increase the risk of a crash.
Nissan first noticed the problem during a production test in January 2022, when a diagnostic trouble code indicated that a short circuit had occurred inside the vehicle’s engine, but no damage to the engine or any components was observed. Nissan continued to investigate the cause.
In subsequent inspections of Ariya motors and inventory parts from February 2022 to April 2022, Nissan discovered conductive fibrous shavings on a slip ring end in the motor, apparently left over from manufacturing. Nissan determined that the shavings could cause a transient short circuit that triggered the inverter’s fail-safe mode. Later, in December 2022, Nissan received a report from China of a motor shutting down at low speed with an “EV system error” message displayed.
After further investigation, Nissan introduced improved inverter fail-safe control logic into production in April 2023. After receiving three more incidents of motor shut-off between May 2023 and September 2023, the automaker issued a voluntary recall to update inverter/motor control software and improve fail-safe protocols.
Nissan is not aware of any accidents or injuries related to the inverter issue.
The inverter issue only affects 2023 Ariya SUVs manufactured from 17 June 2022 to 19 May 2023 and no other Nissan or Infiniti vehicles due to the unique motor type used on the vehicle, the NHTSA said in a letter to Nissan confirming the recall report.
Nissan notified dealers of the recall on 29 September. Dealers are being instructed to reprogram the inverter to improve fail-safe protocols. Owners of potentially affected vehicles will be notified on 20 October to bring their vehicles to a Nissan dealer for repairs, which will be free of charge as the affected vehicles are covered under warranty.
