Here we go again…. GM is beginning to notify existing owners of 2018 and 2017 Bolt EVs that they should bring their cars into the dealer for a software update that will improve the way the car behaves in the unlikely case that a battery cell begins to go bad.
The company had previously issued a dealer-installable update for 2017 Bolt EVs and many owners brought their cars in for that update in recent weeks. That update improved the warning to the driver giving them a little more advanced notice before the car was forced to quickly reduce power and then shutdown the propulsion system due to a failing battery cell.
The new update is for both 2018 and all 2017 Bolt EVs even if a 2017 model already had the previous update installed.
For 2017 Bolt EV owners who already had the previous update installed by a dealer, the latest update improves the displayed driving range estimate to take better account of any weak battery cell that may be detected. As an example, some Bolt EV owners with failing cells have reported seeing their estimated driving range suddenly drop from 100 miles to a much lower range.
With the new software, a weak or failing cell detected by the car will result in a more realistic driving range estimate even when the battery pack is fully charged and large sudden drops in predicted range are less likely to occur. The newest update also includes various other drivetrain control improvements that a driver would not normally be directly aware of.
Owners of 2018 Bolt EVs were not notified to receive the previous dealer-installed update because their cars are very unlikely to develop failing battery cells so there was less urgency to apply that update, according to GM spokesman Chris Bonelli. GM decided that 2018 Bolts could wait until the newest update was ready to release.
Aside from these updates, GM continues to use the OnStar communications module in every Bolt EV to periodically check the battery cells in cars in order to detect any developing cell failures before the car shows outward symptoms. GM will notify the vehicle owner if a bad cell is detected and schedule a battery replacement under warranty. The company has said that owners are now very likely to be notified of any developing problem before ever experiencing a reduced propulsion event or unexpected vehicle shutdown.
The exact number of cars that have developed bad cells has not been stated publicly but many cars are believed to come from the first months of early production although some later, mostly 2017 model year cars, have also experienced bad cells. The company says only a “small percentage” of cars will develop a prematurely weakening cell.
GM released the following official statement about the new update:
“General Motors is looking at the entire Bolt EV fleet to ensure everyone has the most updated software available. Through letters we are asking all Bolt EV customers to schedule a service appointment to receive the latest software, including the 2017 owners who received the previously released software calibration. In the event of a cell low voltage condition, this new software increases the accuracy of the range estimation, in addition to providing more warning at low states of charge. We understand this is an inconvenience for some customers to service their vehicles again so soon. However, we want to give our customers the most updated software as soon as it’s available.”