The Nissan Leaf features an ‘electrically-driven intelligent brake control module’. Simply put, this is an electrically-assisted brake master cylinder rather than a vacuum-assisted brake master cylinder as found on a traditional car with an internal combustion engine.
The Leaf’s brake ‘booster’ features it’s own integral control unit which interacts with other control units in the vehicle. It has the ability to command light braking requirements to be performed through regenerative braking using the traction motor only or by a combination of this and the hydraulic brakes.
Nissan has released many firmware updates for the electrically-driven intelligent brake control module in different models of the Nissan Leaf. Some of these updates relate to improved performance and others to safety. Unfortunately, in New Zealand the majority of these updates have not been made available by Nissan New Zealand to their franchised dealers.
We are now aware of several cases in New Zealand of a brake system failure occurring on AZE0-1xxxxx (2014/2015MY) Leafs which were running obsolete firmware in their brake control module at the time of failure. Further details on this issue are available here.
Fortunately, in New Zealand AZE0-2xxxxx cars do not seem to be as as represented in the number of reported failures, however we are aware of a 2016 Leaf overseas that suffered a brake system failure with the early obsolete firmware. The local Nissan dealer that was involved was instructed by Nissan head office to update the firmware in the brake control module to resolve the issue.
One reason why AZE0-2 Leafs seem less prone to braking system failure may be because all Japanese Leafs built after February 2016 already have received the latest firmware update during production, so only cars from the first three months of production have the early firmware. This is in contrast to earlier model Leafs where the original production firmware is obsolete in every case. Only Japanese AZE0-2xxxxx vehicles from December 2015 to February 2016 will require an update to bring them up to the latest version. For UK models, the changeover point to the current firmware version was later in 2016.
We recommend that anyone with an Leaf running the early firmware to have the relevant brake update performed if it is available to them. The graphic below shows the firmware versions to check if a car requires an update or not. This information is available on many diagnostics tools including the Pro version of LeafSpy.
Similarly, in UK spec cars of the same era, the original firmware version is 4NR0A which is updated to 4NR0C.
We already have the ability to perform these updates, but we take no satisfaction in knowing that Nissan NZ has not enabled their network of dealers to do this and they have indicated that they have no intention of doing so. As a result, we will continue working to make these brake updates as accessible as possible for those in NZ that want them.
Please feel free to contact us if you would like to discuss this issue further.