The earliest examples of the Nissan Leafs (ZE0) were manufactured at the end of 2010.  These continued to be built until late in 2012 when a significant revision was released (AZE0).  It appears that Nissan (or their supplier Nichicon) struggled with getting the on-board chargers perfected on the ZE0 models.  There were at least 5 hardware revisions as well as software (firmware) updates for almost every hardware version as shown below.  The current charger version in any car can be checked using tools like LeafSpy Pro.  We recommend that on-board chargers are updated to the latest firmware version that is available.

Earlier hardware versions in particular seem to be more likely to develop a somewhat rare fault where the quick charge port will continue to work but the car will not charge on the normal charge port.  If a good EVSE is being used, then it will report a fault that indicates that it has failed it’s ‘diode check’ and therefore not allowed the car to charge. Often the car will not register any fault codes.

In the previous cases of this fault that we are aware of, the solution was always to replace the entire on-board charger.  However, when we were asked to diagnose and repair a 2011 Nissan Leaf that had this same charging fault we decided to take a look at what was actually failing in these chargers.  As it turned out, it was able to be fixed for less than a dollar worth of parts.   The charger still needed to be completely removed from the vehicle for the repair, but that would needed to be done for a charger replacement anyway.

We decided to share our findings to help out any other Leaf owners from around the world that might run into this same problem – check out the video in the sidebar of this article.  We recommend that the charger is only removed by someone trained to work on electric vehicles and the component replacement is only completed by an electronics repair specialist with the right skills and equipment to replace surface mount components.  We are happy to complete this work or advise people who have questions on this repair.