NHTSA Complaint #11557774 — 2013 NISSAN LEAF

The car suddenly lost power during freeway driving. The brake system appeared compromised. Turning off 12v accessories - which includes safety critical functions such as the defrost blower - was necessary to restore functionality. This is caused by a defective DC-DC converter that fails to properly charge the 12V battery, risking and repeatedly causing sudden loss power, loss of braking, and loss of safety critical functions. This is not the result of damage to the DC-DC converter or other such damage. This is proven by the fact that activation of the wipers triggers the DC-DC converter to temporarily raise the charging voltage to a level sufficient to restore power and charge the 12v battery. Due to defective programming of the DC-DC converter, the power provided to the 12v battery and system quickly returns to unsafe low levels. The DC-DC converter has a sense line that senses the voltage of the 12v battery, but the programming of the converter is defective such that it does not actually maintain the battery at a healthy level. This is a commonly reported and discussed issue on Nissan Leaf ownership forums. Reprogramming of the DC-DC converter is necessary, but not available from Nissan. This issue also causes early degradation of 12v batteries, and replacement of the 12v does not cure the issue. The most recent occurrence of loss of power was 11/30/23, but it has happened repeatedly in the past.