NHTSA Preliminary Evaluation PE21005

The Office of Defects Investigation (ODI) opened a Preliminary Evaluation (PE) to understand the contributing factors and frequency of vehicle fires originating from the battery region of the engine compartment in Model Year (MY) 2013-2018 Toyota RAV4 vehicles on 25 February 2021. At the time of opening, ODI attributed eleven allegations and additional EWR events to this PE. PE21005 focused on replacement batteries installed in the subject vehicles. No reported fire event identified in PE21005 involved the originally supplied 12V battery. The reported fires took place in vehicles known to contain aftermarket batteries or whose age exceeded the expected life of the original equipment battery. ODI identified battery dimensioning as it relates to the battery retention system (hold down bracket, radiator support bolt, J-hook, and battery tray) as the main factor set in the contact between the battery hold down bracket contacting the positive terminal of the 12V battery. The subject vehicles carried over the same battery tray and retention system from the prior generation (MY2006 – MY2012) of RAV4 vehicles. However, the subject vehicles were equipped with a dimensionally smaller battery (Group 35) than the prior generation (Group 24F). The smaller- length measurement in the Group 35 battery size in a battery tray originally designed to fit a Group 24F battery contributed to increased potential for battery movement which was exacerbated by the diversity in aftermarket battery configuration and irregularities intrinsic to battery replacement procedures. Battery movement coupled with the proximity of the B+ terminal on the battery and the grounded electrically conductive hold down bracket set the stage for a short to ground leading to an engine stall (if in operation) followed by a vehicle fire. This investigation was not able to classify the installation status, battery size, or cause of every allegation due to the fire event causing damage to the area, inaccessible vehicl