"The subject vehicles may be equipped with an airbag control module for the supplemental restraint system (SRS ECU) manufactured by ZF-TRW. The ECU receives signals from crash sensors and deploys the airbags and seat belt pretensioners in accordance with design specifications. This ECU contains a model DS84 application-specific integrated circuit (ASIC) which controls the communication of the crash sensor signals, firing commands (i.e., when to deploy the airbag(s) and/or pretensioners), and fault information (e.g., diagnostic trouble codes).
"This ASIC does not have sufficient protection against negative electrical transients that can be generated in certain severe crashes, such as an underride frontal crash where there is a large engine compartment intrusion before a significant deceleration. In these cases, the crash sensor and other powered wiring can be damaged and shorted so as to create a negative electrical transient of sufficient strength and duration to damage the ASIC before the deployment signal is received in the SRS ECU. This can lead to incomplete or nondeployment of the airbags and/or pretensioners. In model year 2014-2019 Corollas, one potential mechanism contributing to the short circuit appears to be the headlight mounting bracket engagement with the crash sensor wiring along with damage to powered wiring. In the other involved vehicles, the mechanism which could create a sufficient negative electrical transient in a crash is not fully understood and is under investigation. Airbag non-deployment and/or lack of pretensioner operation can increase the risk or severity of injury in a crash.
Recall Schedule:
Notifications to distributors/dealers will be sent on January 21, 2020. Copies of dealer communications will be submitted as they are issued.
Notifications to owners of the affected vehicles will occur by March 17, 2020. A copy of the draft owner notification will be submitted as soon as it is available."
https://static.nhtsa.gov/odi/rcl/2020/RCLRPT-20V024-6050.PDF
"This ASIC does not have sufficient protection against negative electrical transients that can be generated in certain severe crashes, such as an underride frontal crash where there is a large engine compartment intrusion before a significant deceleration. In these cases, the crash sensor and other powered wiring can be damaged and shorted so as to create a negative electrical transient of sufficient strength and duration to damage the ASIC before the deployment signal is received in the SRS ECU. This can lead to incomplete or nondeployment of the airbags and/or pretensioners. In model year 2014-2019 Corollas, one potential mechanism contributing to the short circuit appears to be the headlight mounting bracket engagement with the crash sensor wiring along with damage to powered wiring. In the other involved vehicles, the mechanism which could create a sufficient negative electrical transient in a crash is not fully understood and is under investigation. Airbag non-deployment and/or lack of pretensioner operation can increase the risk or severity of injury in a crash.
Recall Schedule:
Notifications to distributors/dealers will be sent on January 21, 2020. Copies of dealer communications will be submitted as they are issued.
Notifications to owners of the affected vehicles will occur by March 17, 2020. A copy of the draft owner notification will be submitted as soon as it is available."
https://static.nhtsa.gov/odi/rcl/2020/RCLRPT-20V024-6050.PDF
