Software Error Could Cause Loss Of Drive Power In Lucid Air

Certain 2022-2023 Lucid Air vehicles could experience a hardware communication fault that can cause a loss of drive power while the vehicle is in motion. This issue, identified in vehicles manufactured prior to December 2022, stems from a problem with the High Voltage Interlock (HVIL) safety mechanism.

Understanding the High Voltage Interlock (HVIL) System

The Lucid Air employs an HVIL system designed to protect against high voltage (HV) exposure during vehicle assembly, inspection, maintenance, or repair. The HVIL system ensures safety by opening contactors to remove HV from the HV bus if any connection point is deemed incomplete. Typically, these activities are performed while the vehicle is stationary, either in park or neutral. However, the HVIL design could also potentially open contactors while the vehicle is in drive or reverse, leading to a critical safety concern.

The Problem and Its Impact

Vehicles manufactured before December 2022 were found to be susceptible to intermittent hardware connection faults. These faults could trigger the HVIL system to open contactors while the vehicle was in motion, resulting in an unexpected loss of drive power. Lucid Motors documented ten instances of such incidents occurring in customer vehicles produced through November 2022.

This problem affected 5,251 model year 2022 and 2023 Lucid Air vehicles in the U.S. The incidence rate of these power loss events was calculated to be 0.2%, with ten reported cases among the affected vehicles. Despite this seemingly low percentage, the potential risk posed by an unexpected loss of drive power is significant and deemed an unreasonable safety risk.

The Solution: Remedy Software Update

In response to this issue, Lucid Motors initiated changes to manufacturing procedures, harness design and routing, inspections, and testing. These measures led to quality improvements, reflected in zero loss of drive power incidents due to HVIL-related intermittent connections after November 2022.

To address the issue in vehicles manufactured before these improvements, Lucid Motors developed a Remedy Software update. This update, rolled out to all affected customers via over-the-air (OTA) update starting on June 24, 2024, modifies the HVIL logic to prevent the removal of HV from the HV bus while the vehicle is in drive or reverse gear. Instead, the system will now display a Drive System Warning with instructions to contact customer care while in these gears. A Drive System Fault will only occur once the vehicle is placed in park or neutral.

Lucid Motors will notify owners of the affected vehicles about this safety risk and the availability of the Remedy Software. Owner notification letters are expected to be mailed on August 15, 2024. The company has designated this recall as SR-24-03-0, and the corresponding NHTSA campaign number is 24V-497.