Code U0123 on the 2020 Ford Explorer indicates lost communication with the yaw rate sensor module. This sensor measures vehicle rotation around its vertical axis and is essential for the electronic stability control (AdvanceTrac) system to function properly.
Yaw Rate Sensor Function
The yaw rate sensor detects how fast the vehicle is rotating during turns. Combined with steering angle and wheel speed data, this allows the stability control system to detect oversteer (rear sliding out) or understeer (front pushing wide) conditions and intervene with targeted braking to help maintain control.
Stability Control Disabled
With U0123 present, the AdvanceTrac system cannot determine vehicle rotation and will be disabled. The AdvanceTrac warning light illuminates, and you may also see ABS and traction control warnings. The Explorer remains driveable but without electronic stability intervention during loss-of-control situations.
Diagnostic Investigation
The yaw rate sensor is typically combined with a lateral acceleration sensor in a module located near the vehicle's center of gravity - often under the center console or beneath the front floor carpet. Check the module connector for damage. Verify power, ground, and CAN communication reach the sensor module.
Repair Path
Connector and wiring issues are common due to the under-floor location. If the sensor module has failed, replacement requires calibration to the vehicle's reference system using Ford IDS or equivalent diagnostic equipment.