U0123 — Lost Communication with Yaw Rate Sensor (YRS) Module

What it means

Generic U0123 indicates peers (ABS/ESC, IPC, ECM, PSCM) stopped receiving the yaw rate sensor module messages. Typically on HS-CAN (~500 kbps) with ABS/ESC and steering systems; sometimes routed via a chassis gateway. OBD-Codes.com

Typical symptoms

  • ABS/ESC/Traction lamps; stability assist disabled
  • Possible EPAS/cruise limitations; U-code cluster with U0124/U0126. RepairPal.com

Why it sets

  • Message timeout from the YRS module; lost-comms monitor trips after calibrated timer.
  • Bus/physical faults on HS-CAN (opens/shorts/termination), or sensor module transceiver enters error-passive/bus-off. Use HS-CAN checks (~60 Ω key-off, bias ~2.5 V). NHTSA Static

Common root causes

Power/ground loss at YRS; HS-CAN wiring/termination problems; connector issues near center-tunnel/under seat; internal YRS failure; aftermarket device interference. OBD-Codes.com

Professional diagnostics

Global scan/topology → confirm YRS offline; verify feeds/grounds; HS-CAN resistance/voltage/scope; isolate branches (unplug YRS, sub-nets); connector pin-drag & water checks; only then software/part. NHTSA Static

Verified fixes

Restore power/grounds; repair CAN wiring; correct termination; clean/repin; remove add-ons; update or replace/initialize YRS; clear codes & drive-cycle.

Sources