U0123 — Data Bus: Yaw Rate Sensor Module – No Communication #

Note: The wording for DTC U0123 may vary depending on the vehicle manufacturer. Always refer to your OEM (Original Equipment Manufacturer) service information for precise terminology.

• U0123: Lost Communication With Yaw Rate Sensor Module (General OEMs)
• U0123: CAN Communication With Yaw Rate Sensor Module Fault (Ford, Mercedes-Benz)
• U0123: Yaw Rate Sensor Module No Signal (GM, Chrysler)
• U0123: Lost Communication With Lateral Acceleration Sensor (Toyota, Lexus)

Summary of DTC U0123 #

Diagnostic Trouble Code U0123 is flagged when a vehicle’s onboard computer detects a loss of communication with the yaw rate sensor module. The yaw rate sensor measures the vehicle’s rotational speed around its vertical axis—a key input for stability control and anti-skid systems. This code typically points to a fault in the data transfer network known as the Controller Area Network (CAN) bus, which connects multiple modules throughout the vehicle. When communication breaks down, critical safety systems may become disabled or operate in a limited mode. Prompt attention is vital to preserve your vehicle’s stability and handling characteristics.

Common Symptoms for Code U0123 #

When U0123 is stored, drivers may notice several warning indicators and experience changes in vehicle dynamics. Because the yaw rate sensor feeds data to stability and traction systems, its absence can reduce electronic safety features. Typical symptoms include:

• ABS (Anti-lock Braking System) warning light illuminated
• Stability control (ESC/ESP) or traction control warning lamp activated
• Intermittent or permanent disabling of stability/traction assist
• Possible reduction in braking performance or uneven braking
• Steering feels less responsive, especially during sharp turns or evasive maneuvers
• Fault codes present for other modules on scan tool

Probable Causes for Code U0123 #

U0123 is most frequently triggered by electrical connectivity issues but can also stem from failed sensors or control modules. The most common root causes, ranked by likelihood, are:

1. Faulty or disconnected yaw rate sensor module
2. Damaged, corroded, or loose wiring/connectors in the CAN bus circuit
3. Open or short circuit in CAN bus communication lines (CAN-H, CAN-L)
4. Faulty Electronic Control Unit (ECU) or powertrain control module (PCM)
5. Power supply or ground circuit problems for the yaw rate sensor
6. Software issues or module programming errors (rare)

Step-by-Step Diagnostic for U0123 #

A methodical approach is essential to pinpoint the exact cause of U0123. Here’s a reliable workflow for technicians and advanced DIYers:

1. Connect a professional scan tool and confirm U0123 is present. Check for related codes (especially U-codes for CAN communication).
2. Review freeze-frame data to identify when the code was set and under what conditions.
3. Visually inspect the yaw rate sensor module and its connectors. Look for signs of water intrusion, corrosion, or physical damage.
4. Check the integrity of wiring between the yaw rate sensor and its associated control unit. Pay special attention to the CAN-H and CAN-L circuits.
5. Verify power and ground at the yaw rate sensor using a multimeter. Ensure voltage is within OEM-specified ranges.
6. Perform a continuity test on CAN bus wiring if accessible. Look for open or short circuits.
7. Attempt to communicate directly with the yaw rate sensor via scan tool. If communication fails, the sensor or its circuit is compromised.
8. If all wiring checks out, consult OEM service information for module replacement or reprogramming procedures.

Possible Repairs for Code U0123 #

Repair actions should directly address the diagnosis findings. The following solutions are typically effective for resolving U0123:

• Reconnect or replace a faulty yaw rate sensor module
• Repair or replace damaged/corroded connectors and wiring in the CAN bus
• Restore power supply or ground to the sensor as required
• Replace blown fuses supplying the yaw rate sensor circuit
• Repair open or shorted CAN bus lines as identified by continuity testing
• If necessary, replace or reprogram a faulty ECU or PCM per OEM instructions

Is It Safe to Drive With Code U0123? #

Driving with U0123 is NOT recommended, especially in adverse conditions. While the vehicle may still operate, stability control and traction assist systems may be disabled or impaired. This can make the car more difficult to control during emergency maneuvers, wet or icy roads, or sharp turns. If this code appears, avoid high-speed driving and aggressive maneuvers until repairs are completed.

Vehicles Most Commonly Affected by U0123 #

This code is found across a wide range of modern vehicles, especially those equipped with advanced stability and traction control systems. The most frequently reported models include:

• Ford (Explorer, Fusion, F-150, Escape)
• Chevrolet (Malibu, Silverado, Equinox)
• Toyota (Camry, Corolla, RAV4, Prius)
• Mercedes-Benz (C-Class, E-Class, GLK, Sprinter)
• Dodge/Jeep (Ram, Grand Cherokee, Charger)
• Honda (Accord, CR-V, Civic)
• BMW (3 Series, 5 Series, X5)

Common Mistakes & Best Practices for U0123 #

Misdiagnosis is a frequent pitfall with communication codes. To avoid unnecessary part replacement or wasted labor, adhere to these best practices:

• Always check wiring and connectors before replacing the sensor module
• Do not ignore related CAN bus codes—address all communication faults
• Use only OEM or high-quality equivalent sensors and connectors
• Confirm repairs by clearing codes and performing a drive cycle
• Document all findings and test results for future reference

Quick FAQ for DTC U0123 #

Still have questions? Here are fast answers to the most common concerns about this code:

• Q: Can a weak battery cause U0123?
  A: Yes, low system voltage can disrupt communication between modules and trigger U-codes. Always check battery health before deeper diagnostics.
• Q: Will replacing the yaw rate sensor always fix U0123?
  A: No. While sensor failure is possible, wiring or CAN bus issues are just as common. Always verify the root cause before replacing parts.