U0123 Lost Communication with Yaw Rate Sensor Module
The U0123 code indicates that the primary control module (PCM, ECM, or chassis control module, depending on the manufacturer) has lost communication with the yaw rate sensor module. This sensor measures the vehicle's rotation around its vertical axis, which is critical for electronic stability control (ESC/ESP), traction control, and, in some vehicles, active suspension systems. Communication typically occurs over the CAN (Controller Area Network) bus, so the loss can be due to wiring faults, sensor module failure, or CAN bus termination issues. Without the yaw rate signal, active safety systems are compromised or disabled, though the vehicle may remain drivable with limitations.
1. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.
2. Most Common Causes
- Faulty or damaged yaw rate sensor module
- Open or short circuit in the CAN bus wiring to the yaw rate sensor
- Failed CAN bus termination (missing or incorrect 120-ohm resistors)
- Power or ground supply issue to the yaw rate sensor module
- Corrosion in connectors or harness pins
- Fault in the master control module (PCM/ECM) or CAN bus gateway
3. Symptoms You Will Notice
- Illuminated Check Engine Light or stability control warning light
- Stability control, traction control, or active suspension systems inoperative or reduced function
4. Step-by-Step Diagnosis
Scan for additional related codes (e.g., U0100-U0300) to isolate the issue
Inspect the yaw rate sensor connector and wiring for damage, corrosion, or loose pins
Check CAN bus voltage and resistance at the yaw rate sensor connector (should be ~60 ohms with termination)
Verify power and ground at the yaw rate sensor module
Test the yaw rate sensor module by substitution or using a scan tool to monitor live data
5. Frequently Asked Questions
Is it safe to drive?▼
The vehicle may be driven, but stability and traction control systems will be disabled, increasing the risk of loss of control in slippery conditions or emergency maneuvers. It is recommended to have the issue diagnosed and repaired promptly.
How much does it cost to fix?▼
Repair costs typically range from $150 to $600, depending on the root cause. A simple wiring repair may cost $150-$250, while replacing the yaw rate sensor module can cost $300-$600 including labor.