U0123: Lost Communication with Yaw Rate Sensor Module

What it means

A control module has stopped receiving expected messages from the yaw rate sensor module. Stability functions that rely on yaw data may be limited or unavailable.

At a glance

• Usually lights the warning light of the system that lost communication

How it works

The yaw rate sensor module reports how quickly the vehicle is rotating around its vertical axis, data used by stability control to compare the vehicle’s motion with the driver’s steering input. Other modules expect those messages over the network. U0123 sets when a module stops receiving the yaw-rate module’s messages, so stability control may be limited or disabled.

Common causes

Most likely first.

1. Yaw rate sensor module power or ground fault
2. Damaged network wiring or connector
3. Yaw rate sensor module failure
4. Low system voltage

Symptoms

• Stability control warning
• Stability control may be unavailable
• Other communication codes

How to diagnose it

1. Scan all modules and save freeze-frame data plus related stability, network, and low-voltage codes to see whether the yaw-rate module is the only one offline.
2. Check battery condition and charging-system operation, because low voltage can interrupt sensor-module communication.
3. Locate the yaw rate sensor module using vehicle service information and inspect its connector, power and ground wiring, and network harness for damage or corrosion.
4. Use a scan tool to check whether the yaw-rate module responds and whether live yaw-rate data is available with the vehicle stationary.
5. If power and ground are present but the module remains offline, test the network wiring and connector circuits against the manufacturer’s specification.

Common fixes

• Correct a weak battery or charging-system problem.
• Secure or clean the yaw-rate module connector if it is loose or corroded.
• Repair damaged network wiring or terminals to the yaw-rate module.
• Restore a faulty module power or ground circuit.
• Replace the yaw rate sensor module if its wiring and supplies are sound but it does not communicate.

Can I keep driving?

The vehicle may remain driveable, but stability control that depends on yaw data may not intervene correctly. Slow down, avoid slippery roads and abrupt steering, and have the fault checked before relying on stability assistance.