U1124 – Lost Communication with Vehicle Dynamics Control Module.

The ODBII code U1124 indicates that there is a loss of communication between the vehicle’s control module and the Vehicle Dynamics Control Module, which may affect systems related to stability and traction control.

The severity of ODBII code U1124 is generally considered moderate to severe.

Common Causes For: U1123 SCP (J1850) Invalid or Missing Data for Odometer

• Faulty Vehicle Dynamics Control Module (VDCM)
• Damaged or corroded wiring or connectors
• Poor ground connection
• Faulty communication lines (CAN bus issues)
• Software or firmware issues in the VDCM
• Malfunctioning sensors related to vehicle dynamics
• Issues with the power supply to the VDCM
• Interference from aftermarket modifications or devices

Common misdiagnosis for U1124 Lost Communication with Vehicle Dynamics Control Module.

• Faulty ABS module
• Wiring issues or shorts
• Faulty wheel speed sensors
• Malfunctioning engine control module (ECM)
• Incorrectly calibrated or faulty steering angle sensor
• Battery or charging system problems
• Faulty or corroded connectors
• Software issues or outdated firmware in the control modules

Common Troubleshooting Steps

When dealing with the OBD-II code U1124, which indicates “Lost Communication with Vehicle Dynamics Control Module,” there are several common troubleshooting steps you can follow to diagnose and potentially resolve the issue. Here’s a structured approach:

• Check for Other Codes: Use an OBD-II scanner to check for any additional trouble codes. Sometimes, multiple codes can provide more context about the issue.
• Inspect the Wiring and Connectors: **Visual Inspection: Check the wiring harness and connectors related to the Vehicle Dynamics Control Module (VDCM) for any signs of damage, corrosion, or loose connections.
• **Connector Pins: Ensure that the pins in the connectors are not bent or corroded.
• Check Power and Ground: **Power Supply: Verify that the VDCM is receiving the correct voltage. Use a multimeter to check the power supply to the module.
• **Ground Connection: Ensure that the ground connection for the VDCM is secure and functioning properly.
• Inspect the Vehicle Dynamics Control Module: **Module Condition: If possible, check the condition of the VDCM itself. Look for any signs of physical damage or water intrusion.
• **Reprogramming: In some cases, the module may need to be reprogrammed or updated with the latest software.
• Check for Communication Issues: **CAN Bus Communication: The VDCM communicates over the CAN bus. Use a scan tool to check if other modules are communicating properly. If other modules are also showing communication issues, it may indicate a problem with the CAN bus.
• **Termination Resistors: Ensure that the CAN bus termination resistors are present and functioning correctly.
• Perform a Hard Reset: Disconnect the vehicle’s battery for a few minutes to reset the system. Reconnect and see if the code reappears.
• Test the VDCM: If you have access to a compatible scan tool, perform a functional test of the VDCM to see if it responds to commands.
• Consult Technical Service Bulletins (TSBs): Check for any TSBs related to the U1124 code or the VDCM for your specific vehicle make and model. Manufacturers may have specific fixes or updates.
• Seek Professional Help: If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or technician who has experience with your vehicle’s specific systems.
• Document Findings: Keep a record of any tests performed, codes retrieved, and repairs made. This documentation can be helpful for future reference or if you need to consult a professional. By following these steps, you should be able to narrow down the cause of the U1124 code and take appropriate action to resolve the issue.