U1924 – Module Communication Failure

The ODBII code U1924 indicates a “Module Communication Failure,” meaning there is a problem with communication between vehicle modules, often due to a fault in the wiring, connectors, or the modules themselves.

The severity of ODBII code U1924 is moderate.

Common Causes For: U1923 U1923: “Module Communication Failure”

• Faulty wiring or connectors
• Failed or malfunctioning control module
• Poor ground connections
• Corroded or damaged pins in connectors
• Communication network issues (e.g., CAN bus problems)
• Software or firmware issues in modules
• Intermittent electrical connections
• Low battery voltage or power supply issues

Common misdiagnosis for U1924 U1924: “Module Communication Failure”

• Faulty wiring or connectors
• Defective control module
• Software issues or updates needed
• Power supply problems
• Grounding issues
• Intermittent communication issues
• Other module failures (e.g., CAN bus issues)
• Sensor malfunctions

Common Troubleshooting Steps

The OBD-II code U1924 indicates a “Module Communication Failure,” which typically means that there is a problem with communication between the vehicle’s control modules. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Check for Other Codes: Use an OBD-II scanner to check for any other trouble codes that may be present. Sometimes, multiple codes can provide more context for the issue.
• Inspect Wiring and Connectors:
• Visually inspect the wiring and connectors associated with the affected module(s). Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the ground connections, as poor grounding can lead to communication issues.
• Check Power Supply: Ensure that the affected module is receiving the proper voltage. Use a multimeter to check the power and ground circuits.
• Test the Module: If possible, test the affected module to see if it is functioning correctly. This may involve using specialized diagnostic tools or swapping the module with a known good one.
• Check for Intermittent Issues: Sometimes, communication failures can be intermittent. Try to replicate the conditions under which the code was set, and monitor the vehicle’s performance.
• Inspect the CAN Bus: If the vehicle uses a Controller Area Network (CAN) bus for communication, check for issues on the bus:
• Look for short circuits or open circuits in the CAN wiring.
• Use an oscilloscope to check the CAN signals for proper voltage levels and waveforms.
• Update Software/Firmware: Check if there are any software or firmware updates available for the vehicle’s modules. Sometimes, communication issues can be resolved with an update.
• Clear Codes and Test Drive: After performing any repairs or adjustments, clear the trouble codes and take the vehicle for a test drive to see if the code returns.
• Consult Service Manual: Refer to the vehicle’s service manual for specific diagnostic procedures related to the U1924 code and the affected module(s).
• 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 the specific make and model of the vehicle. By following these steps, you can systematically diagnose and potentially resolve the U1924 code and the associated communication failure.