U1872 – Control Module Communication Failure

The ODBII code U1872 indicates a communication failure between control modules in a vehicle, suggesting that one or more modules are not able to exchange data properly.

The severity of ODBII code U1872 is moderate.

Common Causes For: U1871 U1871: Control Module Communication Failure

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

Common misdiagnosis for U1872 U1872: “Control Module Communication Failure”

• Faulty control module
• Wiring issues
• Poor ground connections
• Corrupted software or firmware
• Faulty sensors
• Communication network issues
• Battery or power supply problems
• Intermittent connection faults

Common Troubleshooting Steps

The OBD-II code U1872 indicates a “Control Module Communication Failure.” This code typically suggests that there is a problem with the communication between various control modules in the vehicle. Here are some common troubleshooting steps to diagnose and resolve the issue:

• Check for Other Codes: Use an OBD-II scanner to check for any additional trouble codes. Sometimes, other codes can provide context or lead to the root cause of the communication failure.
• Inspect Wiring and Connectors:
• Visually inspect the wiring and connectors associated with the control modules. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the CAN (Controller Area Network) bus wiring, as this is often where communication issues arise.
• Check Power and Ground:
• Ensure that the control modules have proper power and ground connections. Use a multimeter to verify voltage and ground continuity.
• Check fuses related to the control modules and replace any that are blown.
• Test Control Modules:
• If possible, test the affected control module(s) to ensure they are functioning correctly. This may involve using specialized diagnostic tools or software.
• If you suspect a specific module is faulty, consider swapping it with a known good module (if available) to see if the issue resolves.
• Inspect the CAN Bus:
• Use a scan tool that can monitor the CAN bus for communication. Check for any irregularities in the data being transmitted.
• Look for short circuits or open circuits in the CAN bus wiring.
• Check for Interference:
• Ensure that there are no aftermarket devices or modifications that could be interfering with the communication between modules.
• Update Software/Firmware:
• Check if there are any software or firmware updates available for the control modules. Sometimes, manufacturers release updates to fix communication issues.
• 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 reappears.
• Consult Service Manual:
• Refer to the vehicle’s service manual for specific diagnostic procedures related to the U1872 code. This may provide additional insights or steps tailored to your vehicle model.
• 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 make and model. By following these steps, you should be able to identify and resolve the underlying issue causing the U1872 code.