U1930: U1930: "Module Communication Failure

Definition

The OBD2 code U1930 indicates a "Module Communication Failure," meaning there is a problem with communication between vehicle control modules, often due to a fault in the wiring, connectors, or the modules themselves

Common causes

Faulty wiring or connectors
Failed or malfunctioning control module
Corrupted software or firmware in the module
Poor ground connections
Interference from aftermarket devices
Low battery voltage or weak battery
Communication network issues (e.g., CAN bus problems)
Damaged or corroded pins in connectors

Common misdiagnoses

Faulty wiring or connectors
Defective control module
Software issues or updates needed
Power supply problems
Grounding issues
Intermittent communication issues
Other communication protocol failures

Troubleshooting steps

1. Check for Other Codes

Start by scanning the vehicle for any other diagnostic trouble codes (DTCs). Other codes may provide additional context or indicate related issues
2. Inspect Wiring and Connectors
3. Check the wiring harnesses and connectors associated with the affected module for any signs of damage, corrosion, or loose connections
4. Pay special attention to the ground connections, as poor grounding can lead to communication issues
5. Verify Power Supply
6. Ensure that the affected module is receiving the proper voltage and ground. Use a multimeter to check the power and ground circuits
7. If the module is not receiving power, trace the circuit back to the fuse box and check for blown fuses or damaged wiring
8. Check for Module Faults
9. If the module itself is faulty, it may not communicate properly. If possible, test the module in another vehicle or replace it with a known good module to see if the issue persists
10. Inspect the CAN Bus
11. U1930 is often related to issues with the Controller Area Network (CAN) bus. Check for any short circuits, open circuits, or interference on the CAN bus lines
12. Use an oscilloscope or a CAN bus scanner to monitor the communication signals on the bus
13. Look for Software Issues
14. Ensure that the vehicle's software is up to date. Sometimes, a software update can resolve communication issues between modules
15. If applicable, perform a reset or reprogramming of the affected module
16. Check for Environmental Factors
17. Sometimes, environmental factors such as moisture or extreme temperatures can affect module communication. Inspect for water intrusion or other environmental damage
18. Perform a Network Test
19. If you have access to a professional scan tool, perform a network test to check the communication status of all modules on the bus. This can help identify which module is causing the communication failure
20. Consult Technical Service Bulletins (TSBs)
21. Check for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued guidance on common issues related to U1930
22. Clear Codes and Test Drive
23. After performing the necessary repairs, clear the codes and take the vehicle for a test drive to see if the code returns. If the issue persists after following these steps, it may be necessary to consult a professional technician or a dealership for further diagnosis

Definition

Common causes

Common misdiagnoses

Troubleshooting steps

1. Check for Other Codes

2. Inspect Wiring and Connectors

3. Check the wiring harnesses and connectors associated with the affected module for any signs of damage, corrosion, or loose connections

4. Pay special attention to the ground connections, as poor grounding can lead to communication issues

5. Verify Power Supply

6. Ensure that the affected module is receiving the proper voltage and ground. Use a multimeter to check the power and ground circuits

7. If the module is not receiving power, trace the circuit back to the fuse box and check for blown fuses or damaged wiring

8. Check for Module Faults

9. If the module itself is faulty, it may not communicate properly. If possible, test the module in another vehicle or replace it with a known good module to see if the issue persists

10. Inspect the CAN Bus

11. U1930 is often related to issues with the Controller Area Network (CAN) bus. Check for any short circuits, open circuits, or interference on the CAN bus lines

12. Use an oscilloscope or a CAN bus scanner to monitor the communication signals on the bus

13. Look for Software Issues

14. Ensure that the vehicle's software is up to date. Sometimes, a software update can resolve communication issues between modules

15. If applicable, perform a reset or reprogramming of the affected module

16. Check for Environmental Factors

17. Sometimes, environmental factors such as moisture or extreme temperatures can affect module communication. Inspect for water intrusion or other environmental damage

18. Perform a Network Test

19. If you have access to a professional scan tool, perform a network test to check the communication status of all modules on the bus. This can help identify which module is causing the communication failure

20. Consult Technical Service Bulletins (TSBs)

21. Check for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued guidance on common issues related to U1930

22. Clear Codes and Test Drive

23. After performing the necessary repairs, clear the codes and take the vehicle for a test drive to see if the code returns. If the issue persists after following these steps, it may be necessary to consult a professional technician or a dealership for further diagnosis