U1794 – OBD-II DTC

OBD-II DTC U1794 – SCP (J1850) Lack of Acknowledgment for Mirrors

DTC U1794 meaning

DTC U1794 refers to a communication issue within the vehicle’s network, specifically related to the mirrors. The code indicates a “Lack of Acknowledgment” for the mirrors when using the SCP (Serial Communication Protocol) over the J1850 communication bus. This means that the control module responsible for the mirrors is not responding to requests from other modules, leading to potential functionality issues.

DTC U1794 symptoms

Common symptoms associated with DTC U1794 may include:

• Inoperable side mirrors
• Mirror adjustment controls not functioning
• Warning lights on the dashboard related to mirror systems
• Other electronic features in the vehicle may also be affected

DTC U1794 causes

Several factors can lead to the triggering of DTC U1794, including:

• Faulty mirror control module
• Wiring issues, such as damaged or corroded connectors
• Software glitches in the vehicle’s control modules
• Issues with the J1850 communication bus
• Low battery voltage or electrical system problems

DTC U1794 seriousness

DTC U1794 is considered a moderate issue. While it may not prevent the vehicle from operating, it can lead to safety concerns if the mirrors are not functioning properly. Additionally, it may indicate underlying electrical or communication problems that could affect other systems in the vehicle.

How to diagnose DTC U1794

To diagnose DTC U1794, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the U1794 code.
2. Inspect the wiring and connectors related to the mirror control module for damage or corrosion.
3. Check the mirror control module for proper operation and any additional DTCs.
4. Test the J1850 communication bus for continuity and proper voltage levels.
5. Verify the battery voltage and electrical system integrity.

How to fix DTC U1794 step-by-step instructions

To fix DTC U1794, follow these steps:

1. Repair or replace any damaged wiring or connectors found during diagnosis.
2. If the mirror control module is faulty, replace it with a new or refurbished unit.
3. Update the software of the control modules if necessary.
4. Ensure that the J1850 communication bus is functioning correctly by checking for shorts or open circuits.
5. Clear the DTC using an OBD-II scanner and test the system to ensure the issue is resolved.

How to erase DTC U1794

To erase DTC U1794, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Access the diagnostic menu and select the option to clear or erase DTCs.
3. Confirm the action and wait for the scanner to complete the process.
4. Disconnect the scanner and perform a test drive to ensure the code does not reappear.

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