Description:

This diagnostic trouble code indicates that the DEF dosing unit signal is out of range high, which typically points to a short to 12 volts. This condition can cause the DEF dosing unit to malfunction or operate incorrectly, leading to potential issues with DEF injection and aftertreatment system performance.

Reaction:

The ECU may issue warnings or limit DEF system operation to prevent potential damage, which can impact overall vehicle performance and emissions control.

Recommendations:

• Inspect Wiring and Connections: Check for any damaged, frayed, or loose wiring and connectors that might cause a short to 12 volts. Repair or replace as necessary.
• Test DEF Dosing Unit Components: Use diagnostic tools to test the DEF dosing unit and associated components for proper operation.
• Check for Contaminants: Ensure that there are no contaminants in the DEF system that could cause electrical shorts.
• Replace Faulty Components: If a specific component, such as a sensor or control module, is found to be faulty, replace it.
• Reset ECU and Verify Operation: After addressing the issue, reset the ECU to clear the fault code and verify that the DEF dosing unit operates correctly.

Note:

Maintaining proper electrical integrity in the DEF dosing system is crucial for its correct operation. Regular inspections and timely repairs can prevent signal-related issues.