How to Read Diagnostic Trouble Codes (DTCs) in Service Mode

  • 2026-01-22: Released new reference article.

Introduction

To improve the diagnostics workflow, Service Mode has been updated to display and manage DTCs, which are latched Service-specific faults that require Service intervention (such as repair or replacement) in order to clear the DTC and restore vehicle functionality.

Informational PurposesAn informational icon, calling your attention
Note
A DTC panel will come to Toolbox in a future update.

How do DTCs Differ from Alerts?

  • Alerts can indicate a wide range of vehicle events that may not always require service-related actions (e.g., charging station errors, connectivity issues external to the vehicle, etc.). DTCs specifically represent confirmed faults that require service-related actions.
  • DTCs latch and persist across power cycles.
  • DTCs must be manually cleared by the technician.
  • DTCs mature over time and collect historical data.

Advantages of DTCs

  • DTCs are an industry standard system that technicians from other carmakers should easily recognize.
  • DTCs filter out false positives and direct technicians to real issues that require repair/replacement.
  • DTCs provide historical context—like a “mini-Autodiag”—to streamline diagnosis.

Accessing and Managing DTCs

To view DTCs, enable Service Mode and on the vehicle touchscreen, touch Tools > Alerts & DTCs.

DTCs are displayed in the Diagnostic Trouble Codes - DTCs panel (Figure 1).

Figure 1.
The information and actions available in this panel (Figure 1) are described below:
  1. UI Button to clear all DTCs
  2. UI Button to clear all DTCs on a specific ECU
  3. Description of the DTC
  4. Additional DTC information, such as a description of the potential impact of the DTC, how the DTC was set, and the conditions required to fully remedy the DTC.