Introduction to DTC Extended Data

What is DTC extended data

DTC extended data refers to additional information related to the diagnostic trouble code, which provides more detailed fault description, fault occurrence conditions, fault impact and other aspects of data:

Fault Description: Provides a detailed description of the fault, such as fault type, fault location, fault cause, etc. These descriptions can help technicians better understand the nature and characteristics of the fault.

Fault conditions: describes the conditions and environment in which the fault occurs. This includes diagnostic conditions, vehicle status, sensor data, etc. Understanding the conditions under which the fault occurs can help technicians simulate similar conditions during the diagnostic process to better reproduce and resolve the fault.

Fault Impact: This describes the impact of the fault on vehicle performance and functionality. This includes impacts on safety, drivability, emissions, etc. Understanding the impact of a fault can help technicians assess the urgency and priority of the fault and take appropriate repair actions.

Troubleshooting suggestions: Provides troubleshooting suggestions and repair steps for specific faults. These suggestions may include inspection items, repair procedures, replacement parts, etc. Technicians can perform fault diagnosis and repair operations based on these suggestions.

The specific content of this information is generally defined by the customer. DTC extended data is obtained and exchanged through the Universal Diagnostic Test and Programming Communication Protocol (UDS), as shown below:

source: ISO14229-1

The technician sends a specific request to the vehicle's ECU to obtain extended data related to the DTC, which allows the technician to more accurately diagnose and resolve the vehicle's fault.