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OBDII Pending and Active Codes

- Last Edited: Aug 27, 2023
- Popularity: 60 Views


What is the difference between OBDII Pending and Active Codes?

In the context of On-Board Diagnostics II (OBD-II), which is a standardized system used in vehicles to monitor and report issues related to emissions and engine performance, there are two main types of diagnostic trouble codes (DTCs): Pending Codes and Active Codes.

Pending Codes:
Pending codes are temporary DTCs that indicate a potential issue detected by the vehicle's onboard diagnostic system. These codes are generated when the system detects a parameter that falls outside the expected range, but the condition has not yet been confirmed to be consistent over multiple drive cycles or operating conditions. Pending codes are essentially "potential" trouble codes that serve as a preliminary warning.
The presence of a pending code does not immediately trigger the "Check Engine" light on the dashboard, but it does indicate that there might be an emerging problem. If the condition that triggered the pending code is confirmed over subsequent drive cycles, it will be promoted to an active code, and the "Check Engine" light will illuminate.

Active Codes:
Active codes are confirmed DTCs that indicate a specific problem has been detected and is consistently occurring in the vehicle. When the onboard diagnostic system detects an issue that meets the criteria for a DTC and confirms the problem over multiple drive cycles or operating conditions, an active code is generated. This active code triggers the illumination of the "Check Engine" light on the dashboard, alerting the driver to the presence of a problem that requires attention.
Active codes provide specific information about the nature of the issue, allowing mechanics and technicians to diagnose and address the problem effectively.

In summary, pending codes are temporary warnings of potential issues that have not yet been confirmed, while active codes are confirmed and indicate that a specific problem is currently affecting the vehicle's performance. Both types of codes are important for diagnosing and addressing engine and emissions-related problems in vehicles.

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