Question

What are permanent and temporary DTC?

Answer 1

Diagnostic Trouble Codes (DTCs) are codes that are stored by a vehicle's onboard computer to indicate that there is a problem with the vehicle. These codes can be categorized into two main types: permanent and temporary (or pending).

Permanent DTCs:

• Permanent DTCs are codes that indicate a fault that has been confirmed and is considered persistent.
• These codes are stored in the vehicle's computer until the issue is resolved and verified by the system.
• They typically won't be cleared just by disconnecting the battery or using an OBDII scanner. The fault must be repaired, and the vehicle's system must run through certain cycles to ensure the issue is truly fixed before the code is cleared.
• Permanent DTCs ensure that persistent problems are addressed and not overlooked.

Temporary (Pending) DTCs:

• Temporary DTCs, also known as pending DTCs, indicate that the onboard computer has detected a fault but needs more information to confirm it.
• These codes are stored when a problem is detected, but it hasn't occurred frequently enough for the system to mark it as a confirmed fault.
• If the problem doesn't reoccur within a specific number of drive cycles, the temporary DTC may be cleared automatically.
• If the problem persists and meets the criteria set by the onboard computer, the temporary DTC will become a permanent DTC.

In summary, permanent DTCs indicate confirmed and persistent issues that require attention, while temporary DTCs indicate potential issues that need further monitoring before being confirmed as faults.