An OBD2 scanner is a valuable tool for diagnosing car problems, but can it clear trouble codes? The answer is more nuanced than a simple yes or no. Understanding the different types of Diagnostic Trouble Codes (DTCs) – permanent, pending, and history – is crucial.
A standard OBD2 scanner can typically clear pending and history DTCs. Pending codes represent intermittent issues or those that haven’t fully matured into a confirmed problem. History codes are records of past issues that have been resolved. Clearing these with a scanner often involves selecting the “clear codes” or “erase codes” function.
However, permanent DTCs are a different story. As defined by the Bureau of Automotive Repair (BAR), these codes cannot be erased by disconnecting the battery or using an OBD2 scanner. Permanent codes indicate a persistent problem that needs to be fixed. Simply clearing the code won’t solve the underlying issue. The only way to clear a permanent DTC is to repair the problem that triggered it and then allow the vehicle’s onboard diagnostic system to run its monitoring cycle. Once the system verifies the problem is gone, the permanent DTC will clear itself automatically.
Pending DTCs, often caused by intermittent faults, will clear themselves if the problem doesn’t reoccur within a specific number of drive cycles (typically 40 warm-up cycles). If the issue persists, the pending code will transition into a confirmed DTC, potentially triggering the check engine light. An OBD2 scanner can clear these pending codes, but it’s important to note that this only removes the code from the scanner’s memory, not the vehicle’s computer. If the underlying problem remains, the code will likely reappear.
History DTCs serve as a log of past issues. These codes can sometimes provide valuable clues when diagnosing intermittent problems. While an OBD2 scanner can often clear history codes, some may require specific driving conditions or procedures to be erased. Consulting your vehicle’s service manual for the specific code is recommended. The manual will outline the necessary conditions for clearing the code, such as a specific number of ignition cycles or driving under certain conditions.
In conclusion, an OBD2 scanner can clear certain types of trouble codes, specifically pending and often history codes. However, it cannot clear permanent DTCs. Addressing the root cause of the problem is essential for resolving any type of DTC and ensuring proper vehicle function. While clearing codes with a scanner can be helpful for resetting the system and checking if the issue has been resolved, it’s crucial to remember that it’s not a permanent fix for underlying mechanical or electrical problems.
