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Why Can't Innova Scanners Erase Codes?

By R&D
Published on January 2nd, 2024

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Innova OBD2 scanners can clear certain check engine codes, but not all of them (and for a good reason). This article explores why some codes may be unerasable using your Innova scan tool.

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Why Can’t I Erase My Code?

You finally bought an OBD2 scanner from Innova with hopes of clearing your DTC, only to realize it can’t? Don’t worry! This is a common misconception across all OBD2 scanners in general. For over three decades, Innova has assisted countless customers in a similar situation, and like those before you, we're here to assist you every step of the way.

Here, we’ll explain the possible reasons why you may have trouble erasing the codes that's causing your check engine light. Oftentimes, you need to fix the underlying issue first.

Not All Codes Are The Same

Not all DTCs are simple to erase; their severity can vary, affecting how they can be cleared using a scan tool. While some code readers on the market don't differentiate between code severity, Innova's scanners do. Innova scanners not only identify the specific code(s) triggering the check engine light but also categorize the DTCs accordingly, making it extremely convenient for the user.

Common codes (such as active, confirmed, current, and stored codes) can be erased at any time. And although it's typically advisable to address the underlying issue before clearing the codes, Innova scan tools can clear them without requiring immediate repairs.

However, some diagnostic trouble codes have higher severity levels, potentially making them permanent DTCs. In certain cases, a DTC might be pending, indicating that the severity of the potential code is still being assessed. History codes represent past issues that have been resolved. 

So if you’re unable to clear a code, it’s highly likely that it’s a permanent, pending, or history code. To make things easier, Innova scan tools are capable of distinguishing between all these types of DTCs. Here’s how you can erase these severe DTCs.

Permanent DTCs

According to BAR (Bureau of Automotive Repair), permanent diagnostic trouble codes (PDTCs) are not like regular DTCs; they cannot be reset by disconnecting a vehicle’s battery or by using an OBD2 scanner.

“The only way to clear a PDTC is to fix the underlying problem with the vehicle that originally caused the PDTC and its corresponding DTC to set, and then allow the vehicle sufficient drive time to re-run the monitor that identified the problem in the first place. When the monitor runs without identifying a problem, the PDTC will clear itself.”

In other words, you need to first fix the issue that caused your DTC. Even with an OBD2 scanner, your vehicle will not allow the DTC to be reset/erased.

Pending DTCs

Pending codes result from either intermittent faults or faults that require the PCM to observe them in two consecutive warm-up cycles to trigger the code. If the fault doesn't reoccur within 40 warm-up cycles, the code will be automatically removed from memory. However, if the fault repeats the specified number of times, it will mature into a full-blown diagnostic trouble code (DTC), prompting the PCM to activate the check engine light.

History DTCs

History codes serve as records of past faults that were once active but have since been resolved. Think of them as battles won in the ongoing war of vehicle maintenance.

Clearing history codes varies: some can be erased using a scan tool, while others require a double code clearing. Certain codes will only clear after a set number of ignition or drive cycles, subject to specific conditions. Codes are archived in history to facilitate the diagnosis of intermittent issues. Some history codes resist erasure because the diagnostic tests necessary to evaluate the system or component demand specific operational conditions.

To clear a history code, consult the service manual for the particular code. The manual will outline the specific conditions required for the code to be cleared. Follow those conditions while driving the vehicle to clear the codes.

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