To erase a car code, also known as clearing a Check Engine Light (CEL), you can use one of a few common methods that involve resetting the car's computer (ECM/PCM). These methods are often used after repairing the issue that triggered the code.
Methods to Clear Car Codes
Based on common practices and the provided reference, here are the ways you can erase trouble codes:
Method 1: Disconnecting the Battery
A simple and widely known method involves temporarily disconnecting the car's main battery.
- Process: Disconnect your 12V battery for 15 seconds.
- Effect: This action effectively cuts power to the Engine Control Module (ECM) or Powertrain Control Module (PCM), which stores the trouble codes. By interrupting the power supply, the computer's volatile memory, where codes are held, is cleared.
- Outcome: This will turn the check engine light off and clear the computer's memory.
Important Note: Disconnecting the battery can also reset other vehicle systems like the radio presets, clock, and sometimes require security codes for reactivation.
Method 2: Using an OBD-II Scanner
The most recommended and precise method is using a diagnostic scanner tool.
- Process: Buy a scanner from Amazon, EBay, or an auto parts store and use it to clear the trouble codes.
- How it Works: An OBD-II scanner connects to your vehicle's diagnostic port (typically located under the dashboard). It communicates directly with the ECM/PCM, allowing you to read current and pending codes and select an option to 'erase' or 'clear' the codes.
- Benefits: This method clears only the trouble codes without affecting other memory settings like radio presets. It's also essential for diagnosing the code before clearing it.
Method 3: Pulling the ECM Fuse
Similar to disconnecting the battery, removing a specific fuse can also reset the computer's memory.
- Process: Find the fuse that supplies backup/memory power to the ECM and pull it for 15 seconds.
- Location: Fuse box locations vary by vehicle but are often under the hood or inside the cabin (e.g., under the dash or in the glove compartment). Consult your car's owner's manual to identify the specific fuse for the ECM or PCM.
- Result: Removing this fuse interrupts the constant power supply needed to maintain the computer's memory, thereby clearing stored codes.
Comparison of Methods
| Method | Difficulty | Tools Required | Side Effects (Potential) | Recommended For |
|---|---|---|---|---|
| Disconnecting Battery | Easy | Wrench | Radio presets, clock reset | Quick, basic reset |
| Using OBD-II Scanner | Easy/Medium | OBD-II Scanner | Generally none | Diagnosis & targeted clearing |
| Pulling ECM Fuse | Medium | Fuse puller (often included) | Potential partial memory loss | Targeted reset without full battery disconnect |
Disclaimer: Clearing a code without fixing the underlying issue will likely result in the code reappearing. Always diagnose the cause of the code before clearing it.
