WITH A SCAN TOOL
Control module reset procedures are a very important part of OBD II System diagnostics.
This step should be done at the end of any fault code repair and at the end of any driveability repair.
Clearing codes can be performed by any of the methods below:
WITHOUT A SCAN TOOL
If there are still codes present, either the codes were not properly cleared (Are the codes identical to those flashed out previously-), or the underlying problem is still there (Are only some of the codes the same as previously-).