What are readiness codes and how are they cleared?
The OBD system monitors the status of various components of the vehicle including emission controls. Some components are monitored continuously and others periodically. Each component has a corresponding readiness code that indicates if the test for it has been performed. Readiness codes are set to either “ready” (test has been run), “not ready” (test has not been run), or “not applicable” (vehicle not equipped with component in question). Pertinent codes must be in “ready” status before an OBD inspection can be performed. Readiness codes are cleared after a vehicle is repaired, or the battery or PCM has been disconnected. When this occurs, the readiness status for each non-continuous diagnostic monitor must be reset. This means that the vehicle must be operated through a complete drive cycle to reset the codes.
