Mazda Says Don't Worry About Permanent DTCs
Mazda notes that on all models with IDS version 104 and higher, permanent DTCs are displayed. The purpose of a permanent DTC is to prevent customers from clearing them by disconnecting the battery cable in order to pass a smog check.
All PCM and TCM DTCs that turn on the check engine light can remain as a permanent DTC. They will not turn on the check engine light and cause drivability concerns.
If you encounter a permanent DTC, Mazda says ignore it and diagnose the current stored or pending DTC.
IDS will not clear permanent DTCs. They will only clear after conditions are met with some driving cycles. If you have performed a repair and a permanent DTC remains, Mazda says it is OK to release the vehicle back to the customer.