What are confirmed, pending, and permanent codes?
There are three types of generic/standard
- Pending Codes
A pending code will not turn on your check engine light and indicates that a system on your vehicle is behaving abnormally, but not so much as to mean there is an actual problem.
For example a temperature sensor might have a normal operating range of 90-110 degrees, but 80-120 degrees is considered acceptable. Once the sensor starts to read 85 degrees it is outside of the "normal" range but isn't a problem yet, so a pending code will appear.
- Confirmed Codes
A confirmed code indicates that a vehicle system is experiencing an issue requiring your attention. In the temperature sensor example above, once the reading drops below 80 or above 120 degrees the vehicle would then throw a confirmed code as well.
- Permanent Codes
Permanent codes are a special type introduced more recently which can not be cleared using a scan tool. If you have a permanent code the vehicle will clear it itself once the cause has been addressed and sufficient data has been gathered by driving under different conditions (idling, stop and go, highway)
Generally permanent codes cover emissions related equipment.