Without SUBARU Select Monitor

WARNING: This page is about a different car, the 2003 Subaru Impreza. However, it is still accessible from the selected car via links, so may be relevant.

Current trouble codes shown on the display are cleared by turning the ignition switch OFF after conducting the on-board diagnostics operation. Previous trouble codes, however, cannot be cleared since they are stored in the TCM memory which is operating on the back-up power supply. These trouble codes can be cleared by removing the specified TCM connector for at least 2 minutes.

CLEAR MEMORY:

Non-turbo model

Remove TCM connector (B55)

Turbo model

Remove TCM connector (B56)

The TCM connector is located in the line to the memory back-up power supply of the TCM. Removal of this fuse clears the previous trouble codes stored in the TCM memory.
Be sure to remove the TCM connector for at least the specified length of time. Otherwise, trouble codes may not be cleared.