Diagnostic Procedure with Cancel Code: 66

WARNING: This page is about a different car, the 2022 Subaru WRX. However, it is still accessible from the selected car via links, so may be relevant.

Cruise control calculation malfunction is detected.
Abnormal increase in target cruising vehicle speed is detected.
Abnormal condition is detected in which cruise control is not deactivated even after the brake pedal is depressed.

If the malfunction indicator light remains on or blinks, perform the diagnosis for engine. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE

If the malfunction indicator is not remaining on/blinking, this cancel code may be detected due to malfunction of the ECM. In this case, restart the engine and perform the cruise control setting operation again. If the cancel code is not detected, it is normal. (Temporary malfunction)