what is an inactive engine code
Active versus Inactive codes: [a] Active codes are the codes which are currently keeping the Check or Stop Engine. light on. Active codes are flashed via the Stop Engine Light (SEL). [b] Inactive codes are all the codes previously logged in the ECM. These codes can be. cleared by using the DDR. Inactive codes are flashed via the Check Engine Light. (CEL). NOTE: The Diagnostic Request Switch reads codes on the CEL and SEL when an DDR is not. available. The following steps will enable you to obtain codes.