Diagnostic Aids
When vehicle is in "Closed Loop", voltage on circuit No. 412 will vary between .1 and 1.0 volt. Ensure connection for circuit No. 413 is clean and tight. If an open is present in circuits No. 412 or 413, Code 13 will set. If Code 13 is intermittent, refer to TESTS W/O CODES article. Before replacing an ECM, ensure ECM connector is not damaged.