EG–470 ENGINE – 2JZ–GE ENGINE TROUBLESHOOTING Back Up Power Source Circuit CIRCUIT DESCRIPTION Battery positive voltage is supplied to terminal BATT of the ECM even when the ignition switch is off for use by the diagnostic trouble code memory and air–fuel ratio adaptive control value memory, etc. WIRING DIAGRAM Engine Control Module R/B No.2 1 2A 2 EFI No.1 B-Y 4 EA1 B-Y 33 E10 BAT T B Battery F16878