EG–576 ENGINE – 2JZ–GTE ENGINE TROUBLESHOOTING ECM Power Source Circuit CIRCUIT DESCRIPTION When the ignition switch is turned on, battery volt-age is applied to the terminal IGSW of the ECM, and the main relay control circuit in the ECM sends a signal to the terminal M–REL of the ECM, switch-ing on the main relay. This signal causes current to flow to the coil, closing the contacts of the main relay and supplying power to the terminal + B of the ECM. If the ignition switch is turned off, the ECM contin-ues to switch on the main relay for a maximum of 2 seconds for the initial setting of the IAC valve. Engine Control Module EFI No.1 Fuse EFI Main Relay +B M-REL IGSW AM2 Fuse Ignition Switch Main Relay Control Circuit Battery E1 P18745 WIRING DIAGRAM Engine Control Module W-R 2 3 B-O Ignition Switch 1J 1E IGN J/B No.1 B-O II1 B-O 1 IGSW E18 E1 B-R 31 +B E10 IB1 B-Y 2 2 3 5 B-R EA2 B+ W-R 2 2 1 GR EA1 GR 24 E10 M-REL EF1 Main Relay R/B No.2 2 2 AM2 EF1 No.1 2A B Battery W-B BR 69 E9 E1 P18746