FAQ: SMC ECU / WIRING LOOM COMPATIBILITY
SMC ECUs have been supplied with two external connection variations.The looms supplied with late revision ECUs are compatible with ALL SMC ECUs.The looms supplied with early revision ECUs are only compatible with early SMC ECUs.
Use of a late revision SMC ECU with an early loom will prevent reliable ECU to PC data link operation, however damage will not occur to either the ECU or PC.
Early looms can be converted to late revision specification by moving the Serial data link ground connection (black wire) contact terminal from Pin 21 position to Pin 34 position. If a switch I/P connection is required (available on late SMC ECUs only), insert a wire with attached contact terminal and seal into the vacant Pin 21 position. Refer to SMC standard loom.