33920-57B30

The 56B30 is for an early 16V Vitara, the processor appears to be an Hitachi 63B01 variant. The package is 42-pins but pins 1 and 42 are not used, once these are discounted the pinout is identical. I have built a board to attempt to pull the code using Special test Mode but so far have been unsuccessful, the processor refuses to jump to the interrupt vector in external EPROM. It may not be possible to read the memory but i haven't given up yet.

This is a Denso manufactured ECU, Densos are often referred to by the large numbers printed on the label, that would make this an O3 ECU (letter O not zero).