The purpose of this thread is to share experience testing the Motronic system (electrical side, not fuel side) on a B230ET using the Haynes instructions for the B23ET which is 'believed to be similar'.
All according to my Haynes Volvo 740 and 760 (petrol) 1982-1989 Owners Workshop Manual dated 1993 ISBN 1 85010540 5. The spine of the book is numbered 1258.
Testing Procedure Electrical side (page 155)
See
www.autoelectric.ru/auto/volvo/740/1989/740-89.htm for the correct wiring diagram and location of all the components and connectors etc.
Item 4, No earth continuity on pin 16 or 17. There is however earth continuity on pin 6, but only when the ECU is plugged in to the harness.
Item 15 does not apply. No Air Conditioning Advance Relay on B230ET.
Items 16 and 17 do not apply as there is a separate 'Power Stage, Motronic' which is specifically for the Fuel injectors.
This is NOT to be confused with the separate 'Ignition amplifier' on the B230FT and mentioned liberally in the FAQ. On the B230ET this amplifier is integrated in to the ECU itself so don't go looking for it.
I have not tested the Fuel injector resistances but it appears straightforward from the web site information above.
There is additionally the ' Radio Interference Supression Relay'