There’s a lot of confusion on the web about the operation of the Mitsubishi AYC (active yaw control) hydraulics, as fitted to EVO 4 5 6 7 8 9 10 (iV V Vi Vii Viii iX X). The main confusion is that of the solenoid valves. Many seem to think that there are two separate solenoids, one for left and one for right. There isn’t. The system is made in a way so that one twin solenoid valve actually controls the high pressure flow to both the left and right connections. This is done by a twin solenoid valve. From its rest position, it can move the valve internals in two opposite directions. This allows the system to never be able to pressurise both lines to the rear differential at the same time, thus avoiding damage.

The flow diagram includes optional flow for the active centre diff (ACD) as fitted to some Mistubishi EVO 7 8 9 10 (Vii Viii iX X) vehicles.

Problems include corrosion of the pump plate, this is well documented. Other problems include blockage of the high pressure side filter, debris in the relief valve (causing it not to seal), and wear of the pump bearing, usually when the system has run dry. These are all items that should be checked during an AYC pump rebuild.

The flow diagram is only to show flow. It’s not physically accurate in terms of solenoid operation or passage flow etc. Its there to help give an understanding of the operation of the hydraulic system, and possibly help with fault diagnosis.

*We accept no responsibility any damage caused by the use of this information. You are using it entirely at your own risk.*

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