Fisher & Paykel GWL11 rinse cycle problem

My Fisher & Paykel GWL11 washer cold water inlet valve works fine for the fill cycle and I can turn it on and off fine in diagnostic mode. After it goes to the rinse mode it barely trickles any water. There are no obstructions in the water supply line, and there are no error codes. I tapped on the back of the valve and it worked for the rest of the cycle. Was able to do this one more time, but no go now. Just wondering how to trouble shoot if it is the valve or if perhaps the control board not supplying the correct voltage to actuate the valve since it works fine other than the rinse mode? It is the original inlet valve. I replaced the hot water valve earlier this year due to it sticking open - near flood disaster there. Overall it has been easy to work on so far, one valve and two pumps in 10 years. Wifey doesn’t like the machine much so I figure it will probably hang in there for several more years!