Hi Mike,
Only way I know: you have to open left side of printer, then manually turn stepper motor. You should be able to rotate whole system a full cycle. If stuck, lubricate joints and check there is nothing loose to prevent action (ink debris?). You may turn the stepper in both directions.
Hint: Once run in this error and just turning the stepper solved it. There are sensors to locate the cam after electrical failure. My guess, there may actually be positions, sensors won't notice and you get (false) error.
Best,
Ari