Well my check engine light came on the other day. Dropped my Autozone and they say it's a P0551 Power Steering Pressure Switch Failure.

I looked up how to check it and it's reading ok ... open circuit at idle till you turn the wheel then goes to continuity to ground and the PCM is putting out 5 volts to it.

What else could I check? Could that mean the pump is going out?

 

P/S pump go out usually due to lack of P/S fluid and/or too much air in the system. When you cut the wheel from lock to lock (all the way left to all the way to the right) do you hear a whinning noise while turning. What color is your P/S fluid? chances is it might just need to be fluished and the connector to your P/S switch (both plug and socket) just needs to be cleaned and reconnected.

 

No whinning, Fluid is reddish color, connector is clean (hit it with contact cleaner and pinched it a bit to make sure it was tight)

How much fluid would I need to drain and refill it? What would one flush the system with?

 

you most probably have a pressure sensor switch in the high pressure line from the pump to the rack. its either faulty or you have low power steering fluid in the pump or pump reservoir. check your fluid level with the car running and at operating temp. if good, suspect sensor switch is bad.
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Tips: Always check the exhaust systems

 

Drained, refilled with fresh fluid ... Reset the computer and it's all good ... no more codes (For now anyway)