I was searching only S14 before, because of the stricter smog reqs for the S14s, but when I widened my search to all 240sxs I found this:
http://www.240sxforums.com/forums/gener ... ensor.html
This post indicates that the function of the sensor/switch is to raise the idle rpm to offset the drop in rpm caused by the load of the power steering pump when turning at low speed.
If this is the only function I would think that the ECU won't throw the CEL, when the sensor is disconnected.
I just found this, too:
http://tech.240sxone.com/101/how-to-dia ... -on-240sx/
Assuming the list of error codes it contains is complete, the power steering sensor won't cause an error code.
I think I'm just going to hook up the new line and hope for the best. The worst case scenario is I have to buy a new hose at $70.