Got a couple codes need some direction
 

So I have a 1995 SE Automatic with 281k and the CEL is on. The codes I pulled are 47 and 54. My understanding is that 47 is for crankshaft position sensor and 54 is transmission signal to the ecu. I'm trying to figure out where to go now. I figured for the 47 code I'll start with the actual sensor itself but as for 54 I'm lost.

Code 0407 (P1335) is for the crankshaft sensor located on the crankshaft pulley by the oil filter.

Code 0504 (P0600) says that the car's computer, the ECU, is constantly receiving an incorrect voltage from the TCM(Transmission Control Module). It could be a bad TCM or maybe the wire harness is damaged.

So next question is where is the TCM located and what's the routing for the harness from the ECU to TCM?

The TCM is on the floorpan of the car approximately underneath the heater & a/c controls. There are 2 modules there, one on top of the other. The bottom one is the TCM, the upper one is the BCM (Body Control Module).

See page 284 - http://boredmder.com/FSMs/Nissan/Maxima/1995/EL.pdf

The wire harness for the TCM is not a separate wire harness that you could remove and replace. The wires are integrated into a bigger harness that serves all kinds of things under the dash.

See page 100 - http://boredmder.com/FSMs/Nissan/Maxima/1995/AT.pdf

There is a self diagnostic built into the transmission. It starts on the bottom of page 46 -
http://boredmder.com/FSMs/Nissan/Maxima/1995/AT.pdf