Looking for any help and direction . 2004 g35 At when I first got the car it was throwing a p0300 & p0306 code & was a hard start . Once I started changing the coils & spark plugs I saw that cylinder #4 & #6 plug wires were swapped so I fixed those getting rid of both p0300 & p0306 codes . Now I’m getting a U1000 code & a pending Cylinder 1 misfire . Cluster isn’t showing what gear I’m in & AT check light in staying on . I’ve checked all grounds but I have not checked injectors . Ipdm box has been replaced as well & no corrosion on ECU or ipdm box connectors . Battery connections are good as well . Any help or anybody had these issues before ? If it’s a short to ground could I run a ground wire from the battery to the ECU & tcm ? Any help wanted !

 

Is it an internal or external TCM. I would start by inspecting the harnesses on the transmission to see if it's something obvious.

 

I’m on the way now to check can you tell me what it would look like besides the ECU if on the passenger side kick panel ?

 

Checking that kick panel is quick but you can also look at the left side of the transmission and see if it's got 3 separate harnesses mounted to the side of the tranny with about a foot of wire going into the transmission, or a single large harness plug right where the wires go into the transmission.

3 separate is the external, single large harness is the internal.

I think you should drive the vehicle down somewhere that can OBD2 scan for transmission codes and see what it's throwing, that will save a lot time guessing about what the issue is.