Hello im new to this forum page and need help, I have a 2012 g37x that got a p0500 (VSS) code a few months back.

I first lost data to my speedometer and didn’t really care since I planed on fixing it. I attempted to fix it but realized it’s a lot of work to remove the transfer case since it’s AWD.

I did a fluid change (about 5qts) from the trans pan and planned to get it fixed within a week or two after that. That same week my dash went blank, lost my ac and when I went to park the car otw to work the day it happened it wouldn’t come out of park unless I manually override.

I took it to a shop and got the sensor replaced but it didn’t fix anything. Now I’m looking into it being the harness for the VSS or worse a fried ECU/TCM.

Good thing is the car is mechanically sound still, I shifts through all 7 gears and idles fine. It’s just sluggish and has bad timing when shifting (either early or late, it can’t tell how fast the car wants to go). The dash has lost all function (Gear indicator, rpms, speed, temp, gas etc) as well as the AC.

If somebody can point me in the right direction I’d appreciate it a lot.

 

Dude, that sucks.
I'd start by tracing out and double checking all the grounds.
And start chasing wires from there

 

It sounds like the P0500 code is just part of a bigger electrical issue. Since your dash, AC, and shifter all stopped working, the problem is likely in the wiring or communication between modules.

First, check the wiring harness to the vehicle speed sensor. On AWD models, it runs near the transfer case and can get damaged or pinched. A shorted or broken wire here can affect other systems.

Next, inspect your ground connections. Bad or loose grounds can cause multiple electrical failures. Focus on the ones near the battery, engine block, and transmission.

You should also get a full system scan using a tool that can read more than just engine codes. Make sure it can access the TCM, dash cluster, and BCM. This will help rule out a bad ECU or TCM.

Lastly, check your fuses and relays, especially ones tied to the dash and AC. Even if they look good, test them for power and continuity.

The fact that it still drives and shifts is a good sign. Start with wiring and grounds, then move on to a full scan if needed.