Hi everyone,

Car: 2008 G37 Coupe 5AT

I'm having a weird issue here and I'm trying to diagnose it. I drove my car to a doctors office fine, and when I was leaving after this issue arose. If it helps, I live in Ontario, Canada and we are in the middle of a colder than usual period in Winter.

When I got in my car, the car would say the key is not detected, but I would be able to start up the car still (no weird engine noises or shaking). However, the entire gauge cluster would not be responsive. My fuel, rpm, speed, and temperature needle was at the bottom, and it is also not telling me how much fuel I have remaining on the screen either (I remember having half a tank remaining). Additionally, my shifter was stuck in Park, and I couldn't get into Drive without disabling the shift lock. I then drove home, and my car felt VERY slow to start moving after stopping, however at higher speeds it felt normal.

When I got home, I got an OBD2 reading for the codes U1000 and P0463. I disconnected the negative terminal of my battery for 30 minutes and reconnected it. This solved the key fob recognition issue.

However, my car is still having a nonresponsive gauge cluster and the shift **** is still stuck in P. The car seems to drive fine now, but I feel unsafe doing so until these issues are fixed. I checked the fuses in front if the battery and they were fine. Tomorrow, I plan on checking some of the fuses hidden beside the battery under the covering panels.

If you have any suggestion or experience with this issue, it would be GREATLY appreciated.

 

When you have multiple code, you need to troubleshoot the code with the highest priority. For now, ignore the P0462 (fuel sending unit) code.
In your case the U1000 has the THE HIGHEST priority and it is saying you have a "CAN Bus" communication issue.

CAN Bus is the network used for all the modules to talk to each other.
This explains why your dash is dead.... It isn't getting the information from the unified meter & A/C amp or ECU.

What is interesting, is that your OBD scanner was able to talk to the ECU and it does use the CAN bus.
Has any electrical work EVER been done to the car?
Do you have anything aftermarket, like a radio?

Generally you need special tools to troubleshoot (oscilloscope) to verify the quality of the CAN bus signal.
If you don't have those, you might want to take it to the dealer.

 

Maybe you have a bad battery?

Charge it up w/a trickle charger and reset the codes and see if they pop up again.

How are you able to drive it if you're stuck in P?

 

This sounds similar to a bug I had a while back. Went to shut down and the engine continued to run, dash, HVAC turned off. Key light came on, center display stayed on. Faulty connector? Mine did this when it was ~-30C. Southern Ontario got a beating!!

 

As I mentioned in my reply to the other thread you started regarding this issue: Per the FSM: Code U1000 is triggered when "(the) ECM is not transmitting or receiving CAN communication signal...for 2 seconds or more." The possible, and more than likely, cause are open or shorted CAN communication line(s). I am willing to bet that you have a bad ground connection somewhere.

I would:
a) check all of all of the fuses at the IPDM/er (fuse block next to battery)- as you mentioned;
a.2) wouldn't hurt to check fuses under the dash as well;
b) check all of the ground connections under the hood. Check for corrosion/ loose terminals/etc.;
c) check all of the connections at the ECM and also the BCM to make sure there is no water infiltration/corrosion/loose connections.

As SonicVQ mentioned, disregard the P0463 for now. Just make sure you have fuel in the tank. You can deal with that once you get more urgent problem resolved.

You mention you could not move the shifter from Park. For sh*ts and giggles, check your brake pedal switch. There have been several instances of these cars exhibiting odd behaviors being traced to a faulty brake pedal switch. Not likely but, hell, anything is possible.

Good luck!

 

So what was it? I'm having the same problem.