I have a 2010 G37X. When I start the car everything is fine. Once it gets warmed up the awd light comes on and stays on. I don't even have to move the car and it comes on as soon as it gets warm. Thoughts?
Once it comes on the awd won't kick in if/when needed.

 

First thing is pull any codes. Without that it could be a million different things.

 

No codes given when I searched. But when I searched specifically under the ABS system it had a low voltage battery warning. I actually got a printout of that. Didn't really think much of that though. I'll find it and post

 

Please post the code(s). If the ABS module is malfunctioning, then the AWD can remain "offline." The AWD system receives the vehicle speed and brake pedal signals directly from the ABS module.

 

Low voltage can cause all sorts of issues. The alternator could have a fault and stop charging once the vehicle is warm.

 

It won't let me upload the url for the report but the code was c1109 abnormal battery voltage

 

All of the wheel speed sensors are operating and all are reading the same speed as the vehicle is moving

 

13.7v when car is running and I haven't seen it drop but maybe 0.2v at most

 

A couple other things that I am noticing is my atf is 220° and engine coolant is at 218°. Not sure what normal operating temp is but that is above boiling point. Engine cooling fan seems to pretty much always be running once it first cycles on. It doesn't come on when car is cold though so it seems to be operating properly. Car is just never drops temp enough for fan to turn off

 

Another thing is if I start from a cold start with no AWD light illuminated and I drive and turn extremely gentle, like super slow acceleration and turning the light won't come on. Once I accelerate at a normal pace or any abrupt movements the light comes on. Any idea what component actually controls that light? I was thinking a bad sensor but only sensor I could think of that tells ecu to turn on that awd light was wheel speed sensors. Which are all seemingly working fine.

 

Your issue appears to be with the ABS controller (not the speed sensors themselves). Your AWD controller (module) has its own set of diagnostic codes that can trigger the light. The AWD system receives speed and brake signals from the ABS unit. If the ABS unit is not functioning fully, then AWD can't do its thing.

You either have a power or ground issue within the harness or connector(s). If you have a multimeter you can test for voltage and continuity at the ABS harness and go from there. The factory manual will detail which pins to probe.

 

Awesome! Somewhere to start at least. I'll check that after work today. Thanks for the input. I'll post what my results are

 

That controller is under the middle console correct?

 

The ABS Module​ is located under the hood. That is where you need to focus at this point.

For reference, the AWD Module​ is located on the passenger side /under dash /behind glove box near the ECU and BCM (on the Coupe's at least).

 

I haven't been able to test the harness yet, I've been dealing with a death in my family but I was able to watch some live stream of some sensors while I was driving. I took a screen shot of what I saw.

I was parked when I took this image. The wheel speed sensors were all reading the same speed while stopped or moving. But this one, which I don't think is a abs wheel speed sensor was 18mph off from all the rest. I don't know where this sensor is though. There is a "v" that was cut off of the image. So it read "vhcl"