2014 CX-9 4WD Light flashing...Any ideas?

[Ryan80]

Hello from Indiana. Our 2014 CX9 awd touring isn't liking the snow this year. On snowy roads the 4WD light will begin to flash for about 20 seconds. You can make the vehicle do this by semi aggressively getting into the gas. After about 20 seconds, when the 4wd light goes off, occasionally you can feel a little shudder and see the traction control light flash for a second. Again this is on snowy roads.

I have a decent scanner, an Autel 808. It shows no faults. By monitoring live data, I can see that I am definitely able to generate some wheel slip on the front wheels, the rear wheel are always steady at vehicle speed. I can see the coupling solenoid duty cycle fluctuate. I'm not sure what normal is, but it will get up to about 80% before the 4wd light begins to flash. Once the light starts flashing the coupling solenoid duty cycle drops to zero. And then when 4wd light goes out it starts showing a duty cycle again.

I put the car up on my lift and got a good look at everything. Visually I see no problems or causes for concern. My gut tells me the transfer case/ptu isn't transferring any power to the rear diff or maybe the coupling itself has failed. There are no abnormal noises when driving. The vehicle has about 190k on it

Any ideas of where to look or advice would be very helpful.
TYIA!
Ryan

 

[rowlands57]

Over that 190K have you serviced the PTU? Just checking as that's a long time to go on that unit. I have also heard of a connector at the rear diff that can get corroded and cause issues. Not a mechanical issue but electrical at the rear diff. It was a while back when i read about that but if you try to Google it there should be something to check up on.

 

[puma]

yeah your transfer case is shot, either the inside is all chewed up or the splines of the differential in the transmission are gone. Do a search in this forum there is a lot of threads about this.

If it was the connetor on the rear diff, the 4wd light would always be on. The flashing light is to let you know that the car didn't feel the rear wheels getting any power when the ECU asked for it.

 

[Ryan80]

Over that 190K have you serviced the PTU? Just checking as that's a long time to go on that unit. I have also heard of a connector at the rear diff that can get corroded and cause issues. Not a mechanical issue but electrical at the rear diff. It was a while back when i read about that but if you try to Google it there should be something to check up on.

The connector on the diff is okay. To my knowledge the PTU hasn't ever been serviced

 

[Ryan80]

yeah your transfer case is shot, either the inside is all chewed up or the splines of the differential in the transmission are gone. Do a search in this forum there is a lot of threads about this.

If it was the connetor on the rear diff, the 4wd light would always be on. The flashing light is to let you know that the car didn't feel the rear wheels getting any power when the ECU asked for it.

That makes sense. I can spin the drive shaft by hand and see a collar around the front right cv shaft turn. Not that it necessarily means anything, I just don't know how it's layed out inside the PTU.