Saab 9-7x AWD force 4x4 engage

QuirkyAero

Registered Member
Original poster
Jun 22, 2020
18
Seattle, WA
I tried to help a neighbor last winter pull a car out of a ditch. I was on a level packed snow, so almost as on ice. It was hit and miss as the 9-7x wants to start in 2WD, slip the rear wheels and detect the slippage, then slam the transfer case into 4x4, which also tends to slip the front wheels. In the end there was not enough traction after the slippage.

What would it take to force the transfer case motor to engage? Is there a way to command this via OBD? Some sort of test commnad, maybe? Otherwise, would there be any downside to wiring in a button that powers up the transfer case engage motor?
 

Mooseman

Master Blaster
Moderator
Dec 4, 2011
21,832
Ottawa, ON
What you described is its normal operation. I suppose you could wire it but it won't stay in 4x4 as there is no brake in its encoder motor unlike the real 4x4 encoder. And it would also throw an error for an uncommanded shift. It's not a 4x4 truck. One did convert it to a 4x4 transfer case.

Converting from AWD to 4x4 Transfer Case (9-7x, Bravada, Rainier)
 

TJBaker57

Guru
Aug 16, 2015
2,000
Colorado

Mooseman

Master Blaster
Moderator
Dec 4, 2011
21,832
Ottawa, ON
Maybe however, again, no brake so it won't stay engaged.
 
OP
Q

QuirkyAero

Registered Member
Original poster
Jun 22, 2020
18
Seattle, WA
Understood! No worse or better than the system operating normally and sensing slip. I just want the option to pre-engage when you know you are going to slip. I'm not looking for full time, just want to avoid the loss of traction that occurs in the scenario I described earlier.

Same thing happened on the slight incline into our side street when it was ice covered. I stopped to check the mail, hopped into the 9-7x, and could not go forward. I would give gas, the rear wheels would slip, the transfer case would engage, but the momentum of the system would now cause the front wheels to slip. I could go sideways with more-or-less all the wheels slipping. How embarrassing :smile: I had to go backwards to flat, and go forward with a running start. Our Toyota Sienna AWD never had such an issue.

Slip-Bang pretty much sums it up.

The AWD on the 9-7x does well in most situations, but really falls down, IMHO, in a standing start situation. If the transfer case lock could be engaged before one gives gas, the 9-7x should easily climb up the slight incline from a standing start. At least that's my theory :smile:

I'll cobble something together and maybe can test it this winter.
 

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