Hi,
Tested my 997.1 Turbo 2007 today to see if the front wheels engages when rear slips. Took some standstill starts on a wet epoxyfloor and the front wheels doesnt spin, only rears. I have no faults when checked with Durametric... Would like to try to diagnose it myself, but cant find any wiring diagram for awd control unit and front clutch. I also cant find any details for how the control solenoid for front clutch works. I believe it is a pwm signal say 0% dutycycle, clutch is open, and 50% dutycycle, clutch deliever 50% torque and 100% dutycycle, max torque applied? Anyone willing to share some info, or can point me in a direction? I have a 4-ch scope, but have not any working car to compare signals out from control unit...
Thanks

 

Sweet, now it's a GT2.

Sorry can't help but subscribed, interested in resolution.

 

just a quick note this system is rear drive and front wheels only kick in when needed.that means you can leave a patch mark and front wheel only engage 30%... take the car out in the wet and test again..

 

that was the case for the 996 turbo, but not the 997 turbo. See here... http://rennkit.com/wp-content/upload...-Operation.pdf. OP, you have a problem.

 

That is why I am interested in more details so i can try to find what is wrong Anyone have something they are willing to share?

 

It is a complex system, tied back to the primary ECU. Did you check for any codes from the ECU with a Durametric or PIWIS? Did you inspect the wiring and connection at the clutch pack? Wiring diagrams are hard to come by. But you can log into the Porsche website for the workshop manual and if not mistaken, pay by the hour for the privilege to scan them.

 

might be able to help... found this:

 

Great find thanks I have problem reading even if I zoom, but better than anything Where did you find it?

I have no fault code when reading with Durametric...

 

PM me, can zoom in and send the dwg in segments.

 

PM sent

 

Would the e-brake be up one click by chance?

I watched a video, and it said if you pull the ebrake one click, it disengages the front wheels.

 

Yes I have read that, but it was not engaged. I also believe I should get a warning driving with e-brake on?
Thanks for the tip

 

Hello BSH,


I agree with you should expect a duty-cycle control.
However when I engage the clutch by means of the PIWIS, currents are measured. (5 levels up to approx. 5-6 Amps)


Hans

 

Thanks for great info Hans


So if the clutch solenoid draw about 5-6 Ampere, the solenoid resistance should be about 2 ohm.


So you can choose via PIWIS 5 different clutch engage levels?
Is it a dealer PIWIS you have access to, or a clone?


Thanks

 

Yes 5 levels.
Official Porsche PIWIS