Subaru Solenoid C /Flashing Green power light.

[Colec533]

My Outback 2002 2.5 is showing a Solenoid C code. I did two Drain and fills of the ATF and code is still present. Usually the green light comes on flashing after around an hour of driving or sometimes 5 min after I start driving. When the light comes on I start noticing performance issues and when coming to a stop 1 out of two times I would say I hear a decent clunk when going into park.

The issue was resolved when putting the FWD fuse in and car runs much better no clunk when going into park. After around an hour of driving the power light will apear again and it will take it out of FWD and back to AWD where I seem to have problems it won't switch back to FWD until the car has been parked for a few hours or when I start it back up in the morning. Il have around another hour and a bit of driving in FWD and randomly will switch back to awd and Power light will start flashing none stop again. 

Could this be my used tires I purchased as one of the tires was put on backwards which I just noticed  and the tires are two different brands with different tread wear. 

Or would this be my solenoid looking for advice  before I Pay to have the solenoid done.

Edited August 7, 2018 by Colec533

[1 Lucky Texan]

tires must be identical; brand/model/size and near each other in wear.

(without getting into esoterics like measuring rolling radii, etc.)

[heartless]

the tires are most likely what caused the problem (or hastened it along) but the real problem is the duty c & the transfer clutch pack - the only way to really resolve it is to replace them.

buying mismatched, used tires for these cars is a really bad idea.. for future reference, AWD Subarus really need to have matching tires all around - same brand, same model, same treadwear, and within 1/4 in circumference on all 4.

[idosubaru]

Replace the Duty C solenoid.  Usually wise to replace the cluches while you're in there and file down the grooves. 

If the FWD fuse works you can install a simple switch to toggle between FWD and AWD from the cabin and drive it indefinitely like that.  It's a good option sometimes, particularly here in the rust belt where the car might be rusted/worthless and fall apart if you work on it anyway - so an imperfect - but free and long term fix is a good option.  

1.  tires need to match in diameter (regardless of brand, tread wear, etc) - the diameter is the physical quantity that matters.   if they're all the same size and close to the same tread depth you're fine. 

2. if you have the flashing code and light - i'm fairly certain that's an electro-mechanical failure of the solenoid or supporting circuit - not anything else like fluid or tires.  

although i still think you should change the fluid and install/verify proper tires before proceeding, but the reality is the fluid/tires usually isn't causing the duty C circuit electrical/mechanical failure. 

[CNY_Dave]

The system that sets the code for the solenoid can only look at essentially the resistance of the solenoid circuit- too low a voltage and there's a short, too high and there's an open.

Unless there's a wiring problem, a solenoid coil like that (as a sensor or actuator) fails as described, so the advice to change it is good advice.

[Colec533]

On 8/8/2018 at 10:49 PM, idosubaru said:

Replace the Duty C solenoid.  Usually wise to replace the cluches while you're in there and file down the grooves. 

If the FWD fuse works you can install a simple switch to toggle between FWD and AWD from the cabin and drive it indefinitely like that.  It's a good option sometimes, particularly here in the rust belt where the car might be rusted/worthless and fall apart if you work on it anyway - so an imperfect - but free and long term fix is a good option.  

1.  tires need to match in diameter (regardless of brand, tread wear, etc) - the diameter is the physical quantity that matters.   if they're all the same size and close to the same tread depth you're fine. 

2. if you have the flashing code and light - i'm fairly certain that's an electro-mechanical failure of the solenoid or supporting circuit - not anything else like fluid or tires.  

although i still think you should change the fluid and install/verify proper tires before proceeding, but the reality is the fluid/tires usually isn't causing the duty C circuit electrical/mechanical failure. 

The FWD fuse will only work for 30 min to an hour and then the green power light will apear and it will go out and switch back to AWD it runs great in Fwd. if the fwd fuse stayed on all the time that would be perfect for me 

[grimaceNMike]

6 hours ago, Colec533 said:

The FWD fuse will only work for 30 min to an hour and then the green power light will apear and it will go out and switch back to AWD it runs great in Fwd. if the fwd fuse stayed on all the time that would be perfect for me 

Maybe toggle it on and off again every 30 min with a cabin switch? I have had duty C issue for at least 7 years, car drives like a tank. I don't take it on the freeways anymore and I pray for rainy days every time I drive.