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Discussion Starter · #1 ·
Had this problem first in January 2016, has never gone away. The pattern has changed since the cold start recall software patch, instead of happening immediately the problem occurs ~5 minutes after the car is turned on when the temperature gauge starts to move.

In cold weather (has done this at -2 C, which is not particularly cold), the car starts normally and drives normally, ~5 minutes into driving all of the indicator lights come on- check engine and traction control/vehicle dynamics control and ABS lights are solid, AT Oil temp and parking brake flash. Speedometer stops working (dial and digital, and there is no ELM reader output speed). Tac remains functional. Steering stiffens. You cannot shift through reverse to get to park (automatic), but if you turn the car off you can bump through reverse to park. If you turn the car back on all the problems remain.

A few minutes later the car comes back to life- speedometer starts working and the steering returns to normal.

Any ideas?

Codes: P0700, U0122. Both wipe with a handful of engine restarts.
The car has burned through 3 batteries. Subaru added conduction enhancement glue to all the wires. Fuses are fine. The speed sensor has been replaced. Up to date on recalls as of Dec 2020.
 

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2012 STI, 2007 Impreza RS
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It sounds like the the serpentine belt could be causing this (slipping). Have you changed the belt? Or belt tensioner?

A lot of those symptoms sound like when the alternator goes, and voltage becomes low. I've had a belt start to slip at times, making no noise, and the belt was still turning but at a much slower rate then the engine. I t would happen when alternator load was high.
 

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Discussion Starter · #3 ·
It sounds like the the serpentine belt could be causing this (slipping). Have you changed the belt? Or belt tensioner?

A lot of those symptoms sound like when the alternator goes, and voltage becomes low. I've had a belt start to slip at times, making no noise, and the belt was still turning but at a much slower rate then the engine. I t would happen when alternator load was high.
The belt and belt tensioner have been checked previously and were fine. I'm not sure this completely fits with the presentation of the problem of a reliable, probably electrical problem 5 minutes after starting the car, which disappears 5 minutes later.
 

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The belt and belt tensioner have been checked previously and were fine. I'm not sure this completely fits with the presentation of the problem of a reliable, probably electrical problem 5 minutes after starting the car, which disappears 5 minutes later.
Almost all the issues you described happen when the alternator fails and battery voltage gets to low, due to alternator not charging the battery.

My experience with alternator failure: Driving along, all of a sudden radio quits, shortly after all dash lights come on, speedo starts to bounce then quits. Then car dies, not enough voltage to keep electronics running. (I've had this exact experience several times from alternator failure, never got a battery light previous to everything going haywire)

So maybe you have a faulty alternator, that internally faults in cold weather, sporadically
If the belt was slipping, you could have low battery voltage. As I mentioned, I had a car where belt would be slippping but still turning very slow, all lights would dim, then it would suddenly jump back to normal. Had a hard time nailing the issue, that it was the belt.
 

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Had this problem first in January 2016, has never gone away. The pattern has changed since the cold start recall software patch, instead of happening immediately the problem occurs ~5 minutes after the car is turned on when the temperature gauge starts to move.

In cold weather (has done this at -2 C, which is not particularly cold), the car starts normally and drives normally, ~5 minutes into driving all of the indicator lights come on- check engine and traction control/vehicle dynamics control and ABS lights are solid, AT Oil temp and parking brake flash. Speedometer stops working (dial and digital, and there is no ELM reader output speed). Tac remains functional. Steering stiffens. You cannot shift through reverse to get to park (automatic), but if you turn the car off you can bump through reverse to park. If you turn the car back on all the problems remain.

A few minutes later the car comes back to life- speedometer starts working and the steering returns to normal.

Any ideas?

Codes: P0700, U0122. Both wipe with a handful of engine restarts.
The car has burned through 3 batteries. Subaru added conduction enhancement glue to all the wires. Fuses are fine. The speed sensor has been replaced. Up to date on recalls as of Dec 2020.
Reading back about your steering stiffening makes me think for sure it is the belt slipping. No electrical problem can make the steering get stiff.
EDIT - Skip that last comment, I just looked it up and 2015 has electric power steering
 

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Outback 2011 3.6R Premium
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At a guess I would suggest you more than likely have a bad ground/earth wire.

Both of the codes supplied relate to loss of communication with onboard modules (po700 is transmission and uo122 is VDC).

I would be checking the main ground wire from the battery to the engine (near the starter) and the one going to the transmission.

If you have a multimeter you can check how many Ohms the cables are from end to end (you want it to be as close to zero as possible)

Seagrass
 
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