Subaru Battery Drain

Michael Owner/Technician Russell Lea, Australia Posted   Latest   Edited  
Tech Tip
Battery Drain 8 Amp Draw

Hi team from sunny dry Australia, and thanks Scott for Diagnostic Network. Had a interesting problem the other day which without the right tools on hand would have been hard to find. This Subaru was towed in with a 8 amp battery drain with all systems off. 

So with all of these I usually leave the car in the carpark for an hour (with a recharged battery). Then with our thermal imaging camera go over the car. Normally under the dash and around fuse boxes is where I find faults (and the places i look). In this case it was by accident I looked under the passenger seat and found a red hot motor

The passenger side electric seat switch was powering adjustment motor in one direction. We replaced the switch and problem fixed. I have to admit that I was shocked to find that Subaru has allowed power to the electric seats with vehicle essentially off and asleep. It would be nice if others know of systems that have power when key is out, gives us places to look. I know that there are lots of systems now that have access to the battery when the vehicle is off. I would like to make a list of different systems others have found to have access to power. I know of some Audi systems when you open drivers door the fuel pump primes on diesel.

Scott Manager
Claremont, California
Scott Default

Hi Mike, It‘s great to see you online now, welcome aboard and thanks for sharing. Hope you‘re doing well.

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Marlin Technician
Estacada, Oregon
Marlin Default

Do you know of any vehicle which does NOT keep the seat powered all the time?

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Michael Owner/Technician
Russell Lea, Australia
Michael Default

Hi Marlin we actuall have been checking and have a Mercedes in at moment with no power to seat unless ignition is on

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Marlin Technician
Estacada, Oregon
Marlin Default

That makes sense, considering that it probably is controlled by a complex module which consumes a significant amount of power even when in stand-by. This will almost surely become more common, but almost all remained powered in my experience. … post, regardless!

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