Subaru Forester 2014 2.5i PZEV ( California ) , with CVT
[ this is just for reference ONLY. showing what I have done to 2014 Forester. NOT intended for instruction on how to repair it or maintaining it. I believe it is missing many details and steps to be used as Instruction.]
(this web site may not be available all the time, so you might want to make copy of it ).
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2017 of October around 110k miles.
Subaru start to have rough idle problem.
and it show code P0172 , system mixture Too rich.
Rough Idle Video ( if NO audio, try to download the file and play )
so I checked into Oxygen sensors ( 2 sensors ).
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My Subaru has 2 Oxygen sensors.
one closer to engine, before catalytic converter is called Fuel Air mixture sensor.
this sensor was dirty like second one after catalytic converter.
but, this picture was taken after I cleanred it.
oil covering sensor came from mixture of accetone and Automatic Transmission fluid I used to make thread loose.
I painted thread with it, so it come off easily.
I cleaned it more after this picture is taken, you can see still some carbon sooth inside through side holes.
Fuel Air mixture sensor ( before catalytic converter ) .
measured heater resistance. it is within accetable range.
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second one after catalytic converter is called just Oxygen sensor.
it looks dirty with black carbon sooth covered.
22 mm HEX socket.
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checking heater element resistance on second sensor after catalytic converter.
this picture show after I clean the sensor. ( it show resistance , acceptable according to service manual ).
2 Black wire was line to heater.
Pictures of Oxygen and Fuel Mixture sensors
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