Check engine light subaru forester 03

the o2 sensor is located in the exhaust stream-from the exhaust headers, they are usually not more than 18 to 24 inches from the exhaust as it exits the engine-follow the pipes, they are in front of the catalytic converter-if you have a 4 cylinder, you only have one in front of the cat-if you have a v6, you have two. the o2 sensors BEHIND the cat only monitor the efficiency of the cat itself and have no bearing on driveabillity-concern yourself with the front o2 sensors, they control how the vehicle runs-they get 'tired' as they get older, and should be replaced as you get closer to 100,000 miles. It will generally run better and get better gas mileage.

For 1999 Subaru Truck Forester AWD 2.5L MFI 4cyl the Oxygen Sensor is located under hood, center, rear engine area, mounted on catalytic converter.



Fig. Oxygen sensor location-Forester 1998-2002 2.5L SOHC engine (click over image for zoom).

Generally, Bank 1 is front and Bank 2 is rear.

Hope helps.

Simply replace the o2 sensor you have no other choice

P0130----- 02 sensor circuit on bank #1 sensor #1
P0171------System too lean bank#1
The oxygen sensor on bank #1 needs a new one. If you have a V6 engine, the 02 sensor is screwed into the exhaust pipe up near the exhaust manifold on the same side #1 spark plug is, that's bank #1
I don't have my manual at the moment, so I can't tell you exactly where it is.
The sensor down by the catalytic converter is sensor #2 you don't want that one.

I think these codes are indicating a fault with your catalytic converter. The 02 sensors are each not returning the correct values to the ECM, causing a "suspect the 02 sensors" fault code.

rear oxygen sensor heater circuit malfunctiion.
standard code definition for all the vehicules.
I'm not a Subaru specialist but you your vehicule could be equipped with two oxygen sensors. The front one located into/near the engine exhaust manifold and the rear one located near the catalytic converter.
The specific code you're getting is associated to the rear one.
First check the wiring and connection of your rear sensor for burned wire or corrosion/dirty in the connector. If the unit has never been replaced and your millage is around/over 100,000 mile, it's easy to think that your unit could be bad and must be replaced.
Easy to replace by yourself as long as you have the right wrench size fiiting the the bottom like nut seat.

Hope it will help
Sorry for my englis
Dan

02 sensor =oxygen sensor or low fluid levels such as oil antifreeze or just routine maintenance as well ,if you inspect the motor area and find nothing wrong its most likely emissions again a sensor however merely disconnecting the negative terminal on the battery for a few minutes and then reconnect should turn the light off however the fact still remains that maintenance checkup should be in order as this is only a temporary fix as it will come on again until checked out { Auto-zone or Midas } will do a diagnostic check if the check engine light is on usually for free and tell you exactly what is the reason for it being on ..i hope this helps ...

no not nornal,you need to get it plugged in to a diagnostic computer to see which sensor set it off it means you have something that needs to be looked at,low oil could be a coincidence

Check the oxygen sensor!!!Ask a garage to look for codes on diagnostics,good luck!