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Juan Crespo
Juan Crespo, Tech Trainer
Category: Subaru
Satisfied Customers: 1526
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
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A recently bought subaru 2003 outback, the dealer said they

Resolved Question:

a recently bought subaru 2003 outback, the dealer said they had replaced the oxygen sensor, however the engine light is on code is p0170
I'm very worried
Submitted: 10 months ago.
Category: Subaru
Expert:  Eric replied 10 months ago.


Which engine is in yours - the 2.5 or 3.0L

Customer: replied 10 months ago.
its an xs, I think its a 2.5 but not sure
Expert:  Juan Crespo replied 10 months ago.

Hi there. Different expert here.

Data Trouble Codes (DTC) don't necessarily indicate a component is bad. In this particular case, the onboard computer has set P0170 because it is having difficulties setting fuel trim. Most of the times, replacing the Oxygen sensors doesn't cure this issue; instead, the fix is achieved by cleaning the mass air flow sensor (MAF) - just be sure to use the appropriate cleaner (click here for example).

Also, you might want to check that the air filter housing and hose to the throttle body are properly seated and not allowing unmetered air into the engine.