Hi everone. I have a 1997 toyota camry with 123000 and it has been so good to me. However recently the check engine light came on. So i scanned it and got P0171 code, SYSTEM TOO LEAN. I dont know what i should do. I feel like replacing the o2 sensor but which one? Any ideas?Thanks guys!!!

 

V6 or 4 cylinder engine? Car built to California or Federal emissions. Look under hood for a sticker stating which one.

List of possible problems include:

-Engine exhaust gas and air intake leaks.

-Low fuel pressure or plugged injector(s).

-O2 or A/F sensor (depends on what emissions spec car was built to-Calif or Federal), Location Bank 1, Sensor 1 (for 4-cylinder) or Bank 1 or 2, Sensor 1 (for V6).

Typically on V6 engine Bank 1, Sensor 1 fails.

-MAP sensor.

-ECT sensor.

 

Hey thanks for the reply. Sorry about the missing information, its a 4 cylinder, it was bought brand new in nys and i cant find the sticker youre referring to so i assume its built to federal standards.

 

Typically if an O2 or A/F sensor problem a P0171 code will include a code for the problem sensor. Since there is no such code check the list of items posted first.

The Fed or Calif standard will affect which sensor the engine uses. A/F for Calif or 02 for Fed.

Have you checked on the underside of the hood for the sticker?

If a sensor issue typically it is the first sensor coming off the cylinder head.

If you know someone with an ODBII code reader the real time sensor data can be viewed to aid in diagnosis.