Code p0131 in 2002 saturn

P0131 BUICK - HO2S Circuit Low Voltage Bank 1 Sensor 1
https://www.autocodes.com/p0131_buick.html

Essentially the same as P0136 and P0137, a P0131 code refers to the first oxygen sensor on Bank 1. P0131 means the O2 oxygen sensor's voltage remained low for longer than 2 minutes. This, is interpreted by the ECM as a low voltage condition and sets the MIL. Bank 1 Sensor 1 is located in front of the catalytic converter.
Multidiag Access J2534 can help you reset it

This code does not mean to replace the sensor , testing is what is suppose to happen .
P0131 O2 Sensor Circuit Low Voltage Bank 1 Sensor 1

Honda Civic P0131 02 Sensor Diagnosis

I have the same problem on my 2006 mazda5. I go a new O2 sensor. Now I get p0131 and p2096 codes

http://www.obd-codes.com/p0131
basically a bad O2 sensor, click the link for more info

http://www.obd-codes.com/p0174
system running too lean, check and clean the MAF sensor, again click the link for more info

p0171-System Adaptive Fuel Too Lean

p0401-EGR

p0452-EVAP Fuel Tank Pressure Sensor Low Input

p0131-Upstream Heated 02 Sensor Circuit

Hope That Helps.

check your wiring make sure it is in the correct firing sequence! p0300 means misfire! p0131 means O2 sensor is not working properly.

P0131 - oxygen sensor circuit low voltage (bank 1 sensor 1)
http://www.obd-codes.com/p0131

P0137 - oxygen sensor circuit low voltage (bank 1 sensor 2)
http://www.obd-codes.com/p0137

www.obd-codes.com

These websites help me a lot. Hope they do the same for you too.