o2 sensor location?

2003 GMC SONOMA

18,900 MILES

LARRYW60

MEMBER
1 POST

Getting codes P0174 and P0155 on my 2003 GMC Sonoma 4.3 L, 2wd. Already replaced MAF, Dist (leak), fuel filter, Injectors (erroded and leak) and both upstream O2 sensors. Found gas cap loose 50+ miles after reading codes. Help?

Jun 30, 2012 at 12:05 PM

RASMATAZ

✓ASE Certified Mechanic
75,992 POSTS

Where is bank 2 sensor 1? This guide will help us replace them with the locations below.

https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor

Heated Oxygen Sensor (Bank 1 Sensor 1) (4.3L VIN W)In left exhaust pipe, in front of catalytic converter.
Heated Oxygen Sensor (Bank 1 Sensor 2) (2.2L VIN 5)In exhaust system, after catalytic converter.
Heated Oxygen Sensor (Bank 2 Sensor 1) (4.3L VIN W)In right exhaust pipe, in front of catalytic converter.
Heated Oxygen Sensor (Bank 1 Sensor 2) (4.3L VIN W)In exhaust system, after catalytic converter

Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.

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Jun 30, 2012 at 12:26 PM

KEN GOULD

MEMBER
1 POST

My question is where the malfunctioning o2 sensor is located. I was told bank #2 sensor #1 is defective, How do I know which one is defective there are four o2 sensors on this vehicle.

Jan 4, 2021 at 9:16 AM (Merged)

SATURNTECH9

✓ASE Certified Mechanic
30,869 POSTS

Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.

There you go.

Jan 4, 2021 at 9:16 AM (Merged)

Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.