How-To: Replace Downstream Oxygen Sensor
Overview:
Under certain conditions, the downstream oxygen sensor may short out and fail. If this happens, the vehicle will throw a check engine light and report codes P0138, P0140, and possibly P013E. A replacement of the oxygen sensor is required.
Tools Required:
- 1/2" drive wrench and extension
- 22mm or 7/8" Oxygen Sensor Socket (Available on Amazon.com)
- Torque wrench (Available on Amazon.com)
Part Required:
GM part number: 2134698 (Available on Amazon.com)
Procedure:
Do not attempt this without the required oxygen sensor socket tool. It looks like this:
The downstream oxygen sensor is located behind the engine on the exhaust pipe, facing up. Disconnect the oxygen sensor harness. There will be a tab. I recommend pressing the connector in, then pressing the tab down, then pulling it out.
Using the oxygen sensor socket, remove the oxygen sensor. This may require a bit of force.
Old vs New. The new one appears to have a blue shield over it. Replacement oxygen sensors should already have anti-sieze on the threads.
Torque the oxygen sensor to 31 ft-lbs or 42 nm, and plug the harness back in.
Overview:
Under certain conditions, the downstream oxygen sensor may short out and fail. If this happens, the vehicle will throw a check engine light and report codes P0138, P0140, and possibly P013E. A replacement of the oxygen sensor is required.
Tools Required:
- 1/2" drive wrench and extension
- 22mm or 7/8" Oxygen Sensor Socket (Available on Amazon.com)
- Torque wrench (Available on Amazon.com)
Part Required:
GM part number: 2134698 (Available on Amazon.com)
Procedure:
Do not attempt this without the required oxygen sensor socket tool. It looks like this:
The downstream oxygen sensor is located behind the engine on the exhaust pipe, facing up. Disconnect the oxygen sensor harness. There will be a tab. I recommend pressing the connector in, then pressing the tab down, then pulling it out.
Using the oxygen sensor socket, remove the oxygen sensor. This may require a bit of force.
Old vs New. The new one appears to have a blue shield over it. Replacement oxygen sensors should already have anti-sieze on the threads.
Torque the oxygen sensor to 31 ft-lbs or 42 nm, and plug the harness back in.