How to Replace Downstream Oxygen Sensor 2012-2021 Mazda 6
Difficulty: Moderate · About 60 min · Mazda 6
Replace the downstream oxygen sensor on the Mazda 6 shown, behind the catalytic converter. The underbody shields must be moved for access; confirm the replacement matches the downstream sensor and connector on your model year.
Tools you will need
- 10mm socket
- oxygen sensor socket
- trim clip tool
Parts and supplies
- Downstream oxygen sensor
Steps
Raise the vehicle and expose the sensor
Let the exhaust cool completely and support the vehicle securely. Remove the underbody aluminum shield clips and rear fasteners. Remove the additional skid shield if needed to reach the sensor connector.
Disconnect and remove the old sensor
Trace the downstream sensor lead to its connector and release the connector lock. Free the wiring from its retainers. Use an oxygen sensor socket to unscrew the sensor from the exhaust.
Install and reconnect
Thread the correct replacement into the same exhaust bung and tighten it securely without twisting the lead. Route the wiring through the original retainers, reconnect the plug, and reinstall the shields and clips.
Check operation
Lower the vehicle and start the engine. Check that the sensor wiring is clear of hot or moving parts and verify that the related warning or fault does not return.
Check your vehicle’s repair manual for exact specifications and fit.