Heated Oxygen Sensor (Ho2S) Removal/Installation

WARNING:

• A hot engine and exhaust system can cause severe burns. Turn off the engine and wait until they are cool before removing the exhaust system.

CAUTION:

• Do not allow flammable objects such as the taping for bundling the wiring harness to come into contact with the exhaust system such as the exhaust manifold and silencer which reach high temperatures. Otherwise, it could cause fire damage.

NOTE:

• If penetrant lubricating spray penetrates the airflow hole of the HO2S, it could cause interference with the HO2S function.
• When removing the HO2S, wrap a rag around the lower position so that penetrant lubricating spray does not get sprayed into the airflow hole.

Fig 1: Wrapping Rag Around Heated Oxygen Sensor Airflow Hole

Courtesy of MAZDA MOTORS CORP.

Fig 2: Heated Oxygen Sensor, Connector, Brace Bar, Plate, Clip A And B (2WD)

Courtesy of MAZDA MOTORS CORP.

1. Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
2. Lift up the vehicle.
3. Remove the following parts:
   1. Plate (See EXHAUST SYSTEM REMOVAL/INSTALLATION .)
   2. Floor under cover (See FLOOR UNDER COVER REMOVAL/INSTALLATION .)
   3. Brace bar (See EXHAUST SYSTEM REMOVAL/INSTALLATION .)
4. Disconnect the HO2S connector.
   Fig 3: HO2S, Connector, Bracket, Clips And Nut With Torque Specification

   Courtesy of MAZDA MOTORS CORP.
5. Remove the nut.
6. Remove the clip A from the bracket.
7. Remove the clip B from the body.
8. Remove the HO2S using the SST.
   Fig 4: HO2S Using SST

   Courtesy of MAZDA MOTORS CORP.
9. Install in the reverse order of removal.