For 1990-2009 cars

### Removal Procedure

Notice: The heated oxygen sensors each use a permanently attached pigtail and connector. Do not remove the pigtail from the heated oxygen sensor. Damage or removal of the pigtail or the connector affects proper operation of the heated oxygen sensor. Handle the oxygen sensor carefully. Do not drop the oxygen sensor. Keep the in-line connector and the louvered end free of grease, dirt, or other contaminants. Do not use cleaning solvents of any type. Do not repair the wiring, the connector, or the terminals. Replace the oxygen sensor if the pigtail wiring, the terminals, or the connector is damaged. Proper oxygen sensor operation requires an external air reference. This external air reference is obtained by way of the oxygen sensor signal and heater wires. Any attempt to repair the wires, the connectors, or the terminals results in the obstruction of the air reference and degrades the oxygen sensor performance. A dropped oxygen sensor is a bad oxygen sensor.

1. Disconnect the HO2S 1 electrical connector (2).
2. Remove the 2 HO2S 1 hold down nuts (3).
3. Remove the HO2S 1 (1) and gasket from the exhaust pipe.

### Installation Procedure

1. Install the HO2S 1 gasket onto the exhaust manifold.
2. Install the HO2S 1 (1) to the exhaust manifold.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

3. Install the 2 HO2S 1 hold down nuts (3).

Tighten
Tighten the HO2S 1 hold down nuts to 44 N·m (32 lb ft).

4. Connect the HO2S 1 electrical connector (2).