How to replace oxygen sensor? - 1998 Lexus LS 400

Oxygen sensors monitor the exhaust stream, comparing the oxygen content in it to the oxygen content of ambient air. When oxygen content is low, sensor voltage is high. When oxygen content is high, sensor voltage is low. The voltage created by the sensor is sent to the DME (engine control module) to help maintain a proper fuel mixture. The mixture preparation is used to keep the catalytic converters running at peak efficiency. The oxygen sensors used in E60 models covered in this article has four wires. Two of which are for oxygen sensor heating and two for the signal. The heater is used to get the sensor online faster. Previously, exhaust heat was used. One wire supplied a ground to the sensor for the signal, and the other was for the sensor signal.
Oxygen sensors should be replaced every 100,000 miles. In a perfect world that would be it. Wait until a specified mileage and replace the sensor. However, these sensors fail prematurely, set oxygen sensor fault codes and reduce fuel economy. In this article, I will show you how to identify the location of all four oxygen sensors and how to replace them. You will need an oxygen sensor socket to remove the sensors and remember to always work with a cool exhaust. Oxygen sensors are fragile. Do not drop, as damage may occur. Also, keep the sensor tip clean when reinstalling.
Oxygen sensors are laid out in banks, which refer to cylinders and in sensor numbers referring to before or after the catalytic converter. Bank1 or B1 refers to cylinders 1-3. Bank 2 or B2 refers to cylinders 4-6. Sensor 1 or S1 refers to the sensor before the catalytic converter. Sensor 2 or S2 refers to the sensor after the catalytic converter.
Remember that your car may have been serviced before and parts replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have so be prepared with different size sockets and wrenches.
Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Never work on your vehicle if you feel the task is beyond your ability.
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Figure 1 Bank 1 Sensor 1 is indicated by a yellow arrow. Bank 2 Sensor 1 is pointed out with a green arrow. Large Image ' Extra-Large Image
Figure 2 Bank 1 Sensor 2 has a green arrow. Bank 2 Sensor 2 is shown with a yellow arrow. Large Image ' Extra-Large Image
Figure 3 Replacing sensors before catalytic converter: Oxygen sensors are located in the exhaust manifold. Remove the engine covers. See our tech article on engine covers removing. Locate the oxygen sensor electrical connectors at the right side of the engine above the exhaust manifold. Label or mark the wiring harness to aide during reinstallation. I suggest replacing one sensor at a time so you do not mix up connectors. Using an oxygen sensor socket, loosen the oxygen sensor connection to the exhaust manifold. Do not unscrew yet. Large Image ' Extra-Large Image
Figure 4 Replacing sensors before catalytic converter: Pull the wiring harness out of the mounts (green arrows) along the valve cover. Bank 1 sensor 1 shown, bank 2 sensor 1 is similar. Large Image ' Extra-Large Image
Figure 5 Replacing sensors before catalytic converter: Next, disconnect the electrical connector of the oxygen sensor you are replacing (yellow arrow). First, remove the electrical connector from the mounting bracket (green arrow) by pulling straight up. Once out, disconnect the electrical connector by pressing the release tab and pulling it apart. Note the wiring harness color and the factory sensors color code sensors to help when replacing. Locate the color of the sensor you loosened. Using an oxygen sensor socket, remove the oxygen sensor from the exhaust manifold. Lightly coat the new oxygen sensor thread with anti-seize compound. Install the new oxygen sensor and tighten to 50Nm (37 ft-lb). Then reroute the wiring harness and connect the electrical connector. Repeat if replacing both sensors. Then reassemble the engine covers and clear any engine fault codes using a BMW scan tool. Large Image ' Extra-Large Image
Figure 6 Replacing sensors after catalytic converter: Oxygen sensors are located in the exhaust, behind the catalytic converters. Working below the transmission, remove the transmission splash shield. See our tech article on lower splash shield replacing. Using an oxygen sensor socket, remove the oxygen sensor connection to the exhaust manifold. When reinstalling the sensor, do not allow the harness to remain twisted (green arrow). Be sure it is properly routed and tension free. Large Image ' Extra-Large Image
Figure 7 Replacing sensors after catalytic converter: Next, disconnect the electrical connector of the oxygen sensor you are replacing. First, remove the electrical connector from the mounting bracket (green arrow) by pulling it straight out toward the left side of the engine. Once out, disconnect the electrical connector by pressing the release and pulling it apart (inset). Note the wiring harness color, factory sensors color code sensors to help when replacing. Locate the color of the sensor you loosened. Using an oxygen sensor socket, remove the oxygen sensor from the exhaust manifold. Lightly coat the new oxygen sensor thread with anti-seize compound. Install the new oxygen sensor and tighten it to 50Nm (37 ft-lb). Large Image ' Extra-Large Image
Figure 8 Then reroute the wiring harness and connect the electrical connector. Repeat if replacing both sensors. Then reassemble the engine covers and clear any engine fault codes using a BMW scan tool.

The code means that there is a problem with the heater element circuit of the heated oxygen sensor. Water getting inside the heated oxygen sensor connector can caused the heated oxygen sensor fuse to blow, which is a very common problem for this type codes. Before replacing the sensor, check for the condition of the heated oxygen sensor fuse and connectors.

you need oxygen socket and 3/8 ratchet wrench.easy way to replace oxygen sensor is to start vechicle let run few minutes just enough to get exhaust system hot so it will make it easier remove oxygen sensor.just remove heat shields disconnect oxygen sensor electrical connector then replace oxygen sensor.use penetrating oil let it soak around oxygen sensor for 20 minutes that will help make it easier to remove sensor.

TO REPLACE OXYGEN YOU NEED A SLOTTED SOCKET AND A TUBE ANTI SEIZE COMPOUND. MOST OF THE TIME NEW OXYGEN SENSOR ALREADY HAS ANTI SEIZE COMPOUND USED ON THE THREADS.TO REPLACE OXYGEN SENSOR FIRST CRANK VECHICLE FOR A FEW MINUTES SO YOU CAN REMOVE OXYGEN SENSOR MORE EASILY. ONCE YOU GET THE EXHAUST LITTLE WARM.YOU DISCONNECT OXYGEN SENSOR CONNECTOR TAKE SLOTTED SOCKET REMOVE OXYGEN SENSOR APPLY ANTI SEIZE ON OXYGEN SENSOR THREADS THE SCREW IT IN PLACE..WEAR LONG SLEEVES COVERALLS, SAFETY GLASSES KEEP RUST PARTICLES GETTING INTO YOUR EYES. AND LEATHER GLOVES KEEP HANDS FROM CUTS AND EXHAUST BURNS. IF YOU REPLACING DOWN STREAM OXYGEN SENSOR YOU HAVE TO RAISE VECHICLE SUPPORT ON JACKSTANDS. FOR UP STREAM OXYGEN SENSOR YOU CAN REPLACE WITHOUT RAISING THE VECHICLE.REASON I SAY CRANK ENGINE TO WARM UP EXHAUST SYSTEM BECAUSE METAL EXPANDS WHEN HOT THAT MAKES REMOVING OXYGEN SENSOR EASIER. IF YOU DONT CRANK VECHICLE THE COLD CAUSES METAL TO SHRINK MAKING HARDER TO REMOVE OXYGEN SENSOR.POSSIBLY DAMAGING SENSOR THREADS WHILE TRYING TO LOOSEN SENSOR FROM EXHAUST MANIFOLD OR PIPE. YOU CAN BUY SLOTTED SOCKET AND ANTI SEIZE COMPOUND AT ANY AUTO PARTS STORES.

WELL WHICH OXYGEN YOU REPLACING THE UPSTREAM OXYGEN SENSOR MOUNTED IN EXHAUST MANIFOLD AND THE DOWN STREAM OXYGEN SENSOR LOCATED IN THE EXHAUST SYSTEM AFTER THE CATALYTIC CONVERTER .YOU NEED A OXYGEN SENSOR SOCKET TO REMOVE IT.TO REMOVE OXYGEN SENSOR CRANK VECHICLE TO GET OXYGEN SENSOR HOT BECAUSE HARD TO REMOVE WHEN COLD.BECAREFUL DONT GET BURN ON EXHAUST MANIFOLD WHEN REMOVING OXYGEN SENSOR.AND WHEN INSTALLING NEW OXYGEN SENSOR USE ANTI SEIZE COMPOUND ON SENSOR THREADS.BUT MOST OF THE TIME NEW SENSOR WILL HAVE ANTI SEIZE COMPOUND ON IT.

P0130 Oxygen Sensor Circuit Malfunction - Bank 1 Sensor 1.
P0131 Oxygen Sensor Circuit Low Voltage - Bank 1 Sensor 1.
P0132 Oxygen Sensor Circuit High Voltage - Bank 1 Sensor 1.
P0133 Oxygen Sensor Circuit Slow Response - Bank 1 Sensor 1.
P0134 Oxygen Sensor Circuit No Activity detected - Bank 1 Sensor 1.
P0135 Oxygen Sensor Heater Circuit Malfunction - Bank 1 Sensor 1

Remove the Oxygen Sensor
1. Step 1 Start the engine and let it idle for four minutes to raise the exhaust system temperature. This will make removal of the oxygen sensor much easier and prevent damage to threads on the exhaust pipe.
   
2. Step 2 Turn off the engine.
   
3. Step 3 Detach the ground battery cable using a wrench.
   
4. Step 4 Locate the oxygen sensor or sensors you need to replace. The sensors are threaded into the exhaust pipes before and after the catalytic converter. The oxygen sensor has a cylindrical body and the approximate size of a spark plug.
   
5. Step 5 Raise the front of your vehicle using a floor jack and support it on two jack stands. This will help you gain access to the sensor or sensors if necessary. If you need to work under the vehicle, wear safety goggles.
   
6. Step 6 Unplug the sensor electrical connector.
   
7. Step 7 Unscrew the oxygen sensor using a box-end wrench or a ratchet and oxygen sensor socket.
   
8. Step 8 Remove the sensor or sensors from the vehicle.
   
Install the New Oxygen Sensor
9. Step 1 Apply a light coat of electrically conductive anti-seize compound to the threads of the new oxygen sensor.
   
10. Step 2 Thread the oxygen sensor into the exhaust pipe by hand first.
    
11. Step 3 Finish tightening the sensor using the box-end wrench or ratchet and oxygen sensor socket.
    
12. Step 4 Plug the sensor electrical connector.
    
13. Step 5 Lower the vehicle.
    
14. Step 6 Attach the ground, battery cable using the wren
    

something keeps blowing the O2 sensor out...may be bad plug wires...the engine gettign too much gas...too little gas you would have to bring to a good mechanic not dealership

they just unscrew from the exhaust pipe.

Heated Oxygen Sensor (HO2S) SPECIAL SERVICE TOOL(S) REQUIRED Description Tool Number Oxygen Sensor Wrench T94P-9472-A
Removal and Installation

1. Disconnect battery ground cable (14301). Refer to Section 14-01 .
   

1. On 3.0L (4V) engine remove cowl extension and right side of leaf screen.
   

1. Disconnect engine control sensor wiring (12A581) from heated oxygen sensors (HO2S) (9F472). Do not remove harness connectors from the brackets.
   

1. Raise vehicle on hoist. Refer to Section 00-02 .
   

1. NOTE: If excessive force is needed to remove a heated oxygen sensor, lubricate the heated oxygen sensor with penetrating oil prior to removal.
   
   Remove heated oxygen sensors from exhaust manifolds (9430) using Oxygen Sensor Wrench T94P-9472-A.
   

1. To install, reverse Removal procedure. Apply a coating of anti-sieze compound to threads of heated oxygen sensor. Tighten heated oxygen sensors to 34-46 Nm (26-34 lb-ft).
   
   
   Heated Oxygen Sensors—3.0L (4V) Engine