If my car uses a 2-wire oxygen sensor can I use a 4-wire oxygen sensor?

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.
Our vehicle may vary slightly from yours as models do change and evolve as they grow older. If something seems different, let us know and share your info to help other users. Do you have questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.
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.

code p 0136 refers to heated oxygen sensor (HO2S) 2 bank 1 ---circuit malfunction===causes ---heating inoperative ---wiring---HO2S--- ECM
also refers to oxygen sensor (O2S0 2 bank 1---circuit malfunction===causes --- wiring---O2S ---ecm
it also refers to heated oxygen sensor (HO2S) 2 bank 1 ---no signal===causes ---wiring --- HO2S---
code p 0137 refers to HO2S 2 bank 1 ---low voltage -===causes --exhaust leak---wiring short to ground ---HO2S--- ECM
it also refers to O2S 2 bank 1---low voltage ===causes exhaust leak---wiring short to ground ---O2S ---ECM
to set you up here-- there are 4 oxygen sensors in the system
2 are heated oxygen sensors (HO2S) on in each exhaust manifold or exhaust pipe before the cat converter and
2 oxygen sensors (O2S) -- one in each exhaust pipe after the cat converters
heated oxygen sensors have 4 wires and O2S sensors normally only 2 wires
it is more that possible that you changed the wrong sensors and in the process damaged the delicate wires with the incorrect spanner being used

depending on the engine make
v8 and v6 have 2 oxygen sensors( O2S) , one after each cat converter with 2 wires and 2 heated oxygen sensors ( HO2S) in the exhaust manifold/ pipe before the cat converter with 4 wires each
6 cyl and 4 cyl engines have one oxygen sensor after that cat converter and one heated oxygen sensor before the cat converter

Stands for Heated oxygen sensor. You will see it designated like this: HO2S. Later model cars use a heater circuit in the oxygen sensor to heat it up for quicker operation. This is why you see 4- wire oxygen sensors; a heating element in the sensor requires 2 more wires- a power wire to the element and a ground wire for it.

Locate the two oxygen sensors on either side of the Sonata's catalytic converter on the exhaust manifold. The Sonata's oxygen sensor is gold and shaped liked a spark plug.

2 Remove the Sonata's wiring harness from the end of the two oxygen sensors using your fingers. Do not damage the end of Sonata's wiring harness.

3 Remove the two oxygen sensors from the Sonata's manifold using the oxygen sensor wrench.

4 Apply the anti-seize compound to the threads of the Sonata's two new oxygen sensors.

5 Install the two new oxygen sensors to the Sonata's manifold using the oxygen sensor wrench. Re-attach the wiring harness to the two new oxygen sensors using your fingers.

Grand Cherokee oxygen sensor locations for 4.0 and 4.7 engines







Four wires (circuits) are used on each O2 sensor:

• 12–volt feed circuit for the sensor heating element
• Ground circuit for the heater element
• Low-noise sensor return circuit to the PCM
• Input circuit from the sensor back to the PCM to detect sensor operation

O2S Sensor removal Never apply any type of grease to the oxygen sensor electrical connector, or attempt any soldering of the sensor wiring harness.
WARNING: THE EXHAUST MANIFOLD, EXHAUST PIPES AND CATALYTIC CONVERTER(S) BECOME VERY HOT DURING ENGINE OPERATION. ALLOW ENGINE TO COOL BEFORE REMOVING OXYGEN SENSOR.
1. Raise and support vehicle.
2. Disconnect O2S pigtail harness from main wiring harness.
3. If equipped, disconnect sensor wire harness mounting clips from engine or body.
CAUTION: When disconnecting sensor electrical connector, do not pull directly on wire going into sensor.
4. Remove O2S sensor with an oxygen sensor removal and installation tool.

02S Sensor installation
Threads of new oxygen sensors are factory coated with anti-seize compound to aid in removal. DO NOT add any additional anti-seize compound to threads of a new oxygen sensor.
1. Install O2S sensor. Tighten to 22 ft. lbs. (30 N·m) torque.
2. Connect O2S sensor wire connector to main wiring harness.
3. If equipped, connect sensor wire harness mounting clips to engine or body. When Equipped: The O2S pigtail harness must be clipped and/or bolted back to their original positions on engine or body to prevent mechanical damage to wiring.


Hope thats help (remember comment and rated this).

At the shop we test the oxygen to determine which one is bad.
1. Disconnect the the negative of the battery cable.
2.Disconnect the wiring harness from the oxygen sensor.
3. Remove the oxygen sensor.
To install new oxygen sensor.
1. clean the thread on the mount.
2. install oxygen sensor.
3. connect wiring harness
4. connect battery cable.

You have an heated Oxygen sensor. 2 of the wires heat up the sensor and keep it at a certain temperature, it is turned on and off by the computer. The other 2 are use to send a very low voltage reading back to the computer to tell the computer if the engine is running rich or lean. I don't have a diagram to tell you which wire does what but you can get a manual and that should give you the information that you need and tell you how to trouble shoot it to tell if the sensor is bad or not, you may want to look for a wire laying on the exhaust, I have found wires burnt and lay on the metal.