Oxygen Sensor Location

The oxygen sensor location is no secret. This part is a critical part of your car's emissions system. An oxygen senor works by generating an electrical current based on the difference in oxygen between the outside atmosphere and the engine interior. The Powertrain Control Module monitors the oxygen sensor and changes the air/fuel mixture based on the sensor's information.

Oxygen Sensor Location Tips

The oxygen sensor is designed much like a spark plug: a metal cylinder that screws into a metal surface and has wiring trailing out of one end. Exact oxygen sensor locations differ for each make, model, year and engine configuration. Your car's service manual should be considered the last word on the oxygen sensor location for your vehicle. That being said, here are some tips regarding general oxygen sensor placement:

• How many? That depends. Cars built prior to 1996 typically only had one oxygen sensor. Cars built after 1996 have more than one-depending on the engine configuration and umber of catalytic converters, some performance engines might have as many as 8 or 10 oxygen sensors!
• Typical locations. Oxygen sensors are usually located in the exhaust manifold, before the catalytic converter. Some engines have an oxygen monitor for each bank of cylinders (say, for a V-6 or V-8 engine), while some high-end vehicles use a sensor for individual cylinders. In cars built after 1996, a second sensor is located behind the catalytic converter in the exhaust pipe. If your vehicle has more than one catalytic converter, each unit will have its own sensor.
• What to look for. An oxygen sensor looks like a spark plug, with a hexagonal mounting and a wiring harness attached to the end. Bosch oxygen sensors, for example, can be removed and replaced just like plugs, but may need a special socket to accommodate the wiring harness.
• When is an oxygen sensor not an oxygen sensor? Technically, the sensors behind the catalytic converters are called "catalyst monitors" and not oxygen sensors. The name reflects the slightly different service these sensors perform.