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Location of O2 Oxygen Sensor

Are you trying to find the location of the Oxygen O2 sensors in your Mercedes Benz? Well, pictures are worth a thousand words, so here is one.

Take a look at the picture and it will show where the Oxygen O2 sensors are located. If you are trying to find any of these sensors: Bank 1 Sensor 1, Bank 1 Sensor 2, Bank 2 Sensor 1, Bank 2 Sensor 2 take a look at the picture below.

Click to view larger image.
Click to view larger image.

To clarify a few things.  This is (was) a 320 M112 engine. Keep in mind that this is the typical configuration for most Mercedes-Benz V6 and V8 engines such as the M113 M119 M272 M273.

Where to buy OEM Oxygen O2 Sensors and save?



If you have the check engine light on, especially for any of the codes below you will most likely need to replace the oxygen sensor. You can get the O2 sensor online at a fraction of the price. Universal sensors work too, but we recommend original equipment sensors. The original O2 sensors are typically made by Bosh. We have set up this Amazon search for original Mercedes Benz O2 Bosch sensors.

Where is Bank 1?

Bank 1 is on the side where cylinder 1 is located; that’s for any car. On the Mercedes – Benz V6 and V8 engines Bank 1 refers to the right side of the vehicle which is the passenger side, for left-hand drive vehicles.

  • Bank 1 Sensor 1 is the upstream (pre-cat) on the passenger side.
  • Bank 1 Sensor 2 is the downstream (post cat) on the passenger side.

Bank 2 is on the driver side. 

  • Bank 2 Sensor 1 is on the upstream (pre-cat) on the driver side.
  • Bank 2 Sensor 2 is the downstream (post cat) on the driver side.

Where is Sensor 1? 

Sensor 1 is the O2 sensor that is located before (upstream) of the catalytic converter or also called the pre-catalytic converter.

Where is Sensor 2?

Sensor 2 is the sensor that is located after (downstream) the catalytic converter or also called the post-cat.

Check engine light codes associated with a bad oxygen sensor. 

Bank 1 Sensor 1 (Upstream) (pre-cat)

  • P0130 O2 Sensor Circuit Malfunction (Bank 1 Sensor 1)
  • P0131 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1)
  • P0132 O2 Sensor Circuit High Voltage (Bank 1 Sensor 1)
  • P0133 O2 Sensor Circuit Slow Response (Bank 1 Sensor 1)
  • P0134 O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)
  • P0135 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)
  • P2080 Exhaust Gas Temperature Sensor Circuit Range/Performance (Bank 1 Sensor 1)
  • P2081 Exhaust Gas Temperature Sensor Circuit Intermittent (Bank 1 Sensor 1)

Bank 1 Sensor 2 (Downstream)  (post cat)

  • P2031 Exhaust Gas Temperature Sensor Circuit (Bank 1 Sensor 2)
  • P2032 Exhaust Gas Temperature Sensor Circuit Low (Bank 1 Sensor 2)
  • P2033 Exhaust Gas Temperature Sensor Circuit High (Bank 1 Sensor 2)
  • P0136 O2 Sensor Circuit Malfunction (Bank 1 Sensor 2)
  • P0137 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 2)
  • P0138 O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)
  • P0139 O2 Sensor Circuit Slow Response (Bank 1 Sensor 2)
  • P0140 O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 2)
  • P0141 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)

Bank 2 Sensor 1 (Upstream)

  • P0150 O2 Sensor Circuit Malfunction (Bank 2 Sensor 1)
  • P0151 O2 Sensor Circuit Low Voltage (Bank 2 Sensor 1)
  • P0152 O2 Sensor Circuit High Voltage (Bank 2 Sensor 1)
  • P0153 O2 Sensor Circuit Slow Response (Bank 2 Sensor 1)
  • P0154 O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 1)
  • P0155 O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)

Bank 2 Sensor 2 (Downstream)

  • P0156 O2 Sensor Circuit Malfunction (Bank 2 Sensor 2)
  • P0157 O2 Sensor Circuit Low Voltage (Bank 2 Sensor 2)
  • P0158 O2 Sensor Circuit High Voltage (Bank 2 Sensor 2)
  • P0159 O2 Sensor Circuit Slow Response (Bank 2 Sensor 2)
  • P0160 O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 2)
  • P0161 O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)

So that is it, how to find where the oxygen sensor is located in your car.

 How to replace a bad oxygen O2 sensor. 

Replacing the downstream / post cat O2 sensors is easy. It is easy just to get under the car to replace them. The upstream ones are a little more tricky, as there is not as much space available for you to work. Here are a few videos that can help you.

 

 

 

 

One comment

  1. Good site. Very informative.

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