Location of O2 Oxygen Sensor

 

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

Look at the picture; it will show where the O2 sensors are located. The diagram identifies Bank 1 Sensor 1, Bank 1 Sensor 2, Bank 2 Sensor 1, and Bank 2 Sensor 2.

This photo shows an M112 3.2-liter V6 engine. Remember that this is the typical configuration for most Mercedes-Benz V6 and V8 engines, such as the M113, M119, M272, and M273.

Where to Buy OEM Oxygen Sensors?

If you have the check engine light on, an oxygen sensor code does not prove the sensor has failed. Check the wiring, connector, exhaust leaks, heater circuit, live sensor data, fuel trims, and applicable software updates before replacing parts. You can get the O2 sensor online at a fraction of the price. Universal sensors work too, but use a direct-fit oxygen sensor matched to the VIN, engine, bank, and sensor position. Do not assume a universal splice-in sensor will match the heater and signal requirements, but we recommend original equipment sensors. Bosh typically makes the original O2 sensors. We have set up this Amazon search for original Mercedes-Benz O2 Bosch sensors.

Where is Bank 1?

Bank 1 is the cylinder bank that contains cylinder 1. That’s for any car. On the Mercedes – Benz V6 and V8 engines. On the engines shown here, Bank 1 is on the vehicle’s right side and Bank 2 is on the vehicle’s left side, viewed in the direction of travel. On a left-hand-drive vehicle, Bank 1 is on the passenger side.

• Bank 1 Sensor 1 is the upstream sensor before the catalytic converter on the vehicle’s right side.
• Bank 1 Sensor 2 is the downstream sensor after the catalytic converter on the vehicle’s right side.

Where Is Bank 2?

• Bank 2 Sensor 1 is the upstream sensor before the catalytic converter on the vehicle’s left side.
• Bank 2 Sensor 2 is the downstream sensor after the catalytic converter on the vehicle’s left side.

Where is Sensor 1? 

Sensor 1 is the upstream oxygen sensor located before the catalytic converter.

Where is Sensor 2?

Sensor 2 is the downstream oxygen sensor located after the catalytic converter.

What scanner can I use to troubleshoot the check engine light?

Before replacing an oxygen sensor, scan the engine control module and compare the fault code with live oxygen sensor and fuel trim data. The YOUCANIC UCAN-II Pro includes full AI Diagnosis, built in TPMS sensor programming, a rear VIN scanning camera, coverage for 140+ makes, 3,500+ active tests, and 1,000+ special functions. It has no subscription and no AutoAuth required

In addition to its diagnostic capabilities, the YOUCANIC scanner can help you reset maintenance reminders and service indicators, allowing you to stay on top of your vehicle’s regular maintenance schedule. This is important because regular maintenance is essential for keeping your Mercedes-Benz running smoothly and preventing significant problems down the line. Using the YOUCANIC scanner, you can ensure that your vehicle is always in top condition, reducing the risk of breakdowns and other issues that could cause inconvenience or costly repairs. Whether you’re a DIY mechanic or a professional technician, the YOUCANIC full system diagnostic scanner is essential for troubleshooting Mercedes-Benz problems and keeping your vehicle in top condition.

Oxygen Sensor Fault Codes.

Bank 1 Sensor 1, Upstream

• 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)

Bank 1 Sensor 2, Downstream

• 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)

Use the bank and sensor numbers to identify the correct oxygen sensor.

How to Replace an Oxygen Sensor.

Downstream sensors are often easier to reach than upstream sensors, but access varies by chassis and engine. Let the exhaust cool completely. Raise the vehicle only at approved lift points, support it with rated jack stands or a lift, chock the wheels, and never work underneath a vehicle supported only by a jack. Upstream sensors are often harder to reach because space is limited. Here are a few videos that can help you.