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We often get asked: "Where is Bank 1 Sensor 1?" To answer that question, we decided to show you a few pictures of Bank 1 Sensor 1 to help you identify it on your car. 

On a four-cylinder engine, it is straightforward to locate Bank 1 Sensor 1. Simply open the hood, and locate the catalytic converter on the exhaust manifold. Be careful not to touch it as it may be hot. Bank 1 Sensor 1 is located right before the catalytic converter. 

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Mitsubishi Bank 1 Sensor 1 O2 Location
Mitsubishi Bank 1 Sensor 1 O2 Location
Hyundai Elantra Bank 1 Sensor 1 Location
Hyundai Elantra Bank 1 Sensor 1 Location

Honda Civic Bank 1 Sensor 1 O2 Location

On a six, eight, ten, or twelve-cylinder engine, it gets tricky to determine which one is Bank 1 sensor 1 because those cars typically have two upstream sensors. Many car manufacturers assign the passenger side of the engine as Bank 1 and the driver side as Bank 2, which is often the case in most European vehicles.

Mercedes-Benz Bank 1 Sensor 1 Location
Mercedes-Benz Bank 1 Sensor 1 Location


The truth is that Bank 1 sensor 1 can be on either side of the engine. The best way to determine which side is Bank 1 or Bank 2 is to look it up in your owner's manual. Look under the spark plug firing order section. Bank 1 refers to the side of the engine where the #1 cylinder is located.

Where is Bank 1 Sensor 1 Located? 

Regardless of the make and model, bank 1 sensor 1 is located between the engine and catalytic converter. This will be the only upstream sensor on in-line engines. On V-shaped engines, it is necessary to determine which is bank 1. 

What does Bank 1 Sensor 1 Mean? 

This is oxygen or O2 sensors located between the bank 1 cylinder head and corresponding catalytic converter. The task of this sensor is to measure the composition of raw exhaust fumes. This is important data that helps ECU when adjusting the air-fuel mixture for optimum efficiency.

Is Bank 1 Sensor 1 Upstream? 

On all cars, bank 1 sensor 1 is an upstream oxygen sensor. You will find it on the exhaust side, closest to the bank 1 cylinder head. On in-line engines, it is easy to spot it, while on V-shaped engines, it is important to find out which is the bank 1 side. 

How to change O2 sensor Bank 1 Sensor 1? 

After locating it in your car, replacing the sensor is just the matter of undoing several bolts or unscrewing the sensor itself. However, on most cars, access can be tricky because of limited space, so you will need a special O2 sensor socket. As a preparation step, disconnect the wire plug and spray some penetrating oil onto sensor threads. When installing a new one, add some anti-seize to the threads and tighten it to the specified torque. 

Where is the Bank 1 Sensor on a Ford F150? 

Being a classic truck with a rear-wheel-drive configuration, F-150 has a longitudinally-mounted engine. Also, all newer F-150 models have V-shaped engines. Despite their differences in capacity and number of cylinders, they all have a bank 1 sensor 1 on the passenger side. 

Where is Bank 1 sensor 1 on a Toyota?

As with any other vehicle, this depends on the engine type and drivetrain configuration. On most in-line engines, the Bank 1 sensor 1 will be located at the engine's front side, near the cylinder head. On most front-wheel-drive models with V6 engines, this sensor will be on the backside against the firewall. Most rear-wheel-drive cars and pickups will have this sensor on the passenger side.  

Can you clean a Bank 1 sensor 1 O2 sensor?

The O2 sensor's core is a special sensing element inside a shell with a series of holes around it. Although it is possible to remove build-ups using a brush from the protective shell, this will not clean the sensing element itself. There are special solutions that can be used for this purpose, but their performance is not that reliable.