Is bank 1 on the o2 sensors the 1 located on the drivers side? Vehicle is a 98' GMC Safari 2wd.

Bank 1 is the bank with cylinder #1, Bank 2 is the other side of the engine. Sensor 1 is the UPSTREAM sensor located in front of the catalytic converter
Oxygen sensor location

Hi Charles,

GM products have 4 O2 sensors attached along the exhaust pipes coming off the manifold. Bank 1 is aligned to cylinder 1 on the engine which is the driver's side. Sensor 2 is the one after the convertor (Sensor 1 being the one before the convertor). Link attached for more information.

Oxygen Sensor Locations

I have changed out one of mine; quite easy, but you need a sensor wrench which you can find an any automotive store for around $15.

The part is available readily enough - link attached.

Good luck

You must have v-6 or v-8 engine , bank determents the side of the engine and on yours bank 2 is the passenger side, an sensor 1 denotes before the catalytic converter .You vehicle has three o2 sensors ,two before the cat an one after .Up stream means before catalytic converter. / downstream after the catalytic converter .

• Bank 1 is referring to the side of the motor with cylinder 1, usually the driver side. And it would be the 3rd sensor back. Its probably not dual exhaust so its just referring to the rear o2 sensor located after the catylitic converter. Hope this helps.

Bank 1 sensor 1 this is the upstream O2 sensor closes to the engine on the driver side.

try this
ALLDATA Editor's Note: Always verify #1 cylinder location prior to diagnosis and repair.

- Cylinder bank number one is the bank that contains number one cylinder.


See: Firing Order


View & Print Options
Cylinder #1 on left side.

View & Print Options
Cylinder #1 on right side.

- The first oxygen sensor in cylinder bank # 1 is numbered O2 Sensor 1/1.
- The second oxygen sensor in cylinder bank # 1 is numbered O2 Sensor 1/2.
- A third oxygen sensor in cylinder bank # 1 would be numbered O2 Sensor 1/3.
- The first oxygen sensor in cylinder bank # 2 is numbered O2 Sensor 2/1.
- The second oxygen sensor in cylinder bank # 2 is numbered O2 Sensor 1/1.



- If a V-6 or V-8 vehicle only uses one downstream Heated Oxygen Sensor (HO2S) it is numbered O2 Sensor 1/2, even if it uses two upstream HO2S.
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Hi, There are 4 sensors, 2 pre catalytic converter, 2 post. The driver side is bank 1, and the passenger side is bank 2 .The foreward one in the pipe coming from the driver side is bank1 sensor 1, the rear sensor for the driver side is bank 1 sensor 2 . The other side would be the same, but bank 2. Good luck...

bank 1 always refers to the bank that the No.1 cylinder is located and bank 2 is the other bank. Senspr 1 refers to the upstream oxygen sensor ( before the catalytic converter) sensor 2 refers to the downstream o2 sensor(after the cat) So if your No.1 cylinder is on the left side(drivers side) then your assumption is correct.

Need more information but here is where all your O2 sensors are located
Bank 1 Sensor 1 - Driver's side, before catalytic converter Bank 1 Sensor 2 - Driver's side, after catalytic converter
Bank 2 Sensor 1 - Passenger side, before catalytic converter
Bank 2 Sensor 2 - Passenger side, after catalytic converter
Thank you for using fixya and good luck

hi there HO2S BANK 1 SENSOR 3 HEATER CIRCUIT LOW . this jiberish means that its an upstream preheated oxygen switch it may need to be replaced or one of the wires could be damaged take a look there is two o2 sensors on each side the more foreward ones are upstream and the ones located towards the muffler are called downstream . first thing id do is look for a bad or melted wire on one of the upstream sensors but in capital letters is the definition for code P0043 good hunting .