Are you struggling to figure out which O2 sensor or ignition coil you should replace?
You are not alone! Using a diagnostic scanner can really help you troubleshoot a car’s issues efficiently, but sometimes it can be difficult to know what the trouble code you read from the scanner actually means.
One of these things is if you get a trouble code saying bank 1 or bank 2, sensor 1 or sensor 2 in the last sentence of the trouble code data. But, It is actually not that difficult! Let’s find out what it means!
What is Bank 1 vs. Bank 2?
Bank 1 and bank 2 simply refer to either side of the engine. Bank 1 is on the side with cylinder 1. Bank 2 is the side with cylinder 2. Most commonly, Bank 1 is towards the front of the car if it has a transverse engine.
The easiest way to discover the right cylinder bank is to check your car’s repair manual. You can also try to find any stamps on the cylinder block or head for any cylinder numbers.
The front of the engine is the part where the crankshaft pulley is. The side nearest the front is not the front of the engine.
You can’t simplify it and say that bank 1 is on the driver’s side or vice versa, because different engines can have cylinder 1 on different sides. We drive on different sides globally, so it’s just confusing and misleading to guess which side bank 1 or bank 2 is on.
- Bank 1 is the side with cylinder number 1 (Cylinders 1 – 3 – 5 – 7 etc.)
- Bank 2 is the side with cylinder number 2 (Cylinders 2 – 4 – 6 – 8 etc.)
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What is Sensor 1 & 2?
The sensor number tells us where on the exhaust system the O2 sensor or the exhaust temperature sensor is installed.
The 1st sensor is located closest to the engine, and the last is located toward the rear of the exhaust system.
Generally, if we are talking about O2 sensors:
- Sensor 1 = Before Catalytic converter Front (Upstream O2 sensor)
- Sensor 2 = After Catalytic Converter Rear (Downstream O2 sensor)
Some diesel engines have many exhaust temperature sensors, and they can use sensors 1 – 2 – 3 – 4, etc. In this case, sensor 1 is nearest to the engine, and the last sensor is in the exhaust system’s rear.
Are bank 1 and bank 2 sensors the same?
In most cases, the sensors on bank 1 or bank 2 are the same. However, this is completely dependent on the car model and which sensor we are talking about. Check a repair manual or ask a dealer for the right answer for your car model.
Is bank 1 driver or passenger side?
No. Bank 1 refers to the side of the engine with cylinder 1. While it is often true that bank 1 is located on the driver’s side, this is not always the case. You will only waste your money by using this method instead of checking it properly.
Is bank 2 front or rear?
The bank has nothing to do with the front or back of the engine, even if your engine is transversely mounted. Bank 1 is the side with cylinder one and bank 2 is the side with cylinder two. Sensor 1 and sensor 2 are telling us if it’s the front or rear O2 sensor.
Is bank 1 on the exhaust or intake side?
Bank 1 or Bank 2 has nothing to do with the exhaust or intake side, so it all depends on what engine you have. Bank 1 is the side with cylinder 1 and bank 2 is the side with cylinder 2.
All the information about different banks and sensor locations can be confusing for most people, but it’s actually quite logical if you just know the basics. So to answer most of the questions people have about different banks and sensors, we’re going to summarize the different O2 sensor locations here:
Where is the Bank 1 Sensor 1 Located?
Bank 1 Sensor 1 is the first sensor closest to the engine (Upstream) on Bank 1. Bank 1 means it is at the side of the engine with cylinder numbers 1, 3, 5, 7, etc.
Where is the Bank 1 Sensor 2 Located?
Bank 1 Sensor 2 is the second sensor on the engine’s exhaust pipe (Downstream) on Bank 1, usually behind the catalytic converter. Bank 1 means it is at the engine side with cylinder numbers 1, 3, 5, 7, etc.
Where is the Bank 2 Sensor 1 Located?
Bank 2 Sensor 1 is the first sensor closest to the engine (Upstream) on Bank 2. Bank 2 means it is at the side of the engine with cylinder numbers 2, 4, 6, 8, etc.
Where is the Bank 2 Sensor 2 Located?
Bank 2 Sensor 2 is the second sensor on the engine’s exhaust pipe (Downstream) on Bank 2, usually behind the catalytic converter. Bank 2 means it is at the engine side with cylinder numbers 2, 4, 6, 8, etc.
I hope you enjoyed this article and now have the knowledge to determine which O2 sensor you should replace to fix your car issue. Don’t forget to follow us on our YouTube channel!
Learn more:
- How to Bypass Oxygen Sensors – Can & Should You Do it?
- 15 Types of Car Sensors (& What They Do)
- 8 Symptoms of a Bad MAF Sensor
Categories: Exhaust, Troubleshooting
