1994 Chevrolet Astro V6 4.3L Upstream O2 Oxygen Sensor ACDelco AFS75

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Hi, I'm Don from 1A Auto. I hope this how-to video helps you out, and the next time you need a part for your vehicle, think of 1AAuto.com. Thanks.

In this video, we're going to show you how to replace a downstream O2 sensor on this 2002 Chevy Suburban. We show you on the passenger's side, but the driver's side has a similar procedure. You'll need a new downstream O2 sensor from 1AAuto.com, a flat blade screwdriver, a 7/8" wrench, and some wire cutters.

To start off, we're going to show you where your O2 sensors are. On this side, on the driver's side, it's the Bank 1, Sensor 1. This is Bank 1, Sensor 2. This is on the passenger side: Bank 2, Sensor 1 and Bank 2, Sensor 2. Both Sensor 1s are your upstream, and both Sensor 2s are your downstream. We're going to do Bank 2, Sensor 2, which is the passenger side downstream O2 sensor.

You just want to pry out this clip, pull the harness down, pull out that pin, then pry up the tab, and disconnect the harness. Use your wire cutters to cut off the harness connector at the bottom of your O2 sensor. We do this so we can get the closed end of the wrench onto the O2 sensor. Now slide your 7/8-inch wrench into place and using another wrench for leverage you want to pry it and break it free, and then twist it out the rest of the way. We'll fast-forward as Don does this.

Obviously, we have the vehicle up on a lift, but, actually, there's enough clearance on these vehicles that you don't even need to jack them up to do this. On the left is the old downstream O2 sensor; on the right is the new one from 1AAuto. You can see they're going to fit exactly the same.

Take your new downstream O2 sensor, feed it into place, and just twist it in. I'll fast-forward as Don does this and then tightens it up with the wrench. Now just reconnect your harness and then push that pin back into place. Then re-clip the harness to the vehicle. You're all set.

We hope this video helps you out. Brought to you by www.1AAuto.com, your source for quality replacement parts and the best service on the Internet. Please feel free to call us toll-free, 888-844-3393. We're the company that's here for you on the Internet and in person.

Hi, I'm Mike from 1A Auto. We've been selling auto parts for over 30 years. We're dedicated to delivering quality auto parts, expert customer service, fast and free shipping, all backed by our 100% satisfaction guarantee. Visit us at 1AAuto.com, your trusted source for quality auto parts.

In this video I have a couple of oxygen sensors with me. While there are some aesthetic differences here, the wire lengths are a little different, the actual body and tip of the sensor are a little different, the threads and gasket are the same, and on the other end the connections are actually the same. I can plug these into either position on our vehicle. But if I had to ask you which one's upstream and which one's downstream, you probably can't tell just from looking at them. That's true of most oxygen sensors. The way you determine whether or not an O2 sensor is upstream or downstream is all done visually.

Your oxygen sensor position can be determined relative to your catalytic convertor. As the name suggests, upstream sensors will be located upstream or ahead of, in front of, above, closer to the engine than your catalytic convertors. This means that they see the exhaust gasses first. They then go through the catalytic convertor and to the downstream oxygen sensor, which will either be located in the catalytic convertor like our vehicle here, or after the catalytic convertor to monitor the gasses coming out of the cat and make sure that it's being efficient relative to the readings of the upstream O2 sensor.

The other determination you need to make is bank one versus bank two. Determining which bank is which can be done by looking at a picture of your vehicle's firing order. Whichever bank contains cylinder one is going to be bank one, and the other one, regardless of whether or not cylinder two is in it, is going to be bank two by default. These banks are true of V engines like V8s, V6s, and flat engines like Porsches and Subarus that have individual banks.

On inline four-cylinder engines, as long as they have one exhaust manifold like a Jeep four-liter or a four-cylinder Honda engine, you'll only have one bank with an upstream and downstream O2 sensor. There will be no bank two on the engine.

On our vehicle here, this is the passenger side, which we've already determined from the firing order is bank one. We have our upstream sensor here closest to the engine ahead of the cat. Then we have our downstream or sensor two here inside of the catalytic convertor. This could also be located somewhere after the cat. Here I have my two sensors for the vehicle. While they are aesthetically different, we can now tell this is my upstream sensor because it looks just like the upstream sensor I have up there. This is my downstream sensor. Now that we know which one's which, we can order the right part, correct the problem, and fix you up right.

Thanks for watching. Visit us at 1AAuto.com for quality auto parts, fast and free shipping, and the best customer service in the industry.

Brought to you by 1AAuto.com, your source for quality replacement parts and the best service on the Internet.

Hi, I'm Don from 1A Auto. I hope this how-to video helps you out, and the next time you need a part for your vehicle, think of 1AAuto.com. Thanks.

In this video, we're going to show you how to replace an upstream O2 sensor on this 2002 Chevy Suburban. We show you on the passenger's side, but the driver's side is a similar procedure. The items you'll need for this include a new upstream O2 sensor from 1AAuto.com, a flat blade screwdriver, 7/8 inch wrench, and a pair of wire cutters.

To start off, we're going to show you where your O2 sensors are. The driver's side is bank one and this is bank one, sensor one and bank one, sensor two. On the passenger's side, you have bank two, sensor one and bank two, sensor two. Both sensor ones are the upstreams, and both sensor twos are the downstreams. We're going to show you on bank two, sensor one.

The harness is on the other side of this frame. You just want to just clip the harness pin, pull the harness free, and disconnect it. Just pull the tab, pull it free, and then you want to pry at this clip with a flat blade screwdriver and separate it. You want to pull your O2 sensor wire free from that clip and then cut the harness connector at the end from the harness.

Two notes: this is going to allow you to get the closed end of the wrench over the harness and also you can do this without having to jack up the vehicle; the clearance is good enough on these vehicles to get underneath.

Now, using your 7/8 inch wrench, just slide it up into place on the O2 sensor, and, using another wrench for leverage, just break it free. Then loosen it up the rest of the way with the wrench and remove it. We'll just fast-forward as Don does this.

On the left is the old upstream O2 sensor; on the right is the new one from 1A Auto. You can see they're going to fit exactly the same. Feed your new upstream O2 sensor into place and just twist it in. We'll fast-forward as Don does this and then tightens it up with the wrench.

Now put your harness back over the frame and reconnect it into that clip. Then pull it over the other side, reconnect the harness, and push that pin back into place. Then re-clip the harness up here into this bracket, and you're all set.

We hope this video helps you out. Brought to you by www.1AAuto.com, your source for quality replacement parts and the best service on the Internet. Please feel free to call us toll-free, 888-844-3393. We're the company that's here for you on the Internet and in person.