Replacing Both Upstream o2 Sensors...location?

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Jun 7, 2012 | 10:19 PM

bzauche

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Joined: Sep 2011

Posts: 311

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From: Cumming/Dahlonega, Georgia

Year: 2001

Model: Cherokee

Engine: 4.0L

Replacing Both Upstream o2 Sensors...location?

Hey all,

One of my weekend projects is going to be replacing both of my upstream oxygen sensors. I already have the parts, but I need to know which ones are the upstream sensors. I have a 2001 with the pre-cats and 4 sensors. In the FSM picture below, am I replacing sensors 1 and 2?

Thanks!

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Name: ScreenShot2012-06-07at111242PM.jpg
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Size: 167.1 KB

Jun 8, 2012 | 12:25 AM

Radi

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Joined: Apr 2012

Posts: 5,302

Likes: 23

From: Wisconsin

Model: Cherokee

1&2

Jun 8, 2012 | 08:09 AM

bzauche

Thread Starter

Seasoned Member

Joined: Sep 2011

Posts: 311

Likes: 0

From: Cumming/Dahlonega, Georgia

Year: 2001

Model: Cherokee

Engine: 4.0L

Quote:

Originally Posted by Radi

1&2

Thanks! That's what I thought, just wanted to make sure. Is it safe to assume that 1 is considered the "front" and 2 is considered the "rear" sensor?

Jun 8, 2012 | 08:15 AM

USMCgunrock

Seasoned Member

Joined: Feb 2011

Posts: 276

Likes: 7

From: NJ/NY

Year: 2001

Model: Cherokee

Engine: I6

Quote:

Originally Posted by bzauche

Thanks! That's what I thought, just wanted to make sure. Is it safe to assume that 1 is considered the "front" and 2 is considered the "rear" sensor?

Yup! And invest on an o2 ratchet socket. Makes life a little simpler!

Jun 8, 2012 | 11:43 AM

Bustedback

CF Veteran

Joined: Feb 2010

Posts: 12,367

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From: Oroville, CA

Year: 1995

Model: Grand Cherokee

Engine: 4.0 with all of the noise and clatter

Why are you replacing the sensors? Did they test bad, or do you just have some extra money to spend?

Jun 8, 2012 | 12:24 PM

bzauche

Thread Starter

Seasoned Member

Joined: Sep 2011

Posts: 311

Likes: 0

From: Cumming/Dahlonega, Georgia

Year: 2001

Model: Cherokee

Engine: 4.0L

Quote:

Originally Posted by USMCgunrock

Yup! And invest on an o2 ratchet socket. Makes life a little simpler!

Thanks!

Quote:

Originally Posted by Bustedback

Why are you replacing the sensors? Did they test bad, or do you just have some extra money to spend?

I haven't tested them, but they haven't been replaced in 166k miles, so I figure it's time to swap them out. Just because I don't have a CEL doesn't mean they're not bad, either.