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Oxygen sensors


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firepop5's Avatar
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June 15th, 2009, 10:07 PM   #1  
Oxygen sensors

On a 2001 Impala with 3.4L, how many oxygen sensors are there and where are they located?

 
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June 16th, 2009, 12:32 AM   #2  
You have 2.

One before the cat & one after the cat on your exaust pipes.

I cant find a picture but here is what the book says...



Removal & Installation

Upstream HO<SUB>2</SUB> S1

To Remove:


NOTE: If the engine temperature is lower than 120 F (48 C), the HO<SUB>2</SUB> S1 sensor may be difficult to remove. Excessive force could possibly damage the threads in the exhaust manifold.
  1. If necessary remove the fuel injector cover.
  2. Disconnect the HO<SUB>2</SUB> S1 sensor electrical connector.
  3. Using an oxygen sensor removal tool carefully remove the heated oxygen sensor.
To Install:
  1. Coat the threads of the oxygen sensor with anti-seize compound
  2. Install the HO<SUB>2 </SUB>S1 sensor. Tighten the HO<SUB>2</SUB> S1 sensor to 30 ft lb (41 Nm).
  3. Connect the HO<SUB>2</SUB> S1 sensor connector.
  4. If removed, install the fuel injector cover.
Downstream HO<SUB>2</SUB> S2

To Remove:


NOTE: If the engine temperature is lower than 120 F (48 C), the H0<SUB>2</SUB> S2 sensor may be difficult to remove. Excessive force could possibly damage the threads in the exhaust pipe.
  1. Raise and safely support the vehicle.
  2. Disconnect the HO<SUB>2</SUB> S2 electrical connector.
  3. Using an oxygen sensor tool carefully remove the H<SUB>2</SUB>0 S2.
To Install:
  1. Coat the threads of the HO<SUB>2</SUB> S2 with anti-seize compound.
  2. Using an oxygen sensor tool install the HO<SUB>2</SUB> S2.
  3. Tighten the sensor to 30 ft lb (41 Nm).
  4. Connect the HO<SUB>2</SUB> S2 sensor electrical connector.
  5. Lower the vehicle.

 
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June 16th, 2009, 4:41 PM   #3  
Thanks alot!

 
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June 16th, 2009, 6:45 PM   #4  
Posted By: firepop5 Thanks alot!
you bet.

 
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June 16th, 2009, 9:04 PM   #5  
the upstream o2 sensor is on the rear exhaust manifold.

may i ask what you're inquiring about these for?

 
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June 17th, 2009, 12:53 PM   #6  
This is my brother's car and he asked me for some help. He had his computer scanned at a parts store and they told him his O2 sensors were bad. Wanted to have as much info as possible before I start troubleshooting since I'm not familiar with the car. If I decide to swap out the sensors, is AC Delco worth the extra money or are Bosch replacements OK?

 
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June 17th, 2009, 1:06 PM   #7  
What code(s) did it throw? They both may not be bad, it could even be something else.

 
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June 20th, 2009, 12:36 PM   #8  
I got to see my brothers car today. The "Service vehicle soon" message is showing on dashboard. I scanned the OBD2 connector and got no codes. I would suspect if his O2 sensors were bad, the "check engine" light would come on instead of the service vehicle soon light anyway. I don't know why the shop he visited said he needed Os sensors. I saw their diagnostic report, and there are no codes listed, just a quote to change the O2 sensors.

According to his owners manual, if the service vehicle soon message appears, you must visit the dealer, or there is a problem with a trunk safety system. I'm pretty sure the car doesn't have this safety system on it.

After a little research I suspect the Body Control Module (BCM) is turning on the light. Does this BCM have a diagnostic connection and would an Auto Zone or similar place be able to diagnose or pull codes?


Last edited by firepop5; July 3rd, 2009 at 7:41 PM.
 
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July 5th, 2009, 7:20 AM   #9  
no, autozone or any other parts store wont be able to read BCM codes. you'll most likely have to got to a dealer to get those codes as those codes can only br read with a tech II scanner. the only place i've seen with a tech II is a dealer. you dont have to take it to a chevy dealer, any GM dealer will have a tech II scanner.

 
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July 6th, 2009, 12:43 PM   #10  
Ared the BCM codes also accessed from the OBD2 terminal under the dash?

 
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