Question about 2005 Chevrolet Impala
I have a 2002 Impala with 3.8L, and just replaced my Bank1 O2.
It is located between the firwall and the middle of the engine, straight down past the spark plugs. Maybe 12 inches from the top of the engine.
As I recall the plug for the sensor is clipped to a bracket at about spark plug level.
I recommend using the crow foot style wrench to remove and install.
Posted on Jan 07, 2011
There are 2 oxygen sensors on the 2004 Impala, located under the car near the CAT converter.
Jack up the passenger side or onto ramps to make easier acess.
Posted on Feb 03, 2011
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Posted on Jan 02, 2017
B1 means the sensor is located on the same bank of the engine that has the #1 cylinder. B2 is located on the opposite bank.
S1 means the sensor is located BEFORE the catalytic converter
S2 means the sensor is located AFTER the catalytic converter
You didn't say which engine you have, so I've included the diagrams of both 4 cyl and 6 cyl so you can see the banks
Posted on Oct 20, 2009
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Check for exhaust leaks at the manifold, pipes, catalytic converter. Repair as required.
Use a scope to diagnose the oxygen sensor operation (Tip: The oxygen sensor in front of the catalytic converter normally has a fluctuating waveform. The waveform of the sensor behind the converter should be more steady).
Inspect the downstream heated oxygen sensor (HO2), replace if necessary
Replace the catalytic converter
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Fig. Fig. 3: Oxygen sensor-4.3L engines
Fig. Fig. 4: Oxygen sensor-5.0L and 5.7L engines
Fig. Fig. 5: Oxygen sensor-7.4L engines
Oxygen sensors are always numbered like this:
Bank 1 sensor 1
Bank 2 sensor 1
Bank 1 sensor 2
Bank 2 sensor 2
Some manufacturers use a kind of shorthand that reads different, but means the same thing:
Sensor 1/1 or O2s 1/1
Sensor 2/1 or O2s 2/1
Sensor 1/2 or O2s 1/2
Sensor 2/2 or O2s 2/2
Bank 1 is always the side of the engine where cylinder number 1 is located and, of coarse, Bank 2 is the opposite side.
On a 4 cylinder engine, there is only 1 bank and it is always referred to as Bank 1.
Sensor 1 is always the upstream sensor (the one located BEFORE the catalytic converter)
Sensor 2 is always the downstream sensor (the one that is located AFTER the catalytic converter.
Hope helps (remember to rate this).
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