Where is the oxygen o2 sensor located on 2004 impala bank 1

The 2004 Ford Freestar SEL is equipped with a V6 engine, and it typically has two heated oxygen sensors (HO2S) due to its dual exhaust system. These sensors are also commonly referred to as oxygen sensors or O2 sensors. The specific details may vary depending on the exact engine and exhaust configuration of your vehicle.

1. Bank 1 Sensor 1 (B1S1): This is the upstream oxygen sensor located before the catalytic converter on the side of the engine where cylinder 1 is located. It monitors the oxygen content in the exhaust gases before they enter the catalytic converter.
2. Bank 2 Sensor 1 (B2S1): This is the upstream oxygen sensor located before the catalytic converter on the side of the engine where cylinder 2 is located. Similar to B1S1, it monitors the oxygen content in the exhaust gases before they reach the catalytic converter.

These sensors play a crucial role in monitoring the air-fuel mixture and helping the engine control module (ECM) adjust fuel delivery for optimal performance and emissions.
Please note that vehicle specifications can vary, and it's always best to refer to your vehicle's owner's manual or consult with a qualified mechanic to get accurate and specific information about the number and location of oxygen sensors in your particular 2004 Ford Freestar SEL.

code p 0136 refers to heated oxygen sensor (HO2S) 2 bank 1 ---circuit malfunction===causes ---heating inoperative ---wiring---HO2S--- ECM
also refers to oxygen sensor (O2S0 2 bank 1---circuit malfunction===causes --- wiring---O2S ---ecm
it also refers to heated oxygen sensor (HO2S) 2 bank 1 ---no signal===causes ---wiring --- HO2S---
code p 0137 refers to HO2S 2 bank 1 ---low voltage -===causes --exhaust leak---wiring short to ground ---HO2S--- ECM
it also refers to O2S 2 bank 1---low voltage ===causes exhaust leak---wiring short to ground ---O2S ---ECM
to set you up here-- there are 4 oxygen sensors in the system
2 are heated oxygen sensors (HO2S) on in each exhaust manifold or exhaust pipe before the cat converter and
2 oxygen sensors (O2S) -- one in each exhaust pipe after the cat converters
heated oxygen sensors have 4 wires and O2S sensors normally only 2 wires
it is more that possible that you changed the wrong sensors and in the process damaged the delicate wires with the incorrect spanner being used

There is 4 senors the bank 1 sensor 1 is located in front of the LH (Drivers side) catalytic converter
Hope this helps

Proper terminology is Air/Fuel Ratio (A/F) Sensor Bank 1, Sensor 1. It's not an Oxygen sensor, per se. It is a wide range oxygen sensor. It is located in the top of the Bank one Catalytic converter which is at the firewall or windshield bank of the engine. There is no exhaust manifold. The cat converter bolts directly to the head. The A/F sensors screw into tops of the converters.

for p0171, try:
In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
Inspect all vacuum and PCV hoses, replace if necessary
Check for a dirty fuel filter and proper fuel pressure
for p0420, try:

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

try this
ALLDATA Editor's Note: Always verify #1 cylinder location prior to diagnosis and repair.

- Cylinder bank number one is the bank that contains number one cylinder.


See: Firing Order


View & Print Options
Cylinder #1 on left side.

View & Print Options
Cylinder #1 on right side.

- The first oxygen sensor in cylinder bank # 1 is numbered O2 Sensor 1/1.
- The second oxygen sensor in cylinder bank # 1 is numbered O2 Sensor 1/2.
- A third oxygen sensor in cylinder bank # 1 would be numbered O2 Sensor 1/3.
- The first oxygen sensor in cylinder bank # 2 is numbered O2 Sensor 2/1.
- The second oxygen sensor in cylinder bank # 2 is numbered O2 Sensor 1/1.



- If a V-6 or V-8 vehicle only uses one downstream Heated Oxygen Sensor (HO2S) it is numbered O2 Sensor 1/2, even if it uses two upstream HO2S.
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BANK 1 UP STREAM OXYGEN SENSOR LOCATION IS LOCATED ON THE REAR EXHAUST MANIFOLD.

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).

Grand Cherokee oxygen sensor locations for 4.0 and 4.7 engines







Four wires (circuits) are used on each O2 sensor:

• 12–volt feed circuit for the sensor heating element
• Ground circuit for the heater element
• Low-noise sensor return circuit to the PCM
• Input circuit from the sensor back to the PCM to detect sensor operation

O2S Sensor removal Never apply any type of grease to the oxygen sensor electrical connector, or attempt any soldering of the sensor wiring harness.
WARNING: THE EXHAUST MANIFOLD, EXHAUST PIPES AND CATALYTIC CONVERTER(S) BECOME VERY HOT DURING ENGINE OPERATION. ALLOW ENGINE TO COOL BEFORE REMOVING OXYGEN SENSOR.
1. Raise and support vehicle.
2. Disconnect O2S pigtail harness from main wiring harness.
3. If equipped, disconnect sensor wire harness mounting clips from engine or body.
CAUTION: When disconnecting sensor electrical connector, do not pull directly on wire going into sensor.
4. Remove O2S sensor with an oxygen sensor removal and installation tool.

02S Sensor installation
Threads of new oxygen sensors are factory coated with anti-seize compound to aid in removal. DO NOT add any additional anti-seize compound to threads of a new oxygen sensor.
1. Install O2S sensor. Tighten to 22 ft. lbs. (30 N·m) torque.
2. Connect O2S sensor wire connector to main wiring harness.
3. If equipped, connect sensor wire harness mounting clips to engine or body. When Equipped: The O2S pigtail harness must be clipped and/or bolted back to their original positions on engine or body to prevent mechanical damage to wiring.


Hope thats help (remember comment and rated this).

the O2 sensor for bank one sensor one is located between the catalytic converter and the engine in the exhaust head pipe. see photo of your engine cylinder layout, the sensor u want to replace is the one at the cylinder #1 bank on right.