Question about 2002 Toyota Tacoma

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How many air/fuel or oxygen sensors are on the 2002 Prerunner 4cylinder?

Thank you. The stealership says I have 3; one on the exhaust manifold, called the air/fuel ratio sensor (basically and advanced o2 sensor) one o2 sensor just before the first CAT and one o2 sensor just after the last CAT. I just looked at the exhaust system real close, there is no sensor on or near the exhaust manifold. Are they lying or just incompetent?

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The air-fuel sensor is located BELOW the manifold, on the side of the head pipe. You would need to be under the vehicle to see it.
That sensor is commonly called "bank one/sensor one".

Posted on Sep 09, 2008


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Can anyone tell me where the oxygen sensor is located on a 2012 chevrolet equinox 4cylinder

heated oxygen sensors(HO2S) are located in the exhaust manifold or exhaust pipe before the cat converter
oxygen sensors (O2S) are located after the cat converter
they are not the same items and do different jobs

Mar 12, 2017 | Chevrolet Cars & Trucks

1 Answer

Which O2 sensor is needed for The code P1135 tOYOTA aVALON 2002

code p 0035 refers to heated oxygen sensor(HO2S)--LH front ---heater circuit malfunction===causes ---wiring--HO2S--air induction system---fuel pressure ----injector/s---ECM
heated oxygen sensors are always located in the exhaust manifold/pipe before the cat converter
they control the fuel/air ratio parameters for the ECM to get best burn of the mixture
Oxygen sensor (O2) is always after the cat converter and sets the parameters for the cat burn off

Dec 10, 2016 | 2002 Toyota Avalon

1 Answer

Where are o2 sensors location

One would need the year, make, model, and engine size to tell you exactly where they are and how many.

O2 sensors are always in the exhaust stream, either in the exhaust manifold that is attached to the engine, or in the exhaust piping after the exhaust manifold. Some models have one for each bank of the engine, and some have only one sensor to monitor oxygen content. These engine sensors that the computer uses to "fix" or adjust the air/fuel ratio are called the upstream oxygen sensors. If the car is equipped (as most are today) with an oxygen sensor after the catalytic converter, this is called a downstream oxygen sensor. They are the same and do the same thing, but the downstream sensor is only used to monitor the efficiency of the converter. The upstream sensor(s) are what the computer reads to adjust or "trim" the fuel delivery.

So some older cars have only one o2 sensor. Not far from the engine in the exhaust stream. Some newer cars with dual exhaust (2 converters) may have four o2 sensors. 1 for each bank of the engine and 1 behind each catalytic converter. A 2005 Buick Century with a 3.1L engine, for instance, has only two o2 sensors: one (upstream) in the exhaust down pipe, and one (downstream) just behind the catalytic converter.

Aug 16, 2014 | Cars & Trucks

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2002 toyota avalon engine check light on P0078 and P007C

P0050 HO2S Heated Oxygen Sensor -Control Circuit (Bank 2 Sensor 1)

P0051 HO2S Heated Oxygen Sensor -Control Circuit Low (Bank 2 Sensor 1)

P0052 HO2S Heated Oxygen Sensor -Control Circuit High (Bank 2 Sensor 1)

P0053 HO2S Heated Oxygen Sensor -Resistance (Bank 1 Sensor 1)

P0054 HO2S Heated Oxygen Sensor -Resistance (Bank 1 Sensor 2)

P0055 HO2S Heated Oxygen Sensor -Resistance (Bank 1 Sensor 3)

P0056 HO2S Heated Oxygen Sensor -Control Circuit (Bank 2 Sensor 2)

P0057 HO2S Heated Oxygen Sensor -Control Circuit Low (Bank 2 Sensor 2)

P0058 HO2S Heated Oxygen Sensor -Control Circuit High (Bank 2 Sensor 2)

P0059 HO2S Heated Oxygen Sensor -Resistance (Bank 2 Sensor 1)

P0060 HO2S Heated Oxygen Sensor -Resistance (Bank 2 Sensor 2)

P0061 HO2S Heated Oxygen Sensor -Resistance (Bank 2 Sensor 3)

P0062 HO2S Heated Oxygen Sensor -Control Circuit (Bank 2 Sensor 3)

P0063 HO2S Heated Oxygen Sensor -Control Circuit Low (Bank 2 Sensor 3)

P0064 HO2S Heated Oxygen Sensor -Control Circuit High (Bank 2 Sensor 3)

P0065 Air Assisted Injector -Range/Performance

P0066 Air Assisted Injector -Circuit Malfunction or Circuit Low

P0067 Air Assisted Injector -Circuit High

P0068 (MAP) Manifold Absolute Pressure /(MAF) Mass Air Flow - Throttle Position


P0069 (MAP) Manifold Absolute Pressure / (BARO)Barometric Pressure Correlation

P0070 Ambient/Outside Air Temperature Sensor -Circuit Malfunction

P0071 Ambient/Outside Air Temperature Sensor -Range/Performance Problem

P0072 Ambient/Outside Air Temperature Sensor -Circuit Low Input

P0073 Ambient/Outside Air Temperature Sensor -Circuit High Input

P0074 Ambient/Outside Air Temperature Sensor -Circuit Intermittent

P0075 Intake Valve Control Solenoid Circuit Malfunction (Bank 1)

P0076 Intake Valve Control Solenoid Circuit Low (Bank 1)

P0077 Intake Valve Control Solenoid Circuit High (Bank 1)

P0078 Exhaust Valve Control Solenoid Circuit Malfunction (Bank 1)

P0079 Exhaust Valve Control Solenoid Circuit Low (Bank 1)

P0080 Exhaust Valve Control Solenoid Circuit High (Bank 1)

P0081 Intake valve Control Solenoid Circuit Malfunction (Bank 2)

P0082 Intake Valve Control Solenoid Circuit Low (Bank 2)

P0083 Intake Valve Control Solenoid Circuit High (Bank 2)
P0084 Exhaust Valve Control Solenoid Circuit Malfunction (Bank 2)

Mar 22, 2013 | 2002 Toyota Avalon

1 Answer

0152 coed

P0152 P0152 - O2 Sensor Circuit High Voltage Bank 2 Sensor 1Possible causes - Faulty Front Heated Oxygen Sensor Bank 2
- Intake air leaks may be faulty
- Exhaust gas leaks
- Front Heated Oxygen Sensor Bank 2 harness is open or shorted
- Front Heated Oxygen Sensor Bank 2 circuit poor electrical connection
- Inappropriate fuel pressure
- Faulty fuel injectors
eplacing the Front Heated Oxygen Sensor Bank 2 usually takes care of the problem
Symptoms- Engine Light ON (or Service Engine Soon Warning Light)
- High Fuel Consumption
- Excessive Smoke from Exhaust P0152 Description The front heated oxygen sensor (or O2 sensor 1) is placed into the exhaust manifold. It detects the amount of oxygen in the exhaust gas compared to the outside air. The heated oxygen sensor 1 has a closed-end tube made of ceramic zirconia. The zirconia generates voltage from approximately 1V in richer conditions to 0V in leaner conditions. The heated oxygen sensor 1 signal is sent to the Engine Control Module (ECM). The ECM adjusts the injection pulse duration to achieve the ideal air-fuel ratio. The ideal air-fuel ratio occurs near the radical change from 1V to 0V.

Mar 19, 2013 | 2005 Dodge Ram 1500

1 Answer

My 2000 Toyo. Tacoma Prerunner TRD V6, truck Failed smog due to the part #3 Functional Computer Tests due to an erased MIL. But had passed the Visual Inspection, and Emissions. So i bought a Code reader...

there are 2 sensors in the system
one is a heated oxygen sensor (HO2S) in the exhaust manifold / pipe before the cat converter that reports the exhaust gas composition to the ECM so that fuel/ air ratios can be adjusted
if that one is faulty it is most likely the reason for running lean or rich
the second sensor is the oxygen sensor (O2) which is after the cat converter and reads the results of the cat converter cleaning the exhaust
you may have to replace both the sensors to get a clearance or replace the cat converter as well as the HO2S unit

Jun 02, 2017 | 2000 Toyota Tacoma PreRunner

3 Answers

Where is the oxygen sensor bank 1 sensor 1?

From the 2002 Oldsmobile Alero manual:
A device found in the exhaust manifold, which generates a small voltage dependent on the amount of oxygen present in the exhaust stream, used as a signal to the engine-control computer to determine the amount of fuel necessary to maintain a proper air/fuel ratio.
What this means to me is search the exhaust manifold for it - its screwed into it.
Unscrew it with a specialty oxygen sensor socket (a slotted 7/8-in hex socket) - available for
$10 at any parts store. This is likely the HO2S (heated oxygen sensor) Bank 1 Sensor 1, since
it is before the catalytic converter, the second oxygen sensor (Bank 1, Sensor 2) should
be the one located after the catalytic converter.

P0130 - HO2S-11 (Bank 1 Sensor 1) Circuit Closed Loop Performance
P0131 - HO2S-11 (Bank 1 Sensor 1) Circuit Low Input
P0132 - HO2S-11 (Bank 1 Sensor 1) Circuit High Input
P0133 - HO2S-11 (Bank 1 Sensor 1) Insufficient Activity
P0135 - HO2S-11 (Bank 1 Sensor 1) Heater Circuit Malfunction

Note the P0131 can be also be caused by a bad MAP (Manifold Absolute Pressure) sensor,
so yank the MAP sensor and check the computer for a lean fuel condition (P0131=low input).

Mar 24, 2011 | 2002 Oldsmobile Alero

2 Answers

My car burns gas very fast. where is the 02 sensor located? do i need a calib cabreter?

02 sensors are located in the exhaust the upstream ones are close to the engine in the rear exhaust manifold (for 6 cylinders) and at the front exhaust (for 4 cylinder). The downstream ones are behind the catalytic converter. Check to make sure the fuel pressure regulator on the to of the engine isn't leaking. Replace the air and fuel filter could be plugged. Check the coolant level in both the rad and the reservoir they are notorious for intake manifold and head gasket leaks for 6 cylinders. There aren't many calibration updates for this vehicle relating to fuel consumption.

Jan 30, 2011 | 2000 Oldsmobile Alero

1 Answer

What does trouble code P0171 for a 2002 Buick Park Avenue mean?

Trouble Code: P0171 (3.8L V6 VIN 1 Auto)
Fuel Trim System Lean (Bank 1) Print this code dataprint_icon_codes.gif Number of Trips to Set Code: 2
OBD II Monitor Type: CCM Details
Indicators: MIL Details
Trouble Code Conditions:
DTC P0101-P0103, P0107, P0108, P0121-P0123, P0130-P0138, P0140, P0141, P0201-P0206, P0300, P0401-P0405, P0410, P0440-P0446, P0506, P0507, P1404 or P1441 not set, engine started, vehicle driven at less than 82 mph at 550-4000 rpm, BARO sensor over 70 kPa (10.1 psi), ECT sensor from 68-230ºF, IAT sensor from 64-158ºF, MAF sensor from 2.8-150 gm/s, MAP sensor from 16-105 kPa (2.6-15.2 psi), fuel level over 10%, and the PCM detected the Long Term fuel trim value was more than +20% for 6 seconds. The PCM controls the air/fuel metering system to good overall fuel economy, driveability, and emission control. During open loop, the PCM determines fuel delivery based on sensor signals, without the oxygen sensor input. During closed loop, the PCM adds oxygen sensor inputs to calculate Short and Long term fuel trim fuel delivery adjustments. Short Term fuel trim values change rapidly in response to changes in the oxygen sensor signals. Long Term fuel trim makes coarse adjustments in order to maintain an air/fuel ratio of 14.7:1.

Possible Causes:
  • Air leaks in intake manifold, exhaust pipes or exhaust manifold
  • Fuel control sensor is out of calibration (ECT, IAT or MAF)
  • Low fuel pressure (fuel filter clogged, pressure regulator failure)
  • One or more injectors restricted or pressure regulator has failed
  • HO2S element is contaminated, deteriorated or has failed
  • Vacuum hose is disconnected, broken, leaking or loose

Troubleshooting:2002 Buick Park Avenue, 3.8L, P0171

Nov 01, 2009 | 2002 Buick Park Avenue

1 Answer


Not just a faulty catalytic converter will trigger this code. Many other issues can trigger this code.

  • Leaded fuel was used where unleaded was called for
  • An oxygen sensor is not reading (functioning) properly
  • The engine coolant temperature sensor is not working properly
  • Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe
  • Delayed spark timing
  • The oxygen sensors in front and behind the converter are reporting too similar of readings
Possible solutions:
  • Check for exhaust leaks at the manifold, pipes, catalytic converter.
  • Replace Coolant Temperature Sensor
  • 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 the catalytic converter
  • Have timing adjusted

Aug 25, 2009 | 2002 Toyota Camry

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