Question about 2002 Toyota Camry

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Failed emmission test codes PO420, P440, PO441, PO446 whats wrong?

Do i need to replace the oxygen sensor

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Answered the other similar question

Posted on Apr 03, 2013


6 Suggested Answers

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Posted on Jan 02, 2017

  • 19 Answers

SOURCE: toyota seinna po440, po441, po446

you have to understand that there is a leak in the system other than the gas cap for the evaporative system. The system needs to be professionally closed, and smoke introduced into to find the leak, and a through component check, eg.. purge valve vapor canister vent solenoid all functioning correctly

Posted on Sep 01, 2009

  • 42 Answers

SOURCE: 2003 toyota highlander OBD code's po442/po446/po441

if the air filter was recently inspected or changed, look for the vacuum hose to be disconnected from the valve located on the air filter cover. another source may be the gas cap either loose or with the tether strap caught under it preventing a proper seal

Posted on Dec 20, 2008

  • 2989 Answers

SOURCE: 1997 toyota camry check engine light on,code po440,po420,po441,

P0420 is catalyst system efficiency below threshold (bank 1)

P0440 is evaporative emission control system malfunction

P0441 is evaporative emission control system incorrect purge flow

Posted on Mar 29, 2009

  • 1 Answer

SOURCE: 2001 Camry code po440,po441,po446 after engine

2001 camry code po440,po441,po446
what kind of problem and how can be solved

Posted on Jun 30, 2009

  • 11 Answers


The vapor pressure sensor, VSV for canister closed valve (CCV), VSV for pressure switching valve are used
to detect abnormalities in the evaporative emission control system.
The ECM decides whether there is an abnormality in the evaporative emission control system by the vapor
pressure sensor signal.
DTCs P0441 and P0446 are recorded by the ECM when evaporative emissions leak from the components
when there is a malfunction anywhere in the VSV for EVAP, the VSV
for pressure switching valve, or in the vapor pressure sensor itself.

checked basic , gas cap.

More than likely you need to take to a garage , rec. dealership
will have to perform a smoke check to see if there is a leak somewhere or wether there is a malfunction with a vac. solinoid valve(vsv)

Posted on Apr 29, 2010

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2007 tl type s where is bank 2 sensor 1 oxygen sensor located. What is the replacement number of a sensor to kill Emission p0171 Notice and light

Oxygen sensors monitor the exhaust stream, comparing the oxygen content in it to the oxygen content of ambient air. When oxygen content is low, sensor voltage is high. When oxygen content is high, sensor voltage is low. The voltage created by the sensor is sent to the DME (engine control module) to help maintain a proper fuel mixture. The mixture preparation is used to keep the catalytic converters running at peak efficiency. The oxygen sensors used in E60 models covered in this article has four wires. Two of which are for oxygen sensor heating and two for the signal. The heater is used to get the sensor online faster. Previously, exhaust heat was used. One wire supplied a ground to the sensor for the signal, and the other was for the sensor signal.
Oxygen sensors should be replaced every 100,000 miles. In a perfect world that would be it. Wait until a specified mileage and replace the sensor. However, these sensors fail prematurely, set oxygen sensor fault codes and reduce fuel economy. In this article, I will show you how to identify the location of all four oxygen sensors and how to replace them. You will need an oxygen sensor socket to remove the sensors and remember to always work with a cool exhaust. Oxygen sensors are fragile. Do not drop, as damage may occur. Also, keep the sensor tip clean when reinstalling.
Oxygen sensors are laid out in banks, which refer to cylinders and in sensor numbers referring to before or after the catalytic converter. Bank1 or B1 refers to cylinders 1-3. Bank 2 or B2 refers to cylinders 4-6. Sensor 1 or S1 refers to the sensor before the catalytic converter. Sensor 2 or S2 refers to the sensor after the catalytic converter.
Remember that your car may have been serviced before and parts replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have so be prepared with different size sockets and wrenches.
Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Never work on your vehicle if you feel the task is beyond your ability.
Our vehicle may vary slightly from yours as models do change and evolve as they grow older. If something seems different, let us know and share your info to help other users. Do you have questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.
Figure 1 Bank 1 Sensor 1 is indicated by a yellow arrow. Bank 2 Sensor 1 is pointed out with a green arrow. Large Image ' Extra-Large Image
Figure 2 Bank 1 Sensor 2 has a green arrow. Bank 2 Sensor 2 is shown with a yellow arrow. Large Image ' Extra-Large Image
Figure 3 Replacing sensors before catalytic converter: Oxygen sensors are located in the exhaust manifold. Remove the engine covers. See our tech article on engine covers removing. Locate the oxygen sensor electrical connectors at the right side of the engine above the exhaust manifold. Label or mark the wiring harness to aide during reinstallation. I suggest replacing one sensor at a time so you do not mix up connectors. Using an oxygen sensor socket, loosen the oxygen sensor connection to the exhaust manifold. Do not unscrew yet. Large Image ' Extra-Large Image
Figure 4 Replacing sensors before catalytic converter: Pull the wiring harness out of the mounts (green arrows) along the valve cover. Bank 1 sensor 1 shown, bank 2 sensor 1 is similar. Large Image ' Extra-Large Image
Figure 5 Replacing sensors before catalytic converter: Next, disconnect the electrical connector of the oxygen sensor you are replacing (yellow arrow). First, remove the electrical connector from the mounting bracket (green arrow) by pulling straight up. Once out, disconnect the electrical connector by pressing the release tab and pulling it apart. Note the wiring harness color and the factory sensors color code sensors to help when replacing. Locate the color of the sensor you loosened. Using an oxygen sensor socket, remove the oxygen sensor from the exhaust manifold. Lightly coat the new oxygen sensor thread with anti-seize compound. Install the new oxygen sensor and tighten to 50Nm (37 ft-lb). Then reroute the wiring harness and connect the electrical connector. Repeat if replacing both sensors. Then reassemble the engine covers and clear any engine fault codes using a BMW scan tool. Large Image ' Extra-Large Image
Figure 6 Replacing sensors after catalytic converter: Oxygen sensors are located in the exhaust, behind the catalytic converters. Working below the transmission, remove the transmission splash shield. See our tech article on lower splash shield replacing. Using an oxygen sensor socket, remove the oxygen sensor connection to the exhaust manifold. When reinstalling the sensor, do not allow the harness to remain twisted (green arrow). Be sure it is properly routed and tension free. Large Image ' Extra-Large Image
Figure 7 Replacing sensors after catalytic converter: Next, disconnect the electrical connector of the oxygen sensor you are replacing. First, remove the electrical connector from the mounting bracket (green arrow) by pulling it straight out toward the left side of the engine. Once out, disconnect the electrical connector by pressing the release and pulling it apart (inset). Note the wiring harness color, factory sensors color code sensors to help when replacing. Locate the color of the sensor you loosened. Using an oxygen sensor socket, remove the oxygen sensor from the exhaust manifold. Lightly coat the new oxygen sensor thread with anti-seize compound. Install the new oxygen sensor and tighten it to 50Nm (37 ft-lb). Large Image ' Extra-Large Image
Figure 8 Then reroute the wiring harness and connect the electrical connector. Repeat if replacing both sensors. Then reassemble the engine covers and clear any engine fault codes using a BMW scan tool.

Jan 02, 2018 | Cars & Trucks


Which Oxygen Sensor Is It?

There are many inquiries online about which oxygen sensor to change. Oxygen sensor failure codes are very common on a lot of vehicles. With all of today's vehicles having at least two oxygen sensors and many having three or four of them, it can be a little confusing as to which one is causing the problem.

Before we get into which sensor is which, we need to have a little discussion about oxygen sensor fault codes. There are several different types of oxygen sensor fault codes. Here are just some of the most common ones:

P0135 "Oxygen Sensor Heater Circuit Bank1 Sensor 1"
P0141 "Oxygen Sensor Heater Circuit Bank 1 Sensor 2"
P0147 "Oxygen Sensor Circuit Bank 1 Sensor 3"
P0152 "Oxygen Sensor Voltage High Bank 2 Sensor 1"
P0159 "Oxygen Sensor Slow Response Bank 2 Sensor 2"
P0171 "Oxygen Sensor Lean Sensor 1 Bank 1"
P0172 "Oxygen Sensor Lean Sensor 1 Bank 2"
P0174 "Oxygen Sensor Rich Sensor 1 Bank 1"
P0175 "Oxygen Sensor Rich Sensor 1 Bank 2"

There are many more possible oxygen sensor codes, but I only listed these to make my point. Many times the oxygen sensor code is NOT caused by the oxygen sensor itself. "Lean" or "Rich" oxygen sensor codes (i.e. P0171, P0174) are usually caused by something other than the oxygen sensor. Something is wrong, causing the engine to run lean (not enough fuel or too much air) or causing the engine to run rich (too much fuel or not enough air). In these cases, replacing the oxygen sensor will not fix a thing. (That is, unless you are trying to fix your bank account from having too high of a balance!) The new oxygen sensor will just set the same code as the original one. This is because the oxygen sensor is not CAUSING the problem, it is only REPORTING the problem.

High voltage codes (like P0152 above) can be caused by the oxygen sensor wires being shorted to another wire inside the wiring harness. Sometimes these codes are caused by bad grounds where some other component is trying to ground through the oxygen sensor circuit. Again, replacing the oxygen sensor will not fix this! In short, the problem needs to be diagnosed before running out and buying an oxygen sensor.

Just because a fault code has "Oxygen Sensor" or "O2 Sensor" or "O2S" in its description does not necessarily mean that an oxygen sensor needs to be replaced. Many do-it-yourselfers believe that all there is to fixing the car is to hook it to the "magic box", collect the fault codes and replace the parts the computer tells you to replace. There is nothing further from the truth.

Fault codes only point you toward which SYSTEM is failing. The system must be diagnosed to find the CAUSE of the failure. If this is not done properly, it will only result in wasting a bunch of your money. This is what you were trying to avoid by doing it yourself!

So, after reading all of the above, if you think you still want to replace an oxygen sensor, but don't know which one; here is how to figure it out:

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 #1 is located and, of course, Bank 2 is the opposite side.
On a 4 cylinder engine, there is only one bank and it is always referred to as Bank 1. The exception to the 4 cylinder rule is on certain 4 cylinder engines (specifically, some Toyotas) there are two catalytic converters used. In this case, Bank 1 sensors will still be in the pipe for the catalyst that is connected to cylinder #1 and Bank 2 sensors will be in the other one.

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).
Sensor 3 refers to the ONLY "downstream" sensor where there are two sensors before the catalyst and only one after the catalyst. On very few vehicles the reference to this reads "Bank 1 Sensor 3".

If you do not know where cylinder #1 is, then you need to get a diagram of the firing order for your engine. Just post a question on and make sure you give the YEAR, MAKE, MODEL, and ENGINE SIZE of your vehicle and one or more of our experts will be happy to tell you how to find cylinder #1.

ASE Certified Master Automobile Technician

Also check out this article by dttech: What Else Could Be Wrong?

on Apr 29, 2011 | Ford F-150 Cars & Trucks

1 Answer

Rx300 lexus , getting check engine light and vsc indicators on. autozone ran codes po441,po442,po446,po420.all are evap emissions sys except po420- catalyst sys. efficiency below threshold (bank 1).

bank 1 is driver side cat sensor. if one sensor goes it can get false readings on others. it could just be a seal on one of the connectors, but to find the faulty sensor is seals are fine. you need to find out the resistance on the sencore the live the negative and the signal wire are and use a meter with the engine running connect the meter to the wires with paper clips in the back of the plug with it connected it needs to be on the signal and the negative, the resistance should go up and down in resistance with engine output rev engine slowly if it moves smooth then its fine, if its not then its that sensor at fault. you can do this if you have a code reader and remove sensors one at a time till you only get one code left then the one you removed is the sensor at fault.

Jun 14, 2017 | Lexus Cars & Trucks

1 Answer

Codes po420 and po 442 keep popping up on my 2005 Cadillac deville it has 90,000 miles what would be the most serious issue do you think all the most likely issue wrong with my car

Failed Ignition Coils

Resulting cylinder misfires over time
have ruined the exhaust converters (PO420 Bank #1)

PO442-small leak in Evap System

It's all on the internet ,if you Google your codes
& study OBD2 Systems

Type: OBD PO 442

On a 2005 vehicle-- All-- the ignition coils will be bad after
7 or 8 years

At 100,000 miles the front Oxygen Sensors need to be replaced

Jul 14, 2014 | Cars & Trucks

1 Answer

How do I replace an oxygen sensor (code 21) in a 1993 Toyota Camry?

you need oxygen socket and 3/8 ratchet wrench.easy way to replace oxygen sensor is to start vechicle let run few minutes just enough to get exhaust system hot so it will make it easier remove oxygen sensor.just remove heat shields disconnect oxygen sensor electrical connector then replace oxygen sensor.use penetrating oil let it soak around oxygen sensor for 20 minutes that will help make it easier to remove sensor.

Sep 16, 2013 | Toyota 4Runner Cars & Trucks

1 Answer

Just went to autozone to see what could be wrong with my car. So far, I see the gas cap was not placed on properly after pumping and the gas was probably topped off. Got these codes. p0420, p0441, p0446

PO420- Catalyst System Efficiency Below Threshold (Bank 1) More than likely a plugged converter or exhaust.Remove the upstream O2 (it'll set a code and be real loud) and then take it for a spin and see if power is restored.
vacuum switching valve may fix the PO441 code. Replacing the charcoal canister could be another thing also. Then your PO446 is EVAP emission control system incorrect purge flow. which could a gas cap, could be a fuel pump seal or pressure sensor, filler neck.

Aug 30, 2013 | Toyota Camry Cars & Trucks

1 Answer

2003 toyota matrix with code po420

You don't check O2 Sensors when cold,
they won't be operating or switching until
the computer goes into closed loop & converter
lights off at 600 degrees & continues to hopefully
around 900 to 1,100 degrees
Other than replacing a sensor, the only real
test I found of any value, is to watch switching
times on an oscilloscope
You can, as you said, look at scan tool data
Giving your vehicle is a 2003 & converters last
12 to 14 years, you know yours is worn out,doesn't
matter what the inspection gas results were & with
any codes, you should have been rejected & not tested
If you check fuel trim,you will see how well the MAF Sensor
is doing & you can't adjust fuel if the converter is not capable
of holding oxygen for the sensors to read
The front O2's get replaced on all vehicles at 100,000
when or before they slow down & fail

Jul 09, 2013 | Cars & Trucks

1 Answer

Code 21,43,and 42

You have two oxygen sensors but 21 is upstream sensor. This is the sensor between engine and catalytic converter. There is three possible problems that it could be.
1 oxygen sensor input voltage maintained above the normal operating range.
2 no signal at 02 2/1 sensor
3 oxygen sensor input voltage sustained above thenormal operating range. What all this means is you need to replace the sensor.
when getting the replacement this is your O2 2/1 sensor.

May 13, 2013 | 1996 Jeep Cherokee Country

1 Answer

My 02 camry le failed emmission test whats wrong error codes po440, po441, po446, po420

You have codes for a failed exhaust converter,PO420,
EVAP System problem PO440,Incorrect Purge Flow PO441,
Evap Vent Control issues,PO446

Your car is all messed up

That should have been all checked, BEFORE you spent time
in line for inspection

If all the codes are for real & not a false report

You will need new spark plugs,ignition & fuel checked,
new exhaust converters,new evap purge valve,new evap
vent solenoid & possibly vacuum leaks resolved

You either bought someones neglected vehicle or never
do a thing but drive it

May be easier to get a different vehicle,your repair bill
will start at $1,000 & go up, from not being proactive & taking
care of what is required in owning any vehicle (lack of knowledge)

You will need the oxygen sensors also & no, they won't fix the
amount, of what appears to be several failed items, all at one time

So much for Toyota being better than other vehicles

Apr 03, 2013 | 2002 Toyota Camry

2 Answers

I am a female trying to save some money, I would like to know if the 02 sensor something that I can replace

Depends on how strong you are because these sensors are in the exhuast manifold and they are uasally rusted.You have to be careful not to cross thread them when you reinstall.

Apr 09, 2011 | Mitsubishi Diamante Cars & Trucks

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