O2 sensor again

[BOSMECH]

Well I just replaced my O2 sensors (all 4) in July and now I just got the code bank 2 sensor 2 which is drivers side after the CAT which is easy to change but it sucks that I just did them.
Has anyone else had this problem also they were Denso and have reset them with my OBD II scanner 3 times and comes back the same. I checked the wire harness also and it is good next will be to Ohm out the sensor to be sure, but the scan tool is pretty acurate.

 

[Jyn]

Have you checked your catalytic converter? The plugs could be getting polluted and dirtied with foul air that isn't being cleaned.

 

[BOSMECH]

No I have not.
How do you check them.

 

[cabowally]

How to check your vehicle's catalytic converter. - YouTube





.

 

[BOSMECH]

Well I am not drilling holes in my system and the forward sensor would pick it up and give me a fault.
I think I just got a bad O2 sensor for some reason.
And to top it off my inspection sticker is due by the end of the month.
No big deal I will erase the fault get the inspection then replace the sensor.

 

[stevec5000]

Well I am not drilling holes in my system and the forward sensor would pick it up and give me a fault.
I think I just got a bad O2 sensor for some reason.
And to top it off my inspection sticker is due by the end of the month.
No big deal I will erase the fault get the inspection then replace the sensor.

Ha ha, scottykilmer is a moron. Don't drill holes in your cat unless you are too lazy to take it off and have a look in it. You should be able to see clearly through the ceramic matrix inside. It should look clean and not have any cracks, breaks or clogged spots.
You shouldn't replace the O2 sensors before checking them to make sure they are actually bad either. They should last several years unless something terrible happens to damage them. There are other problems that can cause the codes to be displayed so I wouldn't replace one before checking it. Could just be a blown fuse or bad connection feeding power to their internal heater.

 

[BlackWorksInc]

Ha ha, scottykilmer is a moron. Don't drill holes in your cat unless you are too lazy to take it off and have a look in it. You should be able to see clearly through the ceramic matrix inside. It should look clean and not have any cracks, breaks or clogged spots.
You shouldn't replace the O2 sensors before checking them to make sure they are actually bad either. They should last several years unless something terrible happens to damage them. There are other problems that can cause the codes to be displayed so I wouldn't replace one before checking it. Could just be a blown fuse or bad connection feeding power to their internal heater.

Actually he's both right and wrong in his way of testing a catalytic converter, without going too much into detail about it (don't have the energy to type it out tonight lol.) The only true comprehensive test on a catalytic converter is an invasive test (drill a hole) and use a 4 or 5 gas analyzer to watch whether or not the catalytic converter is actually doing its job chemically/thermally.

You can have a cat that breathes properly but no longer is able to maintain a proper catalytic reaction. Another thing to note is that OEM and most non-invasive testing of the catalytic converter only tests its ability to store O2 as a test of its "catalytic efficiency" which doesn't account for the other processes that occur inside of the unit.

As for the OP, you can check the resistance though I don't remember what the spec is for the heater and O2 Sensor itself. If you happen to have a DSO (digital storage osciliscope) I would back probe into the O2 sensor wiring and see how fast the unit is switching. You should be seeing it switching from roughly 0~.1v to .8~1v in under 100miliseconds after snapping the throttle, that will give you an indication of the sensor's health.

 

[450exc115]

Sounds like the catalytic converts are bad. What year and how many miles are on the 4runner?

Another test would be to spend money on a wide band o2 sensor and gauge and use that to see if the catalytic is working. The cost of the tool is a lot but it's a good tool to have in the tool box for any diagnotic work on how a car is running.

Testing the sensor is a good idea too, most sensors fail only because the heater fails, and the heater is what is needed to ensure the measurement is acurate (the sensor only work in a specific temperature range).

 

[cabowally]

FSM:

Powertrain Management » Computers and Control Systems » Oxygen Sensor » Testing and Inspection » Heated Oxygen Sensor

2UZ-FE EMISSION CONTROL: HEATED OXYGEN SENSOR: INSPECTION

INSPECT HEATED OXYGEN SENSOR (for Sensor 2)

(a) Using an ohmmeter, measure resistance between the terminals.

(FSM has a diagram of the terminals and what the resistance should be)






.

 

[stevec5000]

The only true comprehensive test on a catalytic converter is an invasive test (drill a hole) and use a 4 or 5 gas analyzer to watch whether or not the catalytic converter is actually doing its job chemically/thermally.

Not true, you can just look to see if you can see through it and don't need to drill any holes to tell if it flows OK and check it's operation by checking the rear O2 sensor against the front one. The front one should read normal mixture while the rear one should read a lot lower.

 

[stevec5000]

Another test would be to spend money on a wide band o2 sensor and gauge and use that to see if the catalytic is working. The cost of the tool is a lot but it's a good tool to have in the tool box for any diagnotic work on how a car is running.

Again, not true. An expensive tool isn't needed because the output of an O2 sensor can be checked with a normal DVM to see if the reading is around 0.5 volt. You can also use an O2 gauge or ScanGauge.

Testing the sensor is a good idea too, most sensors fail only because the heater fails, and the heater is what is needed to ensure the measurement is acurate (the sensor only work in a specific temperature range).

I've never seen one fail because the heater was bad but I've seen several fail when the sensor went bad.

 

[BOSMECH]

Well I checked it with my OBDII scanner while it was running and yep its the O2 Sensor and Ohm it out and it is bad.
So with only 4 months on it I am going to mail it bck to Denso and Hope to get a new one to replace it.

 

[450exc115]

Again, not true. An expensive tool isn't needed because the output of an O2 sensor can be checked with a normal DVM to see if the reading is around 0.5 volt. You can also use an O2 gauge or ScanGauge.

Umm I was saying using a wide band to check the cat not the sensor.

Now did he buy and aftermarket sensor or toyota sensor?

 

[BlackWorksInc]

Not true, you can just look to see if you can see through it and don't need to drill any holes to tell if it flows OK and check it's operation by checking the rear O2 sensor against the front one. The front one should read normal mixture while the rear one should read a lot lower.

Like I said, I'm trying to keep it simple. You're right though, your method is how all manufactuers test their catalytic converters on the vehicle. But this test is only a measure of the cat's ability to store oxygen. There are 4 other gases involved in the chemical reaction that are not actively measured by the computer, they are inferred by the cat's ability to store oxygen which is mostly accurate, but not a definitive test of its actual functionality.

There are lot of great articles on catalytic converter operation and diagnosis that go into great detail. I've also gone into some detail in some older threads (I'll dig up the link when I have the time.) I just like to be rather through in my testing. :nerd:

 

[BOSMECH]

I installed all Denso and am going to use Denso again, It was the drivers side after cat sensor (Bank 2 Sensor 2).
I also just fail my saftey inspection for no memory in the computer, which I cleared before going since I have not changed the sensor yet so I will have to change it then go again.
Also he failed ny seat bellt latch that got broken when I believe he tried putting the middle buck in the passenger side latch on the back seats.
If you look at a 2003 seat belts in the back the middle one has a diffrent buckle from the other 2 and it will only go in the middle latch and if you try putting it in the others it will phuck them up.

 

[MikeInNH]

Stick with Denso or NGK sensor. Denso and NGK make Toyota's O2 sensors anyways. If you buy a toyota sensor it's just a rebadged Denso or NGK.

As for the catalytic converter. The way the vehicle's OBDII system tells if you have a bad cat is by the O2 sensor. There are tests to determine which actually is bad...usually it's testing the O2 sensor.

Product & HowTo Info | | | TEST | AutoZone.com

If the O2 sensor passes..then the problem is usually the catalytic converter.

 

[BOSMECH]

Also the codes are what point to the CAT or the sensor i told him my code and he said the it's the sensor.
But most importnaly was the actual valves while the engine was running and the B2S2 sensor was way out of whack. so it is a no brainer.
But as for the seat belt buckle and now the greasy hand print on my seat that I just found pisses me off more then the sensor it self.

 

[BOSMECH]

Well per Alldata you are suppose to do these checks on the O2 sensor and if passes that part you do more checks and then replace the sensor but there is also a part were you Ohm out the sensor and its bad then of course replace but if it Ohms good then you check the wiring and ECM and if it passes you then again are told to replace the sensor.
So the bottom line is just replace the sensor which I did and then to in for inspection and she passed.
Now I am sending the 4 month old one back to Denso and hope they replace it.

 

[noshacal]

Also pulled a bank2 sensor2 code on my 4runner today. Tired of pulling the P136 code, went to carquest and the guy went out to his car and used his personal obdII meter and found fluctuating voltage overall but then no voltage from the 2/2 sensor. 4 years of code problems and I get a solid lead. New battery, newish sensors, constant pain. EVERYONE wants to throw sensors at you. If I can't find the bad wire I will just reset it 1 week before annual inspection and live with it. 204K miles.