Any easy way to check a O2 sensor??

[Slocrow]

Just wondering if there is a easy way (no expensive meters) to check whether a O2 sensor is functioning correctly, or not? My 99 V6 Camry is throwing a PO135 code which is the heated upstream O2 sensor (Bank 1, Sensor 1). Replacement cost at the dealer retail is $162 and even internet RockAuto is at $75. I'd like some easy way to confirm that it's the problem and bad.
Is there only that one upstream in the exhaust header? I can't believe it's location. If I'm correct, Bank 1 is the driver side and even with the FWD I believe it's right there behind the radiator, in the exhaust header. Right in plain sight with no apparent get to problems. From the horror stories I've heard I just couldn't believe the easy location. I even looked for a second against the fire wall, assuming that's where I had to go.
Now if I just was sure it was the sensor that was bad. ...................
Thanks, Frank

[ajkalian]

Originally Posted by Slocrow

Just wondering if there is a easy way (no expensive meters) to check whether a O2 sensor is functioning correctly, or not? My 99 V6 Camry is throwing a PO135 code which is the heated upstream O2 sensor (Bank 1, Sensor 1). Replacement cost at the dealer retail is $162 and even internet RockAuto is at $75. I'd like some easy way to confirm that it's the problem and bad.
Is there only that one upstream in the exhaust header? I can't believe it's location. If I'm correct, Bank 1 is the driver side and even with the FWD I believe it's right there behind the radiator, in the exhaust header. Right in plain sight with no apparent get to problems. From the horror stories I've heard I just couldn't believe the easy location. I even looked for a second against the fire wall, assuming that's where I had to go.
Now if I just was sure it was the sensor that was bad. ...................
Thanks, Frank

Sorry you are mistaken. Bank 1 in a V6 is the one closest to the firewall. Bank 1 is always were Cylinder 1 is. Bank 2 is the one closest to the radiator.

Here's something that will clear it all up.

http://www.toyotapart.com/Engine_Ban...SB-0398-09.pdf


Or you can search for Toyota Technical Service Bulletin (T-SB-0398-09) should the above link be in violation of TN's posting rules.


I just don't want to be hit with Lynchburg's BanHammer



.

[Slocrow]

Okay, I stand corrected and thank you for the direction. So does that mean that I've got two O2 sensors upstream or just the one, apparently hidden back by the firewall? If only the one near the firewall in Bank 1, what is that sensor in the exhaust header of Bank 2, near the radiator? .Frank

[Slocrow]

ajkalian; Thanks for the TSB. I didn't notice how complete it was when I jumped to answer. I'll have to review it closer. At first glance it look's like I've got about 4 O2 sensors. Do you agree? Frank

[fenixus]

I believe you have 3 oxygen sensors. if your car meets california emission specs than both upstream (front & rear) are Air Fuel Ratio sensors (much more expensive) and for federal emission specs (I guess this is yours based on dealer price) regular narrow band thimble type oxygen sensors are used.

the last sensor is downstream or post-catalytic (located after catalytic converter) and is used only to monitor cat converter efficiency while both upstream ones are crucial for the ECU to set correct fuel trims.

[fenixus]

http://www.densoaftermarket.com/cata....php?part=o2sn

federal specs, upstream o2 sensor for '99 V6 is Denso p/n 234-4622 (same part for both front & rear bank), around $90 new original OEM on ebay, e.g.:

http://cgi.ebay.com/ebaymotors/DENSO...Q5fAccessories

I've seen at least one seller on Amazon selling those at like $63+s/h, look for Denso manufacturer, some sell some el cheapo equivalents made by different companies.
other acceptable manufactures would be NGK/NTK but they are seriously overpriced (only a little cheaper than OEM from dealers).

stay away from Bosch, that brand really doesn't serve well in Toyotas, everything I had with Bosch logo on it (including my ABS pump on 1mz-fe) was a total crap.

you can test your old sensor with a multimeter. you would need to measure resistance of 2 pins in the sensor's plug. the norm reading range at 20C/68F is 11-16ohm while at 800C/1,472F it produces 23-32ohm.

[Mister_Perkins]

Dont buy any O2 sensors that you Wire together. They are cheap and dont work. I've seen a lot of people do this, and its a waste of money. Always get a Direct Fit Replacement O2 sensor

[ajkalian]

Originally Posted by Slocrow

ajkalian; Thanks for the TSB. I didn't notice how complete it was when I jumped to answer. I'll have to review it closer. At first glance it look's like I've got about 4 O2 sensors. Do you agree? Frank

Nope, you probably don't have 4 sensors. It depends on what model you have. If you have a federal spec car you might have only two of them. If you have a Calif spec car you probably have three. Only one will be an o2 sensor, and it would be located after the cat. The other two are technically not o2 sensors, rather Air/Fuel sensors. Much more expensive that regular o2 sensors.

The diagram number 8 is confusing in two ways. First the way it is labeled. It says #1 is Bank 2 Sensor 1. They could have just as easily said that #1 was Bank 1 Sensor 1, but noooo. Additionally I don't think there is a model that has the 4th sensor, Bank 2 Sensor 2. But if you did have one there that's what it would be labeled.

So not to pic nits, you have 2 A/F sensors located on each of the exhaust manifolds, and maybe one o2 sensor, located after the cat for a total of 3. But I doubt you have 4.

Maybe somebody could chime in as to what models have all 4 sensors.


There, I'm sure that clears everything up.


.

[LynchburgCSI]

Originally Posted by ajkalian

Sorry you are mistaken. Bank 1 in a V6 is the one closest to the firewall. Bank 1 is always were Cylinder 1 is. Bank 2 is the one closest to the radiator.

Here's something that will clear it all up.

http://www.toyotapart.com/Engine_Ban...SB-0398-09.pdf


Or you can search for Toyota Technical Service Bulletin (T-SB-0398-09) should the above link be in violation of TN's posting rules.


I just don't want to be hit with Lynchburg's BanHammer



.

TSB's are okay. (I actually have that one saved on my hard drive.) FSM direct links are NOT.

[google123]

Amazon has better prices on a lot of parts if you have the correct part numbers.....

Also, when researching parts I like to find part numbers using websites such as RockAuto and then do a web search for better prices. I just recently purchased Denso Oxgen sensors that I got the part number to from RockAuto but purchased from Amazon for like $45 each as opposed to RockAuto's $60-$75 prices. I use this for other things as well. I use Crutchfield to research stereo equipment and then buy elsewheres.

[Kiwi-Corolla]

Originally Posted by Slocrow

Just wondering if there is a easy way (no expensive meters) to check whether a O2 sensor is functioning correctly, or not?

You should be able to check the voltage of the oxygen sensor by back-probing the signal wire of the connector with a digital multimeter. I'm not sure what the specified voltage should be for your Camry, but if it's anything like my Corolla then it should be between 0.1-0.9 volts when the engine is the normal operating temperature.

With the engine at normal operating temperate, rev the engine to 4000rpm and the voltage should fluctuate between 0.1-0.9 volts (it'll be about 0.3 volts at idle). If the multimeter reading doesn't rise above 0.7 volts, a lean mixture is indicated. If the multimeter reading doesn't fall below 0.35 volts, a rich mixture is indicated. If the multimeter reading shows 0 volts however, then replace the oxygen sensor.

Please bear in mind that the voltage specifications I listed are in reference to my Corolla, so it would pay to check a factory service manual to see what the specifications are for your Camry. Either way, it's worth testing with a digital multimeter, even if you just write the voltages down and call an auto electrician to get their opinion. Alternatively, just replace the sensor and hope for the best . Good luck!

[SexieWASD]

A quick google search (I don't have my obdII code memorized) shows that code P0135 is an O2 sensor heater circuit malfunction, The advice given so far is to test the sensor circuit. Four wire O2 and A/F sensors have two differant circuits that are not directly connected inside of the sensor. The second circuit is the heater circuit and is indicated by matching wire colors coming out of the back of the sensor, this circuit works just like a little toaster, it's a resistive coil of wire that gets hot when voltage is applied to it. It heats up the O2 sensor when it is cold so that the O2 sensor will quickly get to operating temperature as they are not accurate when cold. You can test it easily with a DMM by setting it to measure resistance and connecting it to both wires of matching color (usually both white or gray) the polarity does not matter, the resistance should be around 1ohm, not quite a short, but close to it, if it measures infinite or very high resistance then the heater coil has burned itself. You can then check that one of the matching wires is being supplied with voltage, and the other has a ground connection. Remember that the car will switch off the heater (usually by cutting the ground path) after about a minute, so you may have to test quickly for power and ground after turning the key to the On position, but without starting the engine (for safety).

I hope that this giant wall of text has helped someone.

[AliRazoR]

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