OBD2 doesn't see oxygen sensor

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Old 12 Oct 2004, 09:08 pm   #1 (permalink)
Andrew
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Default OBD2 doesn't see oxygen sensor

Hi.
I suspected, that my Toyota Echo 2000 runs lean.
I tested oxygen sensor and was getting readings 0.2V which is lean
mixture.
But I was very surprised, because I didn't get "check engine" light
when I was doing that. I thought it would come on emmideately sinse I
disconnected sensor??? It was disconnected for 10 min. I even ran for
5 min with it disconnected. So, now I know that sensor is ok, byt OBD2
doesn't receive the signal and doesn't corect mixture. What is the
problem??? Do I need to go to diller and check the computer??? Any
help, please...
Thanks.
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Old 12 Oct 2004, 10:48 pm   #2 (permalink)
Philip
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Default Re: OBD2 doesn't see oxygen sensor

Andrew wrote:
> Hi.
> I suspected, that my Toyota Echo 2000 runs lean.
> I tested oxygen sensor and was getting readings 0.2V which is lean
> mixture.
> But I was very surprised, because I didn't get "check engine" light
> when I was doing that. I thought it would come on emmideately sinse I
> disconnected sensor??? It was disconnected for 10 min. I even ran for
> 5 min with it disconnected. So, now I know that sensor is ok, byt OBD2
> doesn't receive the signal and doesn't corect mixture. What is the
> problem??? Do I need to go to diller and check the computer??? Any
> help, please...
> Thanks.



The only proper way to check the O2 sensor (and the air/fuel mixture sensor
if equipped with both) is to use an OBDII interface device. What you did is
NOT the correct method and therefor, your findings invalid.

--

-Philip


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Old 13 Oct 2004, 09:02 am   #3 (permalink)
Andrew
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Default Re: OBD2 doesn't see oxygen sensor

"Philip" <1chip-state1@earthlink.net> wrote in message news:<3A1bd.2739$gy1.972@newsread1.news.pas.earthl ink.net>...
> Andrew wrote:
> > Hi.
> > I suspected, that my Toyota Echo 2000 runs lean.
> > I tested oxygen sensor and was getting readings 0.2V which is lean
> > mixture.
> > But I was very surprised, because I didn't get "check engine" light
> > when I was doing that. I thought it would come on emmideately sinse I
> > disconnected sensor??? It was disconnected for 10 min. I even ran for
> > 5 min with it disconnected. So, now I know that sensor is ok, byt OBD2
> > doesn't receive the signal and doesn't corect mixture. What is the
> > problem??? Do I need to go to diller and check the computer??? Any
> > help, please...
> > Thanks.

>
>
> The only proper way to check the O2 sensor (and the air/fuel mixture sensor
> if equipped with both) is to use an OBDII interface device. What you did is
> NOT the correct method and therefor, your findings invalid.



OK....
BUT WHY I DIDN'T GET CHECK ENGINE LIGHT ON???
THIS IS MY MAIN QUESTION....
THANKS
ANDREW
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Old 13 Oct 2004, 09:39 am   #4 (permalink)
ROBMURR
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Default Re: OBD2 doesn't see oxygen sensor

Your original problem:
I own Toyota Echo 2000 (100k)
Recently it started to vibrate more then usualy.
I replacet all spark plugs, tested all sensors.
Everything seems to be ok.
I suspect oxygen sensor.
I think mix is too lean and sensor can't sense it.

Your looking in the wrong place, forget the O2 sensor.
When is it vibrating? At idle, full throttle or driving down the road?
Is it driveable?
Have you looked at Alldata for any related TSB's?
How are the motor mounts?
Have you had the injectors cleaned?(not that pour in the tank crap)
When did you replace the fuel filter?
Have you tested the sparkplug wires?
Have any vaccum hoses fallen off?
What brand plugs were in it and what
brand did you replace them with?
If you have done all this, forget it and take
to the dealer, it will cost less in the long run.

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Old 13 Oct 2004, 12:22 pm   #5 (permalink)
Philip
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Default Re: OBD2 doesn't see oxygen sensor

Andrew wrote:
> "Philip" <1chip-state1@earthlink.net> wrote in message
> news:<3A1bd.2739$gy1.972@newsread1.news.pas.earthl ink.net>...
>> Andrew wrote:
>>> Hi.
>>> I suspected, that my Toyota Echo 2000 runs lean.
>>> I tested oxygen sensor and was getting readings 0.2V which is lean
>>> mixture.
>>> But I was very surprised, because I didn't get "check engine" light
>>> when I was doing that. I thought it would come on emmideately sinse
>>> I
>>> disconnected sensor??? It was disconnected for 10 min. I even ran
>>> for 5 min with it disconnected. So, now I know that sensor is ok,
>>> byt OBD2
>>> doesn't receive the signal and doesn't corect mixture. What is the
>>> problem??? Do I need to go to diller and check the computer??? Any
>>> help, please...
>>> Thanks.

>>
>>
>> The only proper way to check the O2 sensor (and the air/fuel mixture
>> sensor
>> if equipped with both) is to use an OBDII interface device. What
>> you did is
>> NOT the correct method and therefor, your findings invalid.

>
>
> OK....
> BUT WHY I DIDN'T GET CHECK ENGINE LIGHT ON???
> THIS IS MY MAIN QUESTION....
> THANKS
> ANDREW


Because the sensor is NOT defective. You test procedure is defective.

-Philip


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Old 13 Oct 2004, 07:37 pm   #6 (permalink)
kiselink@mindspring.com
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Default Re: OBD2 doesn't see oxygen sensor

Per 1995 Camry Service manual for 1MZ-FE (V6):
- disconnect the O2 sensor connector.
-Using an Ohm meter measure between terminals +B and HT.
-If resistance is not between 11 and 16 ohm at 68 degrees fahrenheit,
replace the sensor.

When viewed looking into the connector - the top has three notches and
the bottom has 2 notches. Upper left is +B and upper right is HT.




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Old 14 Oct 2004, 01:07 am   #7 (permalink)
Philip
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Default Re: OBD2 doesn't see oxygen sensor

kiselink@mindspring.com wrote:
> Per 1995 Camry Service manual for 1MZ-FE (V6):
> - disconnect the O2 sensor connector.
> -Using an Ohm meter measure between terminals +B and HT.
> -If resistance is not between 11 and 16 ohm at 68 degrees fahrenheit,
> replace the sensor.
>
> When viewed looking into the connector - the top has three notches and
> the bottom has 2 notches. Upper left is +B and upper right is HT.



The only valid O2 sensor test is the dynamic response test performed by the
car's onboard computer. Checking the O2 sensor's heating element is not a
complete test.
--

-Philip


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