Toyota Yaris 2008 1.0

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Toyota Yaris 2008 1.0

Postby Peter704070 » Fri Nov 29, 2013 5:05 pm

Hello we had a Yaris in our college workshop today, the students fitted our Delphi DS150e and it came up with code P0138, this related to Lambda Sensor after the catalytic converter. They tried to look at live data but it won't show the pre cat lambda sensor.

We then got the scope out and tried scoping the pre cat sensor - it has four wires, two black a blue and white. We tried the ble wire and got a voltage of 3.0 volts which didn't change as the vehicle revs increased. We then tried the white wire and got the same result.

To check the sensor we then got a multimeter out and checked both black wires and got 4 ohms resistance. Does anyone know how these sensor operate - we thought the sensor would be the Zirconia type, is this right or have we got something wrong and how should we test the sensor.

Thanks
Pete
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Re: Toyota Yaris 2008 1.0

Postby KimAndersen » Fri Nov 29, 2013 7:13 pm

Hi there

Maybe i can help you if you will provide me with the correct engine code. The wire color from your oxygen sensor does not match the wiring diagram i have.

Regards
Kim
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Re: Toyota Yaris 2008 1.0

Postby arjen » Fri Nov 29, 2013 8:52 pm

I think you have a denso wide band sensor.
Toyota uses a lot of these 4 wire wide band oxygen sensors. Most scantools can show the value that is measured by the sensor. When the sensor says its running at lambda 1 you can confirm this with a gas analyzer.
The ecu is tries to keep the voltage over the sensor as constant as possible so there is no signal to see in the voltage.
If you want to measure the sensor with a scope hou have to use a milli ampprobe and measure the current on the signal wires.
If you Google on denso 4 wire wide band you can find more info.
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Re: Toyota Yaris 2008 1.0

Postby Avdr » Sat Nov 30, 2013 10:28 am

You start by saying correctly that P0138 relates to the post CAT lambda, then we jump to the pre CAT lambda.

I've no experience of the 4 wire denso wideband, it could well be the case - only you can confirm that with a part number. I would be suprised if the post CAT is also wideband though.
Have you just got sidetracked from looking at the rear when you discovered your scan tool doesn't show live data for the front sensor?
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Re: Toyota Yaris 2008 1.0

Postby Peter704070 » Sat Nov 30, 2013 10:42 am

Morning

I should have said we started looking at the at at 3:00 yesterday with a group of Level 3 students - we only had 30 minutes before the lesson finished. The car is a students from anothe department and apparently they had been to a garage and replaced the post cat sensor.

We didn't have a free ramp on Friday so the students just wanted to get some results - we've been talking about lambda sensors over the last few session. We expected to see the normal 0.1 - 0.9 fluctuation but all we got was a straight 3.5 volts.

They couldn't get to the post cat Lambda sensor and that's why we jumped to the pre cat one. I will get an engine code on Monday and post the results.

Thanks
Pete
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Re: Toyota Yaris 2008 1.0

Postby KimAndersen » Sun Dec 01, 2013 2:19 pm

Hi Pete

I must admit i had to read your post a couple of times before i could see the context between the two sensor you are talking about.

I've got some extra information regarding the DTC P0138 which according toyota is related to heated oxygen sensor (Bank 2) - post catalytic converter sensor.

DTC_P0138.jpg
Yaris 1KRFE DTC P0138


As far as the information I´ve giving you here are taken from a Yaris with the engine code (1KR-FE) from around approx. 2008 and these engines is fitted with zirconia oxygen sensors on both pre and post the catalyte converter.

So what´s installed on your Yaris depends on what engine code it has.

It looks that you got two problems - one with the pre oxygen sensor and a another with the post oxygen sensor or maybe its a combined problem !.

Regards
Kim :wink:
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