Code PO155, Oxygen sensor location needed

Tiny
DEQUESO
  • MEMBER
  • 2003 CHEVROLET ASTRO
  • 4.3L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 78,000 MILES
Scanner read out PO155 02 heater circuit (bank 2, sensor 1). Can you let me know where that is located and is there only 1? 1 bad rest good?
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Friday, July 2nd, 2021 AT 12:31 PM

11 Replies

Tiny
ASEMASTER6371
  • EXPERT
Hello again.

The sensor is on the passenger side of the motor just down from the exhaust manifold. It is before the cat converter.

https://www.2carpros.com/articles/how-an-oxygen-sensor-works

https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor

I attached the flow chart for the code. Most of the time, it is the sensor that is bad but you need to verify it by following the flow chart.

Roy
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Friday, July 2nd, 2021 AT 2:15 PM
Tiny
DEQUESO
  • MEMBER
Can I remove the sensor drive to buy new sensor to compare that it is the same long trip to parts store? Also what kind of scanner do I need to check flow? I am a novice to the new cars. Great info great web.
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Saturday, July 3rd, 2021 AT 5:29 AM
Tiny
ASEMASTER6371
  • EXPERT
Yes, you could but not recommended. You could loosen it and make it easy to remove when you get to the parts store.

There is only one sensor for sensor 2 bank 1. Do not get a universal sensor. They are not qualified and may not even work out of the box. Get a name-brand sensor.

Roy
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Saturday, July 3rd, 2021 AT 6:16 AM
Tiny
DEQUESO
  • MEMBER
Good idea good info again. It will be a while before I get 2 it. Thank you and have a good 4th. One little thing AutoZone gave me a bosch #15898 exact fit. That should be the right one not universal?
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Saturday, July 3rd, 2021 AT 8:19 AM
Tiny
ASEMASTER6371
  • EXPERT
That is correct.

You are welcome.

Always glad to help.
.
Roy
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Saturday, July 3rd, 2021 AT 9:54 AM
Tiny
DEQUESO
  • MEMBER
Prior to replacing oxygen sensor 02 disconnected battery put jumper from positive 2 negative set 10 minutes replaced sensor. Does the check engine light stay on if so about how long?
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Tuesday, July 13th, 2021 AT 8:12 AM
Tiny
ASEMASTER6371
  • EXPERT
Why are you doing that? That does absolutely nothing at all.

Roy
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Tuesday, July 13th, 2021 AT 1:59 PM
Tiny
DEQUESO
  • MEMBER
Thought that was the way to get check engine light off after replacing bank 2 sensor.
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Tuesday, July 13th, 2021 AT 2:13 PM
Tiny
ASEMASTER6371
  • EXPERT
No. I do not know who told you that but it is not the way.

You could remove the negative battery cable for about 10 seconds or you can use a scan tool to clear the code.

Roy
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Tuesday, July 13th, 2021 AT 2:40 PM
Tiny
DEQUESO
  • MEMBER
I will give that a try. Thank you
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Tuesday, July 13th, 2021 AT 2:45 PM
Tiny
ASEMASTER6371
  • EXPERT
You are welcome.

Always glad to help.

Roy
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Tuesday, July 13th, 2021 AT 2:51 PM

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