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Oxygen sensors up Stream down Stream?

Tiny
ALPHASENTORY GALAXY
  • MEMBER
  • 2009 PONTIAC VIBE
  • 1.8L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 80,000 MILES
Hello good fellows,

The vehicle listed above has a voltage reading of 3.89 volts it is high on the up stream o2 sensor and the down stream reads 0.0 when it is in close loop when it should read 07.80 mili volts.

when tapping the down stream sensor it comes back to normal readings 780 mm volts.

When performing ohms teat on up stream o2 sensor it reads 1289 ohms. This too indicates a high resistance. Checked the 4 wire sensors powers and grounds good however when checking ground and signal wire it read 1289 ohms is the up stream compensating for the down stream? Is this normal?

The fuel trims seem strange short term fuel trims and long term fluctuating between -5 to oo to + 5 and higher on short term; the long term stays above +10. I still have not learned how to interpret these cycles with the o2 sensors and mass air flow sensor?

Baffled by these complex air ratios to fuel and a healthy o2 sensor?

Respectfully,
Alphasentory galaxzy
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Tuesday, November 30th, 2021 AT 10:57 PM

12 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Thanks for the kind words.

Sounds like the upstream sensor has failed and even the downstream seems odd.

Here is a guide that will help with this testing just to make sure we are testing it correctly. You should be checking the voltage on pin 3 and ground. Then pin 4 and ground. These are your signal wires, so we need to see what they are doing. However, we need to make sure you have 12 volts when checking pin 2 and use pin 1 for your ground.

https://www.2carpros.com/articles/how-to-test-an-oxygen-sensor-02-sensor

The resistance does sound high but let's start with this.

The fuel trims are just going to be a different way of showing these voltage readings so once we figure this out, those should come into line.

However, before we do anything, we need to check for codes. That is going to tell a clear story if we have an issue here. If you unhooked the sensors, then we may need to clear the codes and then operate the vehicle to see what codes come back or they could lead us down the wrong path if the codes were set when you had the sensors unplugged.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

See the diagram below of the connector for pins and let me know what you find. Thanks
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Wednesday, December 1st, 2021 AT 6:56 PM
Tiny
ALPHASENTORY GALAXY
  • MEMBER
  • 41 POSTS
Hello KaseKenny1,

Pontiac vibe o2 sensor reads on the ohms meter 24.0 ohms, on sensor side of harness. It is supposed to be 50 to 60 ohms, is it not? Perhaps this normal reading?

Voltage reading on ECM side of harness, reads on the four wire o2 upstream: first reading with voltmeter was 0.5, top right wire, this is the 5-volt reference telling me computer is alive.

Bottom right reads 9.389 volts, this is a voltage drop. The third wire is next wire, it reads 9.08 volts, another voltage drop from ECM, this one confused me, it appears there are two power wires dropping in voltage.

The fourth wire top left reads 0.0 volts there must be the ground wire. I was afraid to use the test light on battery positive to test the ground did not want to burn a transistor inside ECM.

The diagnostic tool reads on O2, 3.89 volts fluctuate but never goes down to 01.00 volts or 0.8 volts.

When performing o2 sensor test upstream OBD tool, says it passes, I do not know what to make of it.

I did not check downstream O2 with voltmeter did not want to lift the car in cold weather yet on live data it reads 0.787 volts does not fluctuate it is steady. In past reading it was stuck at 0.0 volts, it is moving wire or opening throttle it will sometime read normal.

Respectfully,
galaxzy andrameda (alphasentory)
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Sunday, December 26th, 2021 AT 1:36 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Okay. The numbers we need to focus on are what the scan tool is reading as the o2 sensor voltage. However, the voltage that you are getting doesn't seem right, so I suspect that is a voltage return wire and not the signal wire.

This voltage when using the scan tool should be moving slightly and bouncing around.45 volts. I suspect the voltages that you are getting are either a meter issue or the o2 sensors are failed.

Can you get a video or what these fuel trims are doing that you described in the first post? Also, do you actually have an issue with the vehicle or are you just trying to make sense of these numbers?
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Monday, December 27th, 2021 AT 3:31 PM
Tiny
ALPHASENTORY GALAXY
  • MEMBER
  • 41 POSTS
Hello Kasey Kenny,

I hear what you are saying, 'voltage return, ' means ECM has an internal resistor that protects the circuit. I forget what it's called.

All four wires from left to right were tested on the control side of ECM; then tested on the sensor side with ohm meter. Meter pos and neg were tested from top left to right top and bottom left to bottom right and diagonally crisscross in x configuration, I cannot remember when ohms read 0.24 ohms. I did get a 0.1289 resistance which dropped to 00 or OL the first time tested.

What I did not do was connect voltage meter setting to harness side (ECM) to connector terminals unplugged to read ECM's voltage readings to the sensor.

On live data streaming, short-term, long-term fuel trims upstream reading read high 3.89 volts with little fluctuations never going down to 0.45 to 7, 80 volts never dropping down less than 1 volt.

The car upon acceleration sounds rough, never reaching full trusting power, it races loud yet the car engine never thrusts its power on accelerator pedal.

Engine power is slightly compromised when accelerating without thrusting power.

I may have repeated the test again and relearn and review. I think it needs a new o2 sensor because it would pull a false code p0704 ECM performance, there is nothing wrong with ECM.

I am more baffled now than before.
Respectfully,
Alphasentory Galaxzy

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Wednesday, December 29th, 2021 AT 10:46 AM
Tiny
KASEKENNY
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Haha. I understand. These things are confusing. I agree that if these readings are not scan tool issues, then you need a new sensor.

However, short term fuel trims are not voltage readings. They are percentages. So, if you have 3% then that is ok because it is slightly lean but not that bad.

If you are slightly down on power and the engine is running slightly lean, then that could be a vacuum leak.

Does it run rough at all?

I would suggest getting a picture of the scan tool so that I can see these numbers that you are looking at and we can go from there.

Below is a chart that helps explain fuel trims. Keep in mind this is a calculation based on the o2 sensor voltage readings, but the fuel trim numbers are a little easier to look at.
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Wednesday, December 29th, 2021 AT 11:05 AM
Tiny
ALPHASENTORY GALAXY
  • MEMBER
  • 41 POSTS
Hello KaseyKenny,

You have been a great mentor supporting me through this arduous task of differentiating fuel trims percentages and O2 mvolts readings. I am grateful to you and your entire staff they have helped me work through twenty issues on the Toyota corolla 2000 and now the vehicle listed above, o2 sensors.

The Pontiac vibe repeats a false code po607 computer performance undefined nonspecific.
Even though I have checked for vacuum leaks with soap and water and clean the throttle body and PCV this code repeats every two months. The 5 volt reference is present in throttle body circuit computer is not dead that is why it is a false code PO607 or 601, I cant remember well.

The weather is cold in NJ now, I work outside not in doors. I will attempt to video tape all of my testing with voltmeter and obd live data results to you, I would enjoy this learning experience with you mentoring through these complex engineering designed circuits.

I have diagnostic textbooks on hand self learning does not make me a mechanic, I know enough to seek expert assistance.

In cold weather I am not very motivated to work on the car because I am older and a World Trade center first responder with several injuries. It will take me a while to resume with you, until then to all the empowering mechanics on car pros thank you for empowering the nation and for keeping economy functioning your services empower the john does.

Respectfully,
Alphasentory Galazxy
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Monday, January 10th, 2022 AT 9:14 AM
Tiny
KASEKENNY
  • MECHANIC
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This code is not going to be related to the o2 sensor issue unless you find an issue with the 5 volts. However, you would need to have this code active in order to find and issue with it.

I doubt it is a false code. I suspect it is an active code, but the issue happens quickly and then stops and so the code goes to stored. So, when you test the issue there is nothing wrong with it because it is not active.

So, I would suggest trying to test the 5-volt signal for a short to ground and if if you don't find one then the PCM needs to be replaced.

See the testing below. However, if we need to go more on this code then we need to get a new post started because this would not be related to this issue.

Thanks
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Wednesday, January 12th, 2022 AT 3:49 PM
Tiny
ALPHASENTORY GALAXY
  • MEMBER
  • 41 POSTS
Hello Kenny,

Yes, I got the info, thanks for differentiating between o2 and PCM. Do I check the 5-v reference at the throttle crank and cam sensors and at the computer?
I will open a new issue with you.
Respectfully,
Alphasentory
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Tuesday, January 25th, 2022 AT 12:35 PM
Tiny
KASEKENNY
  • MECHANIC
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I would check the 5-volt reference at any of the sensors that use it or the sensor that is setting the code.

The ECM sends the 5-volt reference to all sensors so if you have codes for only one sensor then more than likely the ECM is not the issue.

Let's get a new post started on that and we can go from there. Thanks
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Tuesday, January 25th, 2022 AT 12:47 PM
Tiny
ALPHASENTORY GALAXY
  • MEMBER
  • 41 POSTS
Video. Mp4.

Hello Kasekenny,

O2 sensor on Pontiac vibe 2009. Enclosed is live data on the short term and long term Furlings. Both trad high never reaching the zero mark. Open throttle o2 bank one is stuck 0.15 upon opening throttle it changes but never returns to 0. The cat converter bank one is hotter than converter two which reads 300. Bank 1 reads 0.15 remains stuck on.15. Hope you can make sense of the data. Respectfully,
Alphasentorygalaczy
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Friday, August 19th, 2022 AT 11:05 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
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With the PO607 code it says the ECM is working correctly and it needs to be replaced. Here is how, check the images below.

Powertrain Control Module Programming and Setup

PCM Replacement

Note:

- Replacement control modules are preprogrammed at the factory, and only require the VIN to be programmed. The VIN write procedure can only be performed with TIS 2 Web (SPS) using the MDI. Do not program a control module unless you are directed by a service procedure or by a General Motors Service Bulletin.

- Be advised that the Vibe Programming Application itself DOES NOT contain any calibrations. They are downloaded separately AFTER the Programming Application has been downloaded and installed on your PC.

If the PCM requires replacement, perform the following:

1. Ignition ON with a currently learned master key
2. Access Service Programming System (SPS). On the Select Diagnostic Tool and Programming Process screen, select J2534 Tech 2. Follow all on-screen instructions.
3. On the SPS Supported Controllers screen, select VIN-Write VIN to PCM (J2534). Follow the on-screen instructions.
Clear all codes and cycle the ignition OFF for at least 30 seconds.
4. Remove the scan tool and install a 3A fused jumper wire between terminal 4 and terminal 13 at the DLC.
5. Ignition ON for 30minutes.
6. After the 30 minute time period has elapsed, disconnect the jumper wire.
7. Start the vehicle and verify that the Security Light is not illuminated.
8. Clear all codes.

PCM Reprogramming

If the PCM requires reprogramming, refer to the following:

Downloading and Installation from TIS2WEB of the Vibe Programming Application to the PC

1. Use the following steps to create a New Folder on the Desktop to save the application files that will be downloaded and then installed on the PC:
1.1. Right click on Desktop.
1.2. Select New.
1.3. Select Folder.
1.4. Right click on the New Folder and rename it Pontiac Vibe.

2. Log on to TIS2WEB. In the upper right corner of the TIS2WEB Homepage, click on the Help menu question mark icon "?".
3. The Help dialog screen will appear. In the left column of the Help screen, click on VIBE Programming Application and Calibrations.
4. Click on Download VIBE Programming Application.
5. In the right column of the Help screen, under the heading Vibe Programming Application and Software Installation From TIS2WEB, observe the following statement:
You will need to download and install the VIBE Programming Application first.
Then,
5.1. Click (on the word) here (highlighted in blue) to download the latest VIBE Programming Application.
5.2. A File Download-Security Warning box will appear prompting to Run, Save, or Cancel. Click Save.
5.3. The Save As box will appear. Select Desktop for the Save in field.
5.4. Select the Pontiac Vibe folder.
5.5. Click Open. The Save in field will change from Desktop to Pontiac Vibe.

6. Double click on the Pontiac Vibe folder on the Desktop.
6.1. Double click on the vibe_app file.
6.2. The Open File-Security Warning Box will appear prompting to Run or Cancel. Click Run.
6.3. The WinZip Self Extractor will run, then the Vibe Programming Application-InstallShield Wizard box will appear, prompting for Next or Cancel. Click Next.
6.4. The next Vibe Programming Application-InstallShield Wizard box will appear, prompting for 6.5. The application will be installed and the last Vibe Programming Application-InstallShield Wizard box will appear, prompting to click Finish.
6.6. Click Finish to complete the application installation.

7. To access the application, double click on the new CUW Vibe Programming Icon on the Desktop. The application can also be accessed through the following menu path:
7.1. Click the Start Icon.
7.2. Select Programs.
7.3. Select Vibe Programming Application.
7.4. Select Vibe Programming.

You can get a rebuild unit on Ebay.
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Friday, August 19th, 2022 AT 11:51 AM
Tiny
ALPHASENTORY GALAXY
  • MEMBER
  • 41 POSTS
Live data o2 Pontiac vibe sensor checks out fuel trims voltage of o2 and the cat converters.
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Sunday, August 21st, 2022 AT 8:43 AM

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