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OBD2 O2 Sensor Data variances
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WrenchPincher
User
Jun 15, 2023, 5:10 AM
Post #1 of 4
(1897 views)
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OBD2 O2 Sensor Data variances
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1999
Dodge
Grand Caravan
3.3L200,000+
I am trying to determine (from OBD2 Data) if there's a problem with my catalytic converter such as clogged. Below are small samples of OBD2 data from 2 different vehicles. Both PASS all emissions tests according to my ELM327. The 1999 Caravan has sat outside unused for 4 years. The fuel has been drained and refreshed. These sets of data were taken when both vehicles were at operating temperature.
The main reason for this concern is that the 1999 is running hot and I have yet to figure out why. But that is for another thread.
Below is a small sample of the raw OBD2 data for the 2 vehicles. I notice there are fluctuations away from the expected average value of around .5 - .7v on both vehicles but more so on the 1999. Is that "normal"?
I also have an xTool D8 scan tool but on the 1999 the ELM327 is actually more useful since the D8 is almost useless on the 1999 Caravan because it can't read anything other than OBD2 data and the ELM327 does a better job of that imo.
O2B1S2
(Volts)
From 1999 Caravan
0.47
0.61
0.57
0.49
0.17
0.81
0.81
0.47
0.39
0.38
0.38
0.57
0.82
0.79
0.06
0.17
0.55
0.67
0.21
0.72
0.65
0.77
0.72
0.04
0.67
0.72
0.74
0.63
0.70
0.74
0.81
0.77
0.67
0.79
0.26
0.08
0.81
0.10
0.81
0.79
0.79
0.82
O2B1S2
(Volts)
From 2006 Caravan
0.69
0.69
0.70
0.69
0.15
0.17
0.65
0.65
0.74
0.69
0.69
0.69
0.80
0.74
0.69
0.67
0.67
0.56
0.37
0.65
0.80
0.74
0.76
0.74
0.69
0.65
0.69
0.67
0.67
0.67
0.63
0.69
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Hammer Time
Ultimate Carjunky
/ Moderator
Jun 15, 2023, 6:02 AM
Post #2 of 4
(1892 views)
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Re: OBD2 O2 Sensor Data variances
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None of those voltages mean a damn thing.
They vary with conditions, outside temp, engine temp, PCM status, various sensor feedback, etc.
There are tests to determine if there is an exhaust restriction but the scan data won't tell you.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jun 15, 2023, 8:11 AM
Post #3 of 4
(1880 views)
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Re: OBD2 O2 Sensor Data variances
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Hmm - 2 different issues same vehicle. Seems running hotter and suspect exhaust restriction as HT mentioned could cause both. A lot of heat must go out exhaust freely.
Ask there are some easier or simply ways to know,
Tom
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Hammer Time
Ultimate Carjunky
/ Moderator
Jun 15, 2023, 9:09 AM
Post #4 of 4
(1874 views)
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Re: OBD2 O2 Sensor Data variances
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No, I didn’t say I thought it was causing the overheating. I said there are other ways to test for restricted exhaust if you need to.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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