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1995 S-10 4WD O2 Sensor Help

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  #1  
Old 12-20-2008, 11:39 PM
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Default 1995 S-10 4WD O2 Sensor Help

My check engine light went on after a recent snow storm so I decided it was time to scan to see what error codes came up.

I got back 3 codes:

P0135 - Bank 1 Sensor 1

P0138 - Bank 1 Sensor 2

P0141 - Bank 1 Sensor 2


I know where these sensors are on the pipes, but which is which? Is Sensor 1 before the catalytic converter or after? and vice versa??

Any immediate help would be great. I already bought a Bosch Sensor that is labeled as a pre-cat sensor, but cannot seem to find the other sensor... Are they they same?
 
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Old 12-21-2008, 07:15 AM
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Default RE: 1995 S-10 4WD O2 Sensor Help

Anyone know? I am driving 12 hrs tomorrow for the holidays and was hoping to get these sensors in today....

I know this is a noob question, but any help would be great!
 
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Old 12-21-2008, 07:55 AM
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Default RE: 1995 S-10 4WD O2 Sensor Help

ORIGINAL: swartlkk

B1S1 is a different sensor than B1S3. I believe the front sensors are an AFS105 (I can check that later against the packages still on my shop bench).

Typically a heater malfunction is a sensor fault and will come back after each complete drive cycle after clearing the codes. GM Drive Cycle

B1S1 is the drivers side sensor and B2S1 is the passenger side. B1S1 always coincides with the #1 cylinder on the engine.

Good luck and let us know.
quick search of these forums turned this up it at least tells you which side is bank 1 and this thread explains which is sensor 1 and which is 2 https://blazerforum.com/m_32538/tm.htm i knew swart had explained it a few times on here somewhere just took a minute to find the right thread hope it helps
 
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Old 12-21-2008, 03:01 PM
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Default RE: 1995 S-10 4WD O2 Sensor Help

Please try to be a bit more patient. While you may be in a hurry, having patience goes a long way to getting your problem resolved.

A quick look under your truck would yield the answer to your question. Given that you have provided OBD2 codes, your truck has the VCM-A engine management computer. As such, you will have two O2 sensors, a pre-cat sensor (B1S1) and a post-cat sensor (B1S2). The pre-cat, or upstream sensor as it is called is for fuel management only. The post-cat sensor is for catalyst monitoring only.

Here is a picture of your exhaust system:


This applies for the mid-late 95 model year with the VCM-A computer only as the earlier PCM style engine management with OBD1 codes only had one O2 sensor which was located in front of the catalytic converter and used for fuel management only.

The information provided by Outsydr is for the 96+ vehicles which have two upstream fuel management sensors (B1S1 & B2S1), one pre-cat catalyst monitoring sensor (96-97 only - B1S2), and one post-cat catalyst monitoring sensor (B1S3 or sometimes B1S2 in the 98+ vehicles depending on programming).

Hope this helps!
 
  #5  
Old 12-23-2008, 04:32 PM
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Default RE: 1995 S-10 4WD O2 Sensor Help

Perfect!

I had to ask because I was leaving the next morning on a 12hr drive and wanted to get the 2 new sensors in the evening before. Thanks for all your help, the new sensors are in and codes are cleared!

Thanks everyone
 
  #6  
Old 01-01-2009, 08:31 PM
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Default RE: 1995 S-10 4WD O2 Sensor Help

ORIGINAL: swartlkk

Please try to be a bit more patient. While you may be in a hurry, having patience goes a long way to getting your problem resolved.

A quick look under your truck would yield the answer to your question. Given that you have provided OBD2 codes, your truck has the VCM-A engine management computer. As such, you will have two O2 sensors, a pre-cat sensor (B1S1) and a post-cat sensor (B1S2). The pre-cat, or upstream sensor as it is called is for fuel management only. The post-cat sensor is for catalyst monitoring only.

Here is a picture of your exhaust system:


This applies for the mid-late 95 model year with the VCM-A computer only as the earlier PCM style engine management with OBD1 codes only had one O2 sensor which was located in front of the catalytic converter and used for fuel management only.

The information provided by Outsydr is for the 96+ vehicles which have two upstream fuel management sensors (B1S1 & B2S1), one pre-cat catalyst monitoring sensor (96-97 only - B1S2), and one post-cat catalyst monitoring sensor (B1S3 or sometimes B1S2 in the 98+ vehicles depending on programming).

Hope this helps!

It helped! All fixed up and I am actually getting somewhat decent gas mileage! Thanks everyone!
 
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