: Which o2 sensor??



shent69
12-06-03, 09:26 PM
1996 Seville

I have "Service - Emissions" display. Pulled the code and got PC1139 which I think is:

DTC P1139 - Heated Oxygen Sensor (HO2S) Insuff. Switching Bank 1 Sensor 2

My question is what does it means and which sensor is that exactly so I can work on it? I haven't checked the wires yet but I am assuming that if the wires look okay I will need to replace it.

I wish I found this forum earlier. I learned more in the two days searching then the 2 years I had the car :bouncy:



~Scottie

cadillac6
12-09-03, 03:37 PM
I have a similar problem i dont know whats up with mine, i get codes for all 4 of my heated o2 sensors. I replaced all 4 and it still comes up?? what the hell is the deal?

epanightmare
12-11-03, 11:22 PM
1996 Seville

I have "Service - Emissions" display. Pulled the code and got PC1139 which I think is:

DTC P1139 - Heated Oxygen Sensor (HO2S) Insuff. Switching Bank 1 Sensor 2

My question is what does it means and which sensor is that exactly so I can work on it? I haven't checked the wires yet but I am assuming that if the wires look okay I will need to replace it.

I wish I found this forum earlier. I learned more in the two days searching then the 2 years I had the car :bouncy:



~Scottie

DESCRIPTION
Four Heated Oxygen Sensors (HO2S) are mounted in the exhaust system where they monitor the oxygen content in the exhaust stream. There is an oxygen sensor mounted in each exhaust manifold and one on each end of the catalytic converter. The oxygen sensor located in the front exhaust manifold is the Bank 2 Sensor 1 (Front) sensor. The oxygen sensor located in the rear exhaust manifold is the Bank 1 Sensor 1 (Rear) sensor. The oxygen sensor located in the Y-pipe ahead of the catalytic converter is the Bank 1 Sensor 2 (Pre-converter) sensor. The oxygen sensor located in the catalytic converter outlet is the Bank 1 Sensor 3 (Post-converter) sensor.

OPERATION
An oxygen sensor acts like a battery because it creates its own signal voltage once it reaches operating temperature. This voltage is produced when the oxygen content in the exhaust stream is different than the oxygen content in the atmosphere. A lean condition (high oxygen content in exhaust) will produce a low voltage (near 0 volts) and a rich condition (low oxygen content in exhaust) will produce a high voltage (near one volt). The PCM provides a reference signal voltage (0.45 volt) and a ground to the sensor. The PCM reference voltage is necessary because the oxygen sensors do not provide their own voltage until they reach operating temperature.

HEATING ELEMENT
The oxygen sensors also incorporate a heating element inside of the sensor housing. This heating element is energized with the ignition On and allows the sensors to reach operating temperatures quickly. The PCM can then use oxygen sensor information sooner after engine start-up.

PCM INPUTS
The PCM uses oxygen sensor information during Closed Loop operation to constantly adjust fuel control to reduce exhaust emissions. Because the oxygen sensors provide information sooner after engine start-up, exhaust emissions are reduced. Faulty oxygen sensors will cause various driveability conditions and will set a DTC.

hope this helps:bouncy:

stswillie
12-11-03, 11:56 PM
1996 Seville

I have "Service - Emissions" display. Pulled the code and got PC1139 which I think is:
~Scottie

Hey Shent69,

I also have a 96 seville STS. How did you pull the codes. Did you do it through the DIC(Driver Informatin Concole) aka buttons on the dash like "Info" and "Trip Reset"

OR

Did you have one of those handy OBDII code reader computer that you plug in by the E-brake pedal. I you used one of those little hand held devices where did you get it, how much did it cost, and are you happy with it.

Thanks and :welcome: to the forum

mike98c
12-18-03, 08:47 PM
I have a similar problem i dont know whats up with mine, i get codes for all 4 of my heated o2 sensors. I replaced all 4 and it still comes up?? what the hell is the deal?I have seen posts on other forums where people who replaced o2 sensors with aftermaket ones like Bosch ended up using the AC Delco ones to cure the problem, (although it certainly could be some other problem) also did you have the code cleared (either with a scanner or by disconnecting the battery for a while) and then it reappeared?

Qcaddy
12-30-03, 03:51 PM
DESCRIPTION What are the driveability condition for the oxygen sensors .I would like to compare mine, could this proble occur from bad or differen fuels.

Four Heated Oxygen Sensors (HO2S) are mounted in the exhaust system where they monitor the oxygen content in the exhaust stream. There is an oxygen sensor mounted in each exhaust manifold and one on each end of the catalytic converter. The oxygen sensor located in the front exhaust manifold is the Bank 2 Sensor 1 (Front) sensor. The oxygen sensor located in the rear exhaust manifold is the Bank 1 Sensor 1 (Rear) sensor. The oxygen sensor located in the Y-pipe ahead of the catalytic converter is the Bank 1 Sensor 2 (Pre-converter) sensor. The oxygen sensor located in the catalytic converter outlet is the Bank 1 Sensor 3 (Post-converter) sensor.

OPERATION
An oxygen sensor acts like a battery because it creates its own signal voltage once it reaches operating temperature. This voltage is produced when the oxygen content in the exhaust stream is different than the oxygen content in the atmosphere. A lean condition (high oxygen content in exhaust) will produce a low voltage (near 0 volts) and a rich condition (low oxygen content in exhaust) will produce a high voltage (near one volt). The PCM provides a reference signal voltage (0.45 volt) and a ground to the sensor. The PCM reference voltage is necessary because the oxygen sensors do not provide their own voltage until they reach operating temperature.

HEATING ELEMENT
The oxygen sensors also incorporate a heating element inside of the sensor housing. This heating element is energized with the ignition On and allows the sensors to reach operating temperatures quickly. The PCM can then use oxygen sensor information sooner after engine start-up.

PCM INPUTS
The PCM uses oxygen sensor information during Closed Loop operation to constantly adjust fuel control to reduce exhaust emissions. Because the oxygen sensors provide information sooner after engine start-up, exhaust emissions are reduced. Faulty oxygen sensors will cause various driveability conditions and will set a DTC.

hope this helps:bouncy: