Cadillac Catera and Cimarron Forum Discussion, 2001 Catera throttle body and O2 sensors in Past Cadillac Vehicle Discussion; Hi Folks,
If the throttle body is bad could it cause O2 sensors (bank1 sensor 2 and bank sensor 2) ...
If the throttle body is bad could it cause O2 sensors (bank1 sensor 2 and bank sensor 2) to act up and throw a CEL. I replaced the O2 sensor on one side but still getting code no heater circuit and other side I don't remember the description exactly but both were the O2 codes.
I ran a live data with my code reader and it was reading the O2s so not sure why it would say no heater circuit.
I only suggest that as a starting point just to rule out the oxygen sensors. If the codes don't change, then you can rule out the O2 sensors. You can also check that you have 12vdc on at least one of the wires on the connectors. If you don't you might have a blown heater ckt fuse. The heater ckt is separate from the sensor ckt which would explain that you are still getting a reading from the sensor.
Okay, thanks. How do I check for the 12vdc and where's this fuse located? Also, when the code P0161 (bank 2 sensor 2) came on at first I replaced the sensor with a new one from rockauto.com (APWI Part # AP4251) and then the next day CEL came on and it read two codes P0161 (bank 2 sensor 2) and P0140 (bank 1 sensor 2 heater circuit).
My question now is, could the new sensor (APWI part #AP4251) have cause this problem?
Make sure the key is off, then disconnect the O2 sensor at the connector. Turn the key on. With the black lead of the mulitmeter, find a good ground point on the chassis. Connect the red led to one of the pins on the connector that goes toward the engine. Check the pins until you find one with 12vdc. This is the heater voltage from fuse 43 in the ECM. Check the connector of the sensor on the opposite side as well. (don't worry about the fuse just yet)
Okay, thanks. I checked the voltage and getting 12vdc at both sides of the O2s so pretty sure the fuse is good. Also, the CEL came back on this morning after I turned it off last night. I scanned it this afternoon and it showed only P0140, bank 1 Sensor 2 heater circuit. Any idea where to go from here for this code?
Anyways, I swapped the sensors, cleaned the connectors and secured everything back. I'll let you know if CEL comes back on again.
After swapping the sides on the rear O2 sensors we drove around and there was no CEL. Then this morning the CEL came back and it read the same two codes P0140 - O2 Circuit No Activity Detected Bank 1 Sensor 2 and P0161 - O2 Heater Circuit Bank 2 Sensor 2. I checked voltage last night and it was reading 12Vdc at both connection.
Also, when I checked the resistance on the old O2 sensors it was showing 8.5 each whereas the new one from rockauto.com APWI part #AP4251 was showing a resistance of around 13.
I have no clue what to do now, either get another sensor for the other side and see if it'll fix the O2 issues or track some other problem in the system.
Also, should I stick with Bosch brand O2s or the APWI will be fine? I checked with rockauto and they said they have been selling APWI O2 brand for the past year and had no problems.
Chris Heath (RippyPartsDept) is an ASE Certified GM Parts Consultant at Rippy Automotive
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Just to clarify, on the sensor with the 161, with the old sensor, new sensor and the sensor from the other side on the connector, you are always getting code 161? What percent or voltage does your scanner read for the sensors. Is the new sensor a direct fit or universal?