My 2000 Buick Century 3.1 L gave me a code 140. It was recently replaced with an exhaust system replacement and that’s when I got the 140 code. The old sensor had given me a code indicating a problem in the sensor heater circuit. I was going to remove new the sensor, bank 1 sensor 2, and check resistances between the input leads and compare with the readings found in a new sensor from AutoZone to see if I obviously have a bad new sensor in my car. And, I had found the red wire to the sensor connector broken and spliced it. After clearing the code, the code 140 came back after about 20 minutes driving. But this time I did not get a sensor heater control circuit code. What might be a common cause for this code 140? Could an ohmmeter tell me about the status of this sensor? Should I check voltages going into the sensor? What should the voltages be?
Tester
Tester, thanks for your reply, yet.the video doesn’t talk about which wires to connect to. Might you know which ones for a 2000 Buick Century 3.1L?
The signal wire from the O2 sensor is purple with a white stripe.
The positive lead of the meter connects there.
The ground wire of the meter connects to the sensor itself.
I usually connect on the metal where the wires of sensor enter the sensor.
Tester
Thanks for this info
I got cheap o2 sensor. And got new different code. So I then got an Oem sensor and been good.
My scan tool.only gives me the code number which is described as no activity in this O2 sensor
It doesn’t give you live data?
If so, you’ve got a code reader and you need to step up and buy a scanner
Inspect the oxygen sensor heater fuse in the under-hood fuse box. Then test for power to the O2 sensor heater. It is possible to have no power to the O2 sensor heater and fault detection is delayed.