- Aug 28, 2012
- 20
I keep getting P1133 and P0136 DTC codes on my 2004 Chevy trailblazer with I6 engine. Originally I went to autozone and got a bosch. Yes i know get ac delco. Then i bought AC delco one from rockauto, and that is what is currently in the vehicle. I finally got motivated enough to do some in depth digging into the issue at hand. I am an EE so I used an oscilloscope to measure the upstream o2 sensor data in real time. I also have a OBD tool but you can't resolution as good as you can with an scope. Below I have posted the testing of 2 different upstream o2 sensors at idle and at 2000RPM.
Major question I have is how fast should the o2 sensor be switching from rich to lean at idle and at 2000rpm? From these graphs at idle its switching at 0.2Hz and at 2000rpm is switching at 0.5Hz. How fast should these be switching on a trailblazer? Any help would be greatly appreciated! Thanks
1st picture is bosch sensor at idle
2nd picture is bosch at 2000rpm
3rd picture is ac delco at idle
4th picture is ac delco at 2000rpm
5th picture is heater circuit
Major question I have is how fast should the o2 sensor be switching from rich to lean at idle and at 2000rpm? From these graphs at idle its switching at 0.2Hz and at 2000rpm is switching at 0.5Hz. How fast should these be switching on a trailblazer? Any help would be greatly appreciated! Thanks
1st picture is bosch sensor at idle
2nd picture is bosch at 2000rpm
3rd picture is ac delco at idle
4th picture is ac delco at 2000rpm
5th picture is heater circuit