For more on O2 sensor testing go to www.scannerdanner.com. This video covers some of the variables that can set a P0133 O2 slow response trouble code. What causes an O2 slow response trouble code? What does an O2 signal look like in open loop? How can you tell if a system is in closed loop? How to identify O2 sensor wiring without a diagram. O2 sensor frequency and amplitude testing. How to determine sensor location using scan data.