I had the following engine codes

P1133 - HO2S Insufficient Switching Bank 1 Sensor 1
P0133 - O2 Sensor Circuit Slow Response Bank 1 Sensor 1
P0130 - O2 Sensor Circuit Bank 1 Sensor 1

The mechanics couldn't' figure out why after giving them $$$.

After reinstalling the ECM myself, (just taking it out putting it back in), the 02 sensor codes disappeared, but I still have the EVAP codes.

P0442 - EVAP System Leak Detected (small leak)
P0455 - EVAP System Leak Detected (large leak)

I think the EVAP codes might be the result of a faulty electrical system. What is the next step to take assuming the solution has something to do with the electrical system? I was thinking maybe

  • replacing a wire harness?
  • cleaning some connector pins?

I am not a mechanic. If simply resintalling the ECM solved my 02 sensor problem, maybe the EVAP problem is related to it somehow.

Any advice what component to replace/inspect next?


car model: Saturn Ion 2003

  • The next step is using a scan tool command all the evap relater solenoids and look at the evap pressure sensor. If all that checks out command the car to run an evap test.
    – vini_i
    Dec 30, 2016 at 12:40


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