[FIXED] P0133

[Stephen Carney]

I am helping my mom with her 2003 Hyundai Elantra. I recently purchased the BlueDriver OBD2 scantool. I ran into three codes, P0133, P0456, P0442. I have a break in the flex pipe that I believe is causing codes P0456, and P0442, both codes are EVAP system leak detected. For code P0133, the general consensus seems to be replacing the oxygen sensor. However, after scanning through her repair papers, the O2 sensor was replaced in 2014 and 2015, both to the tune of around $200. Any ideas as to what else can cause that code and what my next steps would be to find them.

Topic

[college man]

[quote=”scarney” post=181984]I am helping my mom with her 2003 Hyundai Elantra. I recently purchased the BlueDriver OBD2 scantool. I ran into three codes, P0133, P0456, P0442. I have a break in the flex pipe that I believe is causing codes P0456, and P0442, both codes are EVAP system leak detected. For code P0133, the general consensus seems to be replacing the oxygen sensor. However, after scanning through her repair papers, the O2 sensor was replaced in 2014 and 2015, both to the tune of around $200. Any ideas as to what else can cause that code and what my next steps would be to find them.[/quote]

Actually an exhaust leak will cause the p0133 not the other codes.

[Josh G]

[quote=”college man” post=181987]Actually an exhaust leak will cause the p0133 not the other codes.[/quote]

+1

Fix flex pipe then clear codes and recheck codes once the O2 monitor has completed

[Andrew Phillips]

[quote=”college man” post=181987]Actually an exhaust leak will cause the p0133 not the other codes.[/quote]
Another +1. Fix the exhaust leak first, erase the codes, let the O2 monitor run, then check the codes again. It’s doubtful your O2 sensor is bad, but possible there is corrosion/dirt where it plugs into the harness, so check and clean those areas. Every time you erase the codes it also clears the OBD monitors, so you won’t know right away if the O2 code comes back until after its monitor has run. You can research “drive cycles” for your vehicle to determine when each monitor runs. The evap codes are unrelated, and could be as simple as a bad fuel tank cap. However, they can also be caused by numerous other things. Look especially for cracked/rotted evap hoses between the engine bay and fuel tank, especially around the charcoal canister area.

[Stephen Carney]

I replaced the catalytic converter to fix the flex pipe. The code was still there however. I noticed that a stud was missing from the exhaust manifold. I put a new stud in, replaced the exhaust manifold gasket which ended up fixing the issue. Not after replacement, I still had the same code P0133. After some research, I found that sometimes its necessary to do a soft reset of the ECM by either pulling the fuse, or simply disconnecting the battery for a little while. Clearing the codes with the scan tool wasn’t enough. After doing a soft reset and completing a drive cycle the code was gone and replaced with P0420. I know the cat on the car if shot so I believe the code to be justified. On the replacing the cat. Thanks for your help everyone.

[Author]

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