Error Codes p0133 and p0134 – How to Replace O2 Sensor (Upstream)
This article describes how to replace the upstream O2 sensor which eliminates the p0133 p0134 error codes on a 2004 Toyota Corolla.
I was getting a check engine light with error code P0133 and P0134 in the 2004 Toyota Corolla CE with manual transmission. This description also applies to 2003, 2005, 2006, 2007, and 2008 Toyota Corollas.
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What Causes a p0133 and p0134 Error Code?
It turns out that these error codes refer to the upstream oxygen sensor not responding and replacing the faulty o2 sensor will fix the problem. Issues with the downstream oxygen sensor are usually accompanied by a P0420 error code.
Tools and supplies needed:
- flat screwdriver
- 12mm socket
- 22mm wrench
- oxygen (o2) sensor
Steps to Fix P0133 and P0134 Error Codes
First, locate the upstream o2 sensor. Open the hood, it is near the back against the firewall.
Use a flat screwdriver to pull up the tab and unplug it.
Had to remove the heat baffle (4 bolts 12 mm) to get at the place to unscrew the old sensor.
Remove the old O2 sensor. The sensor itself requires a 22mm wrench (7/8″ would probably be close enough). They make a special tool for this that may allow the removal/install without removing the baffle, but it isn’t too much effort to just remove the baffle and use an open-end wrench.
Turn it counter-clockwise in order to loosen and remove the sensor.
Initially, I took out the old one and sprayed it with throttle body cleaner, sanded off the roughness, and reinstalled. I reset the error code, and hoped this would solve the problem, but unfortunately it came back the next day.
So bought a new one and replaced it. This is the o2 sensor replaced that fixed the problem.
Error code stays off now.
I’ve had this one in for well over a year now. These error codes have not returned.
Thanks for reading, and I hope someone out there finds this helpful!
Rich
Tools and supplies used in this article:
- flat screwdriver
- 12mm socket
- 22mm wrench
- oxygen (o2) sensor
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what size wrench headis on the sensor?
Donald,
Good question, I must have spaced out and forgot to list that in the article for some reason (I will update that). The wrench size to get it out is 22mm. I suppose a 7/8″ would probably also work. Thanks for letting me know to include that!
Richard