When I got my '00 4runner a little over a month ago it has code 1130/1135 which meant the front o2 sensor. I replaced it and that code has gone away. Now 3 times within about 200-300 miles of each reset I have gotten code 0402. I see that could be the rear o2, cats (it has a cali emissions), or exhaust leak. Before I go spend $65 on the new rear sensor is there wa way to test the rear sensor? I read somewhere, that I canot find now, to hold the rpm around 2500 and watch the voltages of the two sensors. However I cannot find where I read that again nor can I remember what the voltages should be. I have an elm327 bluetooth odb2 adapter with torque pro so I can monitor all that stuff.
Code 0420
- Thread starter kameleon
- Start date
Register to hide this ad
Mauzer
New member
Wait, do you have code P0420 or P0402? I'm guessing since your talking about your 02 sensors its P0420, Here is an article on how to check your sensor:
How to Check the Ohms on Your Oxygen Sensor | DoItYourself.com
You can also try soaking your cat (w/o the 02 sensor) in water & laundry detergent to try to clean any blockage (I've personally never done this but have heard it can work).
How to Check the Ohms on Your Oxygen Sensor | DoItYourself.com
You can also try soaking your cat (w/o the 02 sensor) in water & laundry detergent to try to clean any blockage (I've personally never done this but have heard it can work).
TheDurk
Elite Member
Actually, there is not much point to an ohm test for a P0420. The ECU does that test continuously, and if the sensor is out of spec, it will give a different code (P0141).
http://tacoma.site40.net/4Runner_96-02_Repair&Wiring/techinfo.toyota.com/ileaf/02toyrm/02toypdf/02rmsour/2002/024runne/di/eg5vzfe/cip0141.pdf
That said, a sensor can still degrade and be responsible for a P0420 without being out of spec on heater ohms, although you will find techs who deny this. I cured a P0420 by changing my rear O2. It had 110k anyway so it was time--I didn't sweat the diagnosis.
http://tacoma.site40.net/4Runner_96-02_Repair&Wiring/techinfo.toyota.com/ileaf/02toyrm/02toypdf/02rmsour/2002/024runne/di/eg5vzfe/cip0141.pdf
That said, a sensor can still degrade and be responsible for a P0420 without being out of spec on heater ohms, although you will find techs who deny this. I cured a P0420 by changing my rear O2. It had 110k anyway so it was time--I didn't sweat the diagnosis.
Last edited:
