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check engine light and P2238 P3000 codes

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by prius4ed, Mar 9, 2011.

  1. prius4ed

    prius4ed Member

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    My check engine light comes on and then goes out occasionally. I bought a scanner at Walmart for $100 and connected it to the DLC. It reads P2238 and P3000 codes. Any help on what to check? I think P2238 means it's running lean. I'm hoping it's simple. Thanks in advance.
     
    #1 prius4ed, Mar 9, 2011
  2. seilerts

    seilerts Battery Curmudgeon

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    P2238 is the upstream o2 sensor (A/F sensor). Maybe it is a wiring problem due to the accident or reconstruction? If you have to remove this sensor, please post the socket that you used. OTC makes one specifically for select Toyotas for $75. I had to grind the outside of a cheapie o2 socket to get it to fit. See http://priuschat.com/forums/gen-ii-...ting/89967-oxygen-sensor-collar-around-3.html

    P3000 is a general HV battery fault. How long was the car sitting before you got it running again? Have you had any problems with the car losing power when it codes?
     
    #2 seilerts, Mar 10, 2011
  3. prius4ed

    prius4ed Member

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    I would guess the wiring is ok, b/c after I fixed everything I drove the car daily for about a month without any check engine light. It only recently started coming on, and later it would go out, etc. I will check the wiring again. There is a procedure for checking the A/F sensor, isn't there? Checking the ohms on the leads I think. Where is the A/F sensor located and it's connector? I'm guessing on the exhaust manifold, the most upstream sensor on it, and accessed from under the car?
     
    #3 prius4ed, Mar 10, 2011
  4. prius4ed

    prius4ed Member

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    how to test the A/F sensor? Can it be repaired?

    Also, if the A/F sensor is bad, can it be cleaned somehow (heat with propane torch, etc) to get it working again? I'm guessing not, since it's heated by the exhaust when it's installed and in use.
     
    #4 prius4ed, Mar 10, 2011
  5. seilerts

    seilerts Battery Curmudgeon

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    It's all underneath. Take a look at picture below for the A/F sensor location (see O2 socket) and connection. There's not a whole lot to troubleshoot here. You can check the resistance at the sensor to see if there is a problem with the heating element, should be 2-3 ohms. I think you need a bidirectional scan tool to adjust injector volume and see if the sensor output changes accordingly. If it is not the sensor, then it is either wiring harness/connectors or ECM.

    [​IMG]
     
    #5 seilerts, Mar 11, 2011
  6. prius4ed

    prius4ed Member

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    Thanks for the reply and photo of the A/F ratio sensor. In the photo, are we looking up from under the car? How can we determine the sensor is faulty, besides the 2-3 ohm connector check (which leads, please?)? Is there a way to clean the sensor? Mine is acting bad only sometimes; the CEL goes on one day and the next day it's out.
     
    #6 prius4ed, Mar 11, 2011
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