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ECM/ECU replacement procedure

Discussion in 'Gen 2 Prius Main Forum' started by Zv0829, Jun 4, 2023.

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  1. Zv0829

    Zv0829 New Member

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    2005 Prius
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    I have a P0038 code that doesn’t go away and according to one of the service manuals I need to replace the ECM. I pulled one from the junkyard from a same year prius (2005) because I thought I could just swap it out. I’m being told I’ll have to get a locksmith to reprogram the immobilizer? But from other chats on here it sounds like I might have to get the ECM reprogrammed as well? Any help is appreciated thank you.
     
    #1 Zv0829, Jun 4, 2023
  2. mr_guy_mann

    mr_guy_mann Senior Member

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    It's certainly possible that the ECM is faulty. Haven't seen it myself but there's a couple threads in the forums. Just be sure there's no damage to the wiring for the O2 sensor.

    What testing have you done for this code?

    It's preferable to get a replacement ECM that has the same part number as the old one (tough to read that off the ECM in place without a videoscope). But just having the same year car "should" be enough. (they were fairly cheap on ebay)

    On a Gen2 Prius the ECM is completely plug and play. No VIN programming, no immobilizer involvement. If you're careful, there's just enough slack in the wiring harness to flip the connectors around and plug the "new" ECM in without mounting it (so you can test it before removing the old one)

    Posted via the PriusChat mobile app.
     
    #2 mr_guy_mann, Jun 5, 2023
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