srs airbag light tech stream cannot access srs system

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by terramir, Feb 22, 2018.

  1. terramir

    terramir Member

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    Ok, I have tried to check techstream this morning after the srs/airbag light stayed on, but it gives me the error that it cannot access the airbag/srs system and it turns white with a * on tech stream which means it is not there or it cannot access it.
    Anybody here have some troubleshooting steps for me, and if I need to where does the srs system live so I can go to the junk yard and pull another srs/airbag computer.
    terramir
     
    #1 terramir, Feb 22, 2018
  2. valde3

    valde3 Senior Member

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    Could your Techstream check the SRS system before? It could be a problem with cable. Check it with another car if you have not tested it before.

    If an ECU is really not talking, check all powers and ground to it and the communication lines between it and data link connector. If all those are ok then it’s the ECU. But as failures of these ECUs are rare other faults are more likely.
     
    #2 valde3, Feb 22, 2018
  3. terramir

    terramir Member

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    Where is that ecu? so I can check the lines. and how do I ground it to the communication lines?
    terramir
     
    #3 terramir, Feb 22, 2018
  4. ChapmanF

    ChapmanF Senior Member

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    What kind of dongle are you using with Techstream? The Mini-VCIs are very inexpensive but sometomes dodgy (I have one that won't pull engine ECU live data, or bleed the brakes more than one time in five). I tried another dongle (same laptop, same Techstream install), no issues.

    I believe the Gen 2 airbag ECU still had the fallback code reading method using a jumper wire and light blinks. You might look that up and try it; easy to do, and will get you some codes to start with, before you go to the trouble of digging down to the ECU.

    Or if you can't get it to even blink following the procedures in the manual, you'll have more evidence of it being just out of commission. (The repair manual can also answer your questions about where it is and how to get to it. It may be a bit buried....)

    -Chap
     
    #4 ChapmanF, Feb 22, 2018
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  5. terramir

    terramir Member

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    actually kinda funny the airbag system went back to functioning after I parked it in the sun yesterday, I think it might be a moisture related ground fault that is causing the problem. because now it's working again. But I have not tried to access the airbag computer yet via the miniVCI and yes I got the 1.xx version not the 2.xx version so that may be the problem. btw where does the airbag ecu live?
    terramir
     
    #5 terramir, Feb 23, 2018
  6. ChapmanF

    ChapmanF Senior Member

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    I'd have to look that up on techinfo, but my subscription isn't paid up at the moment so it'd be just as easy for you. If I remember right it's pretty low to the floor and far forward under the middle of the dash, what I meant by "may be a bit buried."

    With the Mini-VCIs I am not sure it is all about the version, but also just plain quality control. At the price point they're building for, some don't have issues and some do, even of the same version.

    -Chap
     
    #6 ChapmanF, Feb 23, 2018
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