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Prius will start but with no dash, a/c, power steering, etc...

Discussion in 'Gen 2 Prius Technical Discussion' started by inderocker, Jan 26, 2019.

  1. inderocker

    inderocker Junior Member

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    Hi all, I've been having an odd issue with my Prius ever since I bought it back in Oct 2018. Every once in awhile, when I power it up, the engine will start (roughly 15 seconds after initiating with the power button and foot on the brake), but the dash will not be illuminated at all, the power steering will not be functioning, and the A/C & heat will not work. The information display will light up, but the hybrid "bars" are not displayed. The brakes seem to function normally, but I just read that they have a battery backup. It is similar to hitting the power button without having your foot on the brake, only the engine will start and you can drive it.

    The vehicle signal check has showed low voltage, down to low 10's while driving once upon a time (dash lit up like a Christmas tree and a buzzer sounded after an emergency/hard braking incident, voltage checked promptly after), so I have a replaced the chassis battery with a new glass mat unit and replaced the inverter coolant pump due to a P0A93 code it threw. I've had it at my local Prius specialists shop, but he is stumped on the issue. The occurrence of the issue has increased this month as well. It'll usually do it on at least 1 start up per day now, whereas before it could take a couple weeks.

    Any ideas?
     
    #1 inderocker, Jan 26, 2019
  2. bisco

    bisco cookie crumbler

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    welcome!

    start with a reading of the trouble codes by someone with a copy of tech stream diagnostic software, then post them here.
     
    #2 bisco, Jan 27, 2019
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  3. jerrymildred

    jerrymildred Senior Member

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    Sounds like you might have an inverter issue, but that's just a semi-educated guess. As @bisco said, you need the codes read by Techstream or another Prius fluent code reader.
     
    #3 jerrymildred, Jan 27, 2019
  4. inderocker

    inderocker Junior Member

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    I got a print out from my mechanic the last time I was in. It showed 3 codes, P3108, U0129, and C1242.
     
    #4 inderocker, Jan 28, 2019
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  5. bisco

    bisco cookie crumbler

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    did he tell you the code meanings?
     
    #5 bisco, Jan 28, 2019
  6. inderocker

    inderocker Junior Member

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    P3108 - Lost Communication With A/C System Control Module
    U0129 - Lost Communication With Brake System Control Module
    C1242 - Open Circuit In IG1/IG2 Power Source Circuit
     
    #6 inderocker, Jan 28, 2019
  7. dolj

    dolj Senior Member

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    Were all codes cleared after the 12 V battery was replaced? If they weren't you need to clear the codes and see what comes back.

    While the codes you mentioned don't really point to it, your symptoms made me think failing combination meter.

    You may have a couple of things going on here, but check this thread (T-SB-0172-09 Combination Meter - Intermittent Display | Page 6) and see whether you (or your mechanic) need to fit a refurbed CM.

    There is also this thread (Combination Meter repair - DIY) which details how to repair if you want to attempt that – Post #71 (on page 4) has a nice summary of what needs to be done., or else there is the option to purchase a repaired CM from Matt @Texas Hybrid Batteries

    Hope that helps.
     
    #7 dolj, Jan 28, 2019
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  8. dolj

    dolj Senior Member

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    Not wanting to seem like I'm nit picking, but the fortune cookie text for P3108 is A/C Amplifier Communication Circuit Malfunction. Lost comms is different to comms circuit malfunction, even if that difference is subtle.

    There 5 sub (or INF) codes associated with this DTC.
    DTC No. Detection Item DTC Detection Condition Trouble Area Master Warning Light MIL Memory
    1 P3108-535 A/C Amplifier Communication Circuit Malfunction Serial communication malfunction
    • Wire harness or connector
    • Inverter with converter assembly
    		 - - DTC stored
    2 P3108-536 A/C Amplifier Communication Circuit Malfunction A/C inverter malfunction
    • Wire harness or connector
    • Inverter with converter assembly
    		 - - DTC stored
    3 P3108-537 A/C Amplifier Communication Circuit Malfunction Air conditioning amplifier malfunction
    • Air conditioning amplifier
    		 - - DTC stored
    4 P3108-538 A/C Amplifier Communication Circuit Malfunction Open in STB signal circuit
    • Wire harness or connector
    • Inverter with converter assembly
    		 - - DTC stored
    5 P3108-594 A/C Amplifier Communication Circuit Malfunction CAN communication malfunction
    • CAN communication system
    		 - - DTC stored


    DTC P3108 (INF 594) is one of the DTCs that indicate CAN communication malfunction.
    Since the air conditioning amplifier is connected to BEAN (Body Electronics Area Network), the HV control ECU communicates with it using CAN (Controller Area Network) communication via the gateway ECU.

    When DTCs other than CAN communication malfunction DTCs are output simultaneously, first correct the CAN communication problem, and then perform troubleshooting for other DTCs.

    Hope that helps, if those DTCs are really still current.
     
    #8 dolj, Jan 29, 2019
    Last edited: Jan 29, 2019
  9. inderocker

    inderocker Junior Member

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    Yes, codes have been cleared several times since the battery was replaced. Would a combination meter issue like that cause the rest of the electrical components not to work?
     
    #9 inderocker, Jan 29, 2019
    Last edited: Jan 29, 2019
  10. inderocker

    inderocker Junior Member

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    20190129_094000.jpg
    Welp, I'm at a loss for that. That's what it says on the print out. It also shows detail code "535".
    It also shows detail code "220" and "528"
     

    Attached Files:

    #10 inderocker, Jan 29, 2019
    Last edited: Jan 29, 2019
  11. inderocker

    inderocker Junior Member

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    Sorry those photos didn't come out too legible.
     
    #11 inderocker, Jan 29, 2019
  12. inderocker

    inderocker Junior Member

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    I forgot to mention that every time it has done this, eventually the car will come to life (dash, power steering, etc). I've timed it on several occasions and it'll take anywhere from 45-90 seconds until I hear a relay click and everything comes on.
     
    #12 inderocker, Jan 29, 2019
  13. dolj

    dolj Senior Member

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    Those detail codes are for your U0129.

    DTC No. INF Code DTC Detection Condition Trouble Area
    1 U0129 220 CAN communication problem between skid control ECU and HV control ECU (no signal input)
    • CAN communication system
    2 U0129 528 CAN communication problem between skid control ECU and HV control ECU (transmission error)
    • CAN communication system

    It is hard to say for sure from a distance. But, the MFD and the CM both use the Gateway ECU to communicate with each other.

    In light of the fact that these have continued to be present, it would be sensible to start troubleshooting them first.

    In general, lost comm errors always advise to check the plugs, harness wiring and then finally the associated ECU. It assumes that the 12 V supply has already been checked and is always suppling voltage in the range 10-14 V.

    Here are the repair manual workups:

    Work up for DTC U0129 Refers to CAN COMMUNICATION SYSTEM (page 05–2602)
    You will see that there are several references to other sections of the Repair Manual and it is not feasible for me to provide links to all of them. If you are not put off and are eager to continue to trouble shoot this DTC, then I suggest you find a downloadable copy of the repair manual (search this site for the 2006 Repair Manual and Electrical Wiring Diagram) or take a 2 day or 1 month subscription to the techinfo.toyota.com

    Work up for DTC P3108
    Work up for DTC C1241/41 & C1242/42

    Gook luck with your troubleshooting.

    Keeps us updated with how you tackled these DTCs.

    Hope that helps.
     
    #13 dolj, Jan 29, 2019
    Last edited: Jan 29, 2019
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  14. silversluggen2

    silversluggen2 New Member

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    ive had this same exact issue happen to me today. Can you tell me what the issue was? Thanks in advance
     
    #14 silversluggen2, Apr 30, 2019
  15. inderocker

    inderocker Junior Member

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    Sorry for the delayed reply, it was a bad master relay.
     
    #15 inderocker, Jun 23, 2019
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  16. Aron613

    Aron613 New Member

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    I’m having this exact problem
    Where is the master relay?
     
    #16 Aron613, Aug 14, 2019
  17. Falcon Hybrid

    Falcon Hybrid Junior Member

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    where is the master relay found?
    we have a car with the exact same issue
     
    #17 Falcon Hybrid, Sep 4, 2019
  18. jerrymildred

    jerrymildred Senior Member

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    If by "master relay," you mean the relay that connects the HV battery to the rest of the car when you put it in READY mode, it's inside the battery housing. The orange wires from the battery connect to one side and the orange wires to the car connect to the other side. Pretty obvious once you take the cover off the battery.
     
    #18 jerrymildred, Sep 4, 2019
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  19. SFO

    SFO Senior Member

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    :coffee:
     
    #19 SFO, Sep 4, 2019
    Last edited: Sep 5, 2019
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