C1310 156 - Need help on where to look

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by zonakicker, Sep 27, 2020.

  1. zonakicker

    zonakicker New Member

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    Hello,

    I'm struggling with conflicting information on where the Hybrid Control ECU is actually located. Getting the code C1310 (pics from techstream attached), but the car still drives fine. I cleared the codes and as expected it comes back after two miles with the red triangle, "problem" on the MFD and brake system warning.

    Here's what I've done so far after reading posts here or on the internet:
    • Pulled the hybrid battery to inspect the battery bus bars (all clean and shiny), no signs of corrosion
    • Reseated the connectors in the hybrid battery, the ones I could reach.
    • Installed the Prolong Harness from Hybrid Auto while I had it apart, reconditioned the battery
    • Bought and am using the Mini VCI and Techstream program off amazon
    I'm not a novice, have dived into a number of things on this car and intend to drive it until it's just dead or too expensive to fix. At some point in the last 5 years, replaced inverter, brake actuator assy, hybrid battery (rebuilt from Greentec Auto) - I'm ok getting into the car repairs.

    If I need to replace the Hybrid Control ECU, I'm good to go. I'm seeing that it could be behind and to the right of the glove box, or is it in the Hybrid battery? And - is that an appropriate next step?

    2004 Prius, has around 320k miles (ODO stopped at 299,999) and I'm the original owner.

    I appreciate any help you can provide.

    C1310 Code.jpg Clicked on Snowflake.jpg
     
  2. Raytheeagle

    Raytheeagle Senior Member

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    Research the detailed trouble code listed on your second screen shot (156);).

    That'll share the troubleshooting tree next steps :).

    Sounds like your 04 has been good to you(y).
     
  3. Elektroingenieur

    Elektroingenieur Senior Member

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    The hybrid vehicle (HV) control ECU is in the instrument panel, on the right side. The hybrid battery ECU is with the HV battery, behind the rear seats.
    The Repair Manual (more info) gives the detection condition for diagnostic trouble code (DTC) C1310: “The traction control prohibition signal is received for at least 0.07 sec. when IG2 terminal voltage is 10.5 V or more for at least 1.5 sec. and communication with hybrid control computer is valid.” That is, the skid control ECU received a report of a problem from the HV control ECU and stored DTC C1310 to record this fact.

    Since this DTC is being set, and the car can be driven normally, we can conclude that the HV control ECU is present, functioning, and able to communicate with the skid control ECU and the engine control module (ECM).

    We’re not getting a complete picture of the situation, however. For a 2004 Prius car, the Health Check Results table in the Techstream software should have entries for “Hybrid Control” and “Engine and ECT,” in addition to those seen in the first photo. The missing entries suggest that the vehicle interface module connecting the PC to the car is faulty or lacks the required capabilities—the most likely cause, especially if it’s an inexpensive one of dubious origin—or that something else is wrong with the Techstream software.

    In principle, a Techstream communications failure could indicate a problem with the car’s wiring, but I think that’s unlikely in this case, since there appears to be valid CAN communication among the HV control ECU, skid control ECU, and ECM, and between Techstream and other ECUs, such as the hybrid battery ECU.
    That’s usually an excellent idea, but the inspection procedure for DTC C1310 has only one step: “Check Hybrid Control System.” In other words, there should be one or more additional DTCs stored in the HV control ECU, and those DTCs should give you an idea of the actual problem—but since Techstream doesn’t seem to be communicating with the HV control ECU, it’s not showing them in the Health Check Results.
    I wouldn’t replace any ECUs at this point.

    You need a Techstream system that works properly. You could buy an official Techstream Lite kit, or roll the dice again on a different eBay, Amazon, or AliExpress seller. Once you can see the DTCs stored in all of the car’s computers, turn again to the Repair Manual, as @Raytheeagle kindly suggests.
     
  4. zonakicker

    zonakicker New Member

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    Elektroingenieur,

    Thank you - that's helpful. When I go back a page on Techstream, it does show that it is not communicating with Engine and ECT, or Hybrid Control ECU's. It's a brand new install, will try restarting the laptop to see if I get a different result. Sounds like I may need to take it in to have someone pull the codes and get the fuller picture.

    Luckily, I purchased a 2008 Prius last year that needed a brake assembly also as a back up car - and it's running great right now. So, I have time to sort this out.

    Ray - I've been looking for the detail trouble code since last night...still looking. The truth is out there, somewhere. The 2004, has been a good car for us - my wife prefers it to the newer one even.
     
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  5. zonakicker

    zonakicker New Member

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    New information! Restarted the laptop, updated Java and it's getting the Engine and ECT and Hybrid Control ECU's now. Surprised? Me too...

    P3009 with detail codes 526, 612
    C1310 with detail code 156

    I pulled up the P3009 DTC diagnistics pages from PriusChat, it looks like I go to Step 5 and check the HV Battery Area. Checking the insulation resistance. Does that sound like I'm on the right track? Looks like I might bounce around that document a little. Looks like it's something in the HV battery area, or one of the connections to the inverter.

    Pics of the Techstream are attached.
     

    Attached Files:

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  6. Elektroingenieur

    Elektroingenieur Senior Member

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    Basically, yes, though the unofficial copies of the procedure may be out of date. In later editions, which may have different step numbering, step 1, alternative A (P3009 only) directs you to step 2; step 2, alternative C (526 and 612) directs you to step 19; and from step 19, you work towards step 26, stopping when you find the problem. You can can end up replacing the battery ECU assembly, a system main relay, the main or no. 2 main battery cable, the battery plug, the no. 2 frame wire, the junction block, or the entire HV battery assembly.

    Be sure to understand the warnings and take care when working around high voltage; it’s quite enough to kill you. If you’re not familiar with megohmmeters, see @ChapmanF's advice in this previous thread; the link to “A Stitch In Time” (PDF), Megger’s guide to such testing, has changed since then.
     
  7. edthefox5

    edthefox5 Senior Member

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    What does this mean:

    "Reseated the connectors in the hybrid battery, the ones I could reach."

    You had the battery out what connector couldn't you reach?

    May be easier and more definitive to swap the battery's between your cars for a test then checking insulation. if 2008 battery is ok in the 2004 no codes then you know its the battery which it most likely is.

    What is the timeline here for this issue? It threw this code out of the blue then you prolonged it? Or it popped up in the middle after you getting into the battery?
     
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  8. zonakicker

    zonakicker New Member

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    Sorry for the delay Ed - in the instructions, it looks like there are connectors on the batter ECU that I didn't get to. I haven't gotten into the car yet, just returned to work from surgery and been wore out. Just keeping the 12v on a trickle charger for now, hope to get back into troubleshooting this next weekend.
     
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  9. zonakicker

    zonakicker New Member

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    Finally getting into this.

    Using the P3009 diagnostic printout. I went to the easy items first at the front of the car, testing the AC Area for insulation (step 18, then 19). Using a borrowed meggar - those tested out fine.

    Then I went back to step 5 HV Battery area. Disconnected the two Battery ECU Connectors and lifted the main battery cables from the system relays. The first time I tested, the positive was showing no good. Then I realized that I left the wire from the positive over to the relay switch, lifted that off and it tested good.

    Based on that, my instructions say to replace the Battery ECU Assy. Looks like I can get those off ebay for $100 or so. I read someplace that the black label is better/newer than the red label? Don't know if that's true or not.

    The real debate is whether to go ahead and replace the HV battery. Ed's idea of swapping the battery from the 2008 prius is a good thought - that would help confirm that the problem is in the HV battery assy someplace.

    The battery is a rebuild from Greentec, warranty expired in 7/2020.
     
  10. zonakicker

    zonakicker New Member

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    Finished swapping the batteries between the '04 and '08 today and the problem moved with the battery. Just ordered an ECU off ebay for $100, will know if that fixes it by Thanksgiving.
     
  11. dolj

    dolj Senior Member

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    I'd take a second look at Elektroingenieur's excellent post:
    Your codes indicate you have a high voltage electrical leak to ground in your hybrid vehicle battery.
     
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