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No regen brake! DTC C1203 C1245 C1253 MYSTERY!

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by bequa, Sep 9, 2014.

  1. bequa

    bequa Junior Member

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    Hello to all,

    My 2004 Prius has 100k miles, serviced well, changed oil every 3500 miles, feeding with unleaded 95 octane fuel, never had any problem despite the fact that it had been bought wrecked and was rebuilt well.

    One day to my way to work I opened door and heard a beep for 2 seconds, was strange, but I said, well its OK, because car ran well that day.

    Another day when I opened door the beep was there again for 2 seconds, but I decided to go on as usual, because there was no lights blinking on the dash, nor any noticeable issue, after 2 minutes as I was gliding downhill I heard this beep again, but it was continuous and lights got on !!!
    Red BRAKE (parking brake light), Yellow (!) and ABS were lit and stayed on.

    I pulled over, could not find anything unusual, checked fuses I saw blown lower ABS-2 FUSE under the transparent cover under the hood fuse box.

    I was told Brake Actuator Assy was gone.. I bought one used from junkyard, replaced it, fixed the FUSE.
    But error lights did not go away!

    I confirm that we did:
    Bleed air removing brake relays and shorting pins on DLC, all went well, no more air in the system.
    Tried initialization/calibration of linear solenoid valve, lights go blinking but in the middle they stop blinking and make beep, so it was not completed successfully.

    Here are the error codes what were obtained from DLC:
    C1203 ECM problem
    C1345 Linear solenoid needs calibration/init

    and after 1/4 mile test drive C1253 hydro-booster relay problem also appeared.

    I have read many threads on this forum but my car still needs help. There is no regen brake, manual brakes are strange and lights are still on.

    What would you suggest ?

    Please help solving this mystery!

    Big thank you in advance !
     
    #1 bequa, Sep 9, 2014
    Last edited: Sep 9, 2014
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    DTC C1203 means the skid control ECU needs to be replaced.
    DTC C1253 points to a problem with either the ABS MTR or ABS MTR2 relays, or the brake actuator, or the associated wiring harness
    DTC C1345 means the linear solenoid needs calibration as you said.

    I would start by finding and testing the MTR and MTR2 relays. Remove each relay, one at a time. Use a digital ohmmeter to find the relay coil terminals. Apply 12VDC to the coil terminals and measure resistance of the switched terminals. After accounting for resistance of the ohmmeter test leads, the measurement should be 0.5 ohms or less. Replace the relay if you get a poor result.

    If the relays are good, then you may need to purchase a used skid control ECU and replace it. This is not easy because you have to remove most of the dashboard, airbags and steering column for access to that ECU hiding near the steering column.

    See techinfo.toyota.com for repair manual info which you will need to go that far.

    Regarding fuel octane, the Prius is designed for 87 octane fuel. Unless you have a drivability issue from using that fuel grade, there is no need to pay more for higher octane fuel.
     
    bequa likes this.
  3. bequa

    bequa Junior Member

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    Hello Patrick,

    Its nice to have you here, you are always helpful!

    Yes I have checked those relays, even have replaced them from the friends Prius which has zero issue. Problem remains.

    My skid ecu part no is: 89540-47060
    It was really hard to remove upper bolt holding it,
    I have been to junkyard locally, have not found same part no.
    But anyway I have tried with 89540-47080 and 89540-47100.
    No luck with them .. Do you think part number should be exact ?
    I think those part numbers just points updated version of hardware/software of ecu itself, or does not it?

    I'm just out of ideas!
     
  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    When you say "no luck", does that mean you have tried to install 47080 or 47100 and the warning lights remain on? Or does that mean you cannot locate a used unit?

    Have you tried autobeyours.com or eBay as used parts sources?

    I don't know if you can use a higher part number suffix or not. But if you really can't find 47060 and you haven't yet tried 47080, that might be worthwhile assuming the used part doesn't cost much.
     
    #4 Patrick Wong, Sep 9, 2014
    Last edited: Sep 9, 2014
  5. bequa

    bequa Junior Member

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    Yes I have installed them (80 and 100) but lights still were on, even after I tried to initialize but initialization process was not complete, I'm hearing brake noises while this process and then it stops after 5 seconds or so . It should go on blinking and when it completes lights should blink in 0.25 sec intervals.

    I tried higher suffix part no. because I have read on this forum that Toyota quoted higher suffix part number 89540-47130 as 89540-47100 replacement. Source: Skid Control ECU replacement part help | PriusChat

    I'm not in US and buying part online takes 2 weeks to deliver to me and that's why I have not ordered skid ecu with exact part no. on ebay.

    I think I'm going to check wiring as shown in repair manual BC-118 and BC-119 but it is very unlikely to be the problem.

    Any more ideas?
     
    #5 bequa, Sep 10, 2014
    Last edited: Sep 10, 2014
  6. bequa

    bequa Junior Member

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    @Patrick Wong

    Problem is solved, lights are gone !!!

    Problem was in wiring, actually lower ABS RELAY Ground was not connecting to ABS Actuator assy Ground,
    What caused it? Here's what:

    When bleeding air or changing brake fluid, its mandatory to remove 2 ABS relays, they sit very tight, removing them several times loosened one of the terminals,

    End of story
     
    nh7o and Patrick Wong like this.
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Glad you found the wiring problem.

    To summarize, your car had two problems: a failed brake actuator, and an ABS relay with a loose terminal. Is that correct?

    Which skid control ECU ended up being installed in the car, and can you sell the other ECUs to other owners in your country, or perhaps Russian or other European owners?
     
  8. bequa

    bequa Junior Member

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    Yes seems that there was only 1 problem, Brake actuator,

    And wiring was damaged unintentionally by us removing relays several times, so everyone who removes them, keep in mind, be very gentle.

    Installed Skid ecu is original, 89540-47060, there is no need to change it, the other two ecus will be returned, its no problem in our area.
     
  9. bisco

    bisco cookie crumbler

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    congrats!(y)
     
  10. whburling

    whburling Junior Member

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    Hi!
    I greatly appreciated the dialog between all the participants.

    I need to better understand what is meant by "2 ABS relays, they sit very tight, removing them several times loosened one of the terminals"

    I understand what you mean by "sit very tight" but i don't understand how I can see or know the terminals are loosened. Do you remove the entire terminal block and look at the backside? if so, are not the female recepticles on the male ABS relays held into slots by "spring" action of the recepticles? so how you one do anything about the loose terminals?

    please help me understand as I suspect I have a similar situation.

    thank you
    bil
     
  11. whburling

    whburling Junior Member

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