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Help with 2 digit flashing light codes from bridging OBD2 pins 4 & 13

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by theorist, Jul 30, 2019.

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  1. theorist

    theorist Member

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    Can someone help decode the following codes?

    These were obtained by bridging OBD2 pins 4 and 13, turning the Prius, then counting the flashing sequence of each dash warning light.

    Here are the codes I obtained:
    (!): 36 57 64 (!) meaning the yellow exclamation point with a yellow circle around it
    ABS: 35 36 42
    VSC: 43 45
    ​
    Thank you!
     
    #1 theorist, Jul 30, 2019
  2. theorist

    theorist Member

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    For some background on this car, this problem:
    2006 Prius, 168,000 miles, original owner
    Weather has been unusually hot.
    Car has had P0420 (catalytic converter inefficiency) and P1121 (coolant control valve) OBD2 codes.

    This morning at startup the brake, (!) yellow exclamation point in a circle (!), ABS, and VSC lights all came on and remained illuminated. (By the brake light I mean the dashboard warning light that reminds one that the parking brake is engaged or the brake fluid is low.)

    The family member who drives the car daily said she hadn't seen these lights before but is known to overlook dash lights.

    In the hot weather, the hybrid traction battery is more easily depleted, as we've observed in other recent summers.

    I believe the inverter coolant pump was replaced years ago under warranty.

    Reading about how the Toyota scan tool is needed to bleed the brakes after replacing the brake actuator, it reminds me that I've never bled its brakes =(. It still has its I drove the car slowly and carefully after seeing the brake, (!), ABS, and VSC lights. The car made no beeps and drove a short trip without incident. I read the above codes and am hesitant to drive the Prius without fixing or at least determining the cause of the problems.

    I bridged OBD2 pins 4 and 13 and described on priuschat to obtain the 2 digit flash codes I'm asking about. The lights did not go away after bridging the pins to ground TC.​
     
    #2 theorist, Jul 30, 2019
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    ((!)) 57 and 64 is pointing to a problem with the brake actuator.
    ABS 35 and 36 indicate a problem with the left front and right front wheel speed sensors.

    The car is unsafe to drive in this condition as the brake actuator has lost its ability to maintain hydraulic line pressure for the braking system.
     
    #3 Patrick Wong, Jul 30, 2019
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  4. theorist

    theorist Member

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    Thank you Patrick!

    Does anyone know what the other codes mean individually?

    (!): 36 (!) meaning the yellow exclamation point with a yellow circle around it
    ABS: 42
    VSC: 43 45

    This Prius's daily driver says the brake, (!), ABS, and VSC lights came on simultaneously when I got in as a passenger. (I can't be certain as I've been riding my Kawasaki 250 for 70 to 77 mpg and hadn't driven it in the last month.) Would any of these individual codes have caused a dash warning light to illuminate? It seems unlikely that two ABS sensors, the brake actuator and more would have independently failed within a couple days or even a month. Is it possible that a failure of a single computer control unit for the ABS, TC, and VSC could cause all of these codes?
     
    #4 theorist, Aug 1, 2019
  5. ChapmanF

    ChapmanF Senior Member

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    I am not finding those in a 2006 Repair Manual, at least not in that code-to-light association.

    Patrick has pointed out before that the manuals don't seem to be as complete or well-proofread with respect to the two-digit blink codes as they are for the five-character full DTCs. I find the blink codes useful enough often enough that I will check them if a problem comes up and I don't have a DTC reader handy. But sometimes, a few of the codes will just sort of lead to a mystery that doesn't get solved without hooking up a reader and getting the full DTC.

    If people would report back the actual DTCs after reading those, we might over time piece together more of the DTC-to-two-digit code correspondence ourselves ... but that seems to happen rarely.
     
    #5 ChapmanF, Aug 1, 2019
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  6. theorist

    theorist Member

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    Thank you.

    I reset the codes by pumping the brake repeatedly with a paperclip connecting pins 4 and 13 on the OBD2 port.

    The brake, (!), ABS, and VSC dash lights turned off for a while. Intentionally engaging the ABS with a sudden hard stop demonstrated that the ABS was now working. Eventually the lights returned. Connecting pins 4 and 13 yielded a reduced set of the 2 digit flash codes.

    Here are the codes that returned relatively quickly:
    (!): 36, 57 64 (!) meaning the yellow exclamation point with a yellow circle around it
    ABS: 35 36 42
    VSC: 43 45​

    Anyone care to share their insight into what these returning codes indicate?
     
    #6 theorist, Aug 3, 2019
  7. theorist

    theorist Member

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    I'm hoping it's not the brake actuator. If so, I wish I replaced the car earlier. I thought the traction battery would be the potential expensive repair, not a brake actuator or CARB catalytic converter.

    What's a cheap and easy way to get the full ABS DTC's?
     
    #7 theorist, Aug 3, 2019
  8. ChapmanF

    ChapmanF Senior Member

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    The ABS 42 and VSC 45 are two of the same codes I couldn't find in the manual yesterday.

    64 on the ECB light corresponds to C1343. It detects that "hydraulic pressure control on RR wheel has deteriorated."

    In essence, the brake controller is choosing a target pressure for the RR wheel and trying to reach and hold steady at that pressure, but seeing from the pressure sensor on the same hydraulic line that it's doing a lousy job, either undershooting or overshooting the target pressure, or hunting unsteadily around it.

    If you read the codes with Techstream, a C1343 can have five different three-digit INF codes that further describe the problem. Two of them (571 and 572) don't add very much INF, just that it's a deterioration of control, maybe from fluid leakage or a faulty actuator.

    Two of them, 574 and 575, further pin down that if it's an actuator problem, it might be leakage in the pressure decrease valve for that wheel (SLRRR), so the controller is trying to hold a target pressure but keeps having to add more because the pressure keeps dropping.

    The remaining one, 573, would mean the problem could be leakage in the pressure increase valve (SLARR), so the controller is trying to hold target pressure but keeps having to release more because the real pressure keeps rising.

    All of the subcases could be caused by fluid leakage or a faulty actuator (that's where these various valves are). The 573, 574, 575 could also be caused by a warped rotor on that wheel, which the ECB will see as pressure variation. (You might expect that you would also feel a warped rotor as pedal pulsation, but the ECB effectively masks that, and has to be disabled before you could feel it.)

    There are about eight pages in the manual on how to tease apart the various possibilities.

    As for an easy way to get the codes and other info, a lot of PC members end up using Techstream and a laptop one way or another, if they plan to work on the car more than once in a blue moon.
     
    #8 ChapmanF, Aug 3, 2019
  9. theorist

    theorist Member

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    Thank you. The lights haven't returned since I reset it. I'll try to get back to it soon.

    That rear right wheel brake had other problems a few months ago. After my mother took it to a local garage which replaced the rear brakes, I found that the rear right parking brake was barely engaging when I did the next seasonal tire change. After removing the brake drum I found that the adjustment wheel was so loose that it would not self adjust. I tightened this and it seemed all was well. I should reinspect that brake.

    I don't know why it threw all the other codes, including ABS codes 45 and 46 for both front wheel sensors. Perhaps it was because the 12V battery ran a little low when I used this Prius to recharge the battery of a Mazda3 that has been undriveable and sitting while I've been relying on my motorcycle (70-77 mpg on an old 250cc Kawasaki I bought for $400 that will run 0-60mph in under 7 seconds. Far less safe that a car but more economical and far more fun :)
     
    #9 theorist, Aug 7, 2019
  10. ChapmanF

    ChapmanF Senior Member

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    A followup on this thread concerning the few 'mystery' blink codes that can't be found in some editions of the Gen 2 manual (36 on ECB, 42 on ABS, 43 or 45 on VSC): more here.
     
    #10 ChapmanF, Aug 25, 2021
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