1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Another C1344 question

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Frank06, Mar 6, 2016.

  1. Frank06

    Frank06 Junior Member

    Joined:
    Sep 5, 2011
    51
    5
    0
    Location:
    Maine
    Vehicle:
    2006 Prius
    Model:
    N/A
    Hi Everyone:

    My daughter drives our old 2006 and had the oil changed some time ago at a Walmart close to where she lives in North Carolina. Anyway, when she picked the car up she said that they were futzing with it and told her they didn't know how to turn off the "maintenance required" light. She called me and I told her. I just found out NOW (5K miles and 6 months later - she's here for a visit) that a bunch of other lights also came on when they did the oil change. VSC, ABS, etc. My scanner shows C1344 "malfunction in hydraulic system (rear left)" which seems consistent with what I've read. I have no idea how an oil change could have anything to do with this but maybe they were screwing around with stuff they knew nothing about.

    I got the brake drum off and everything looks fine, other than the brakes not activating of course. I tried to reset the code with my scanner but it didn't seem to work. I have two questions:

    Is there another way to try to reset the code ex. disconnect the aux. battery?

    Can someone explain where the ABS brake actuator is and what its function is? Is this a DIY job or does it require special tools?

    Many thanks.
     
    #1 Frank06, Mar 6, 2016
    Last edited: Mar 6, 2016
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,198
    6,461
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    DTC C1344 is logged by the skid control ECU. One way to clear the DTC is by using a jumper between pins 4 and 13 of the OBD-II connector and there are several posts about exactly how to do that. However your car likely has a real problem that will not go away. If your scanner could not clear the DTC then the root cause of the problem most likely is current.

    If you don't see any leaking at the rear left brake wheel cylinder then you would need to replace the brake actuator. That potentially can be a DIY job if you get Mini VCI and subscribe to techinfo.toyota.com to obtain factory repair manual info. You would have to remove the sheet metal tray that runs across the back of the engine compartment. That tray houses the windshield wiper motor. Once the tray is removed then you will be able to access the brake actuator. Obviously you need appropriate tools to remove and replace the brake actuator, such as the correct wrench to remove the several brake lines connected to the actuator, without causing damage to those lines or fittings.

    The brake actuator provides hydraulic force to the front brake calipers and rear brake wheel cylinders. It is needed because of the hybrid drivetrain, since the engine is not running part of the time. The brake system, not being able to rely upon the continued presence of engine vacuum to power a traditional power brake booster, needs an alternate design. That design features the brake actuator which is controlled by the skid control ECU to route an appropriate amount of hydraulic pressure to the front and rear brakes after the hybrid vehicle ECU has determined what portion of the braking will be achieved by regen action taken by the motor generators within the transaxle, vs. friction braking needed at the four wheels.

    Hopefully you can appreciate that the overall braking system is highly complex. Nevertheless, it is possible for you to replace the brake actuator if you do your homework and obtain Mini VCI and the proper hand tools for the job. Good luck.
     
  3. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,571
    48,862
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    how many miles on her?
     
  4. Frank06

    Frank06 Junior Member

    Joined:
    Sep 5, 2011
    51
    5
    0
    Location:
    Maine
    Vehicle:
    2006 Prius
    Model:
    N/A
    208K.

    Thank you Patrick for a clear, concise explanation.
     
    bisco likes this.
  5. Frank06

    Frank06 Junior Member

    Joined:
    Sep 5, 2011
    51
    5
    0
    Location:
    Maine
    Vehicle:
    2006 Prius
    Model:
    N/A
    Update: the code is gone and warning lights are off. Possible reasons:

    - there was something hanging loose underneath the rear of the car; it's approximately 1/2" X 1/2" X 4" long, black with two wires (blue and red?) leading into it. It was attached with two small screws at each end but they rusted away. The blue wire was broken: I crimped it back together with heat-shrink, tape, etc. and cable-tied it back up underneath. Some sort of sensor or resistor or ?

    - I might not have been properly clearing the codes with my scanner: it's been awhile since I used it but after effecting the above repair and using the scanner, the codes are gone.

    Now to drive the thing for awhile and see what happens. Maybe I got lucky!