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Replaced 12V battery and still have intermittent Transmission Parking Lock Problem

Discussion in 'Gen 2 Prius Technical Discussion' started by Michael Jabaley, Jun 17, 2012.

  1. Michael Jabaley

    Michael Jabaley michaelj

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    2006 Prius, 114K miles. In the last week started getting the intermittent warning of "There is a problem with the parking transmission lock. Place the car on a flat surface and fully set the parking brake." Car would not start, would only go into neutral. All accessories work fine, seems to be plenty of 12V power. Did a lot of research and determined that the most likely cause was a failing 12V battery. Used the diagnostic mode to check voltages, had 12.1 at "READY", 11.6 under auxiliary loads, and 14.1 with engine on (I did get the car to start eventually but can't figure out how and under what set of circumstances it would start).

    So I ordered a 12V battery and replaced it. After replacing, I still had the Hybrid warning light, but after stopping and starting the car 3 times it went away. Car worked fine for a day but now the intermittent warning has returned. With the warning on, the parking lock seems to be fully engaged (car won't roll even on a slope).

    So now what? Thanks in advance for advice, please reply quickly as I will be monitoring this thread all evening as I watch the US Open.
     
    #1 Michael Jabaley, Jun 17, 2012
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Is it possible that your replacement battery was not fully-charged before you installed it? If so then I suggest you charge the battery overnight and see if there is any change in the symptoms you reported.
     
    #2 Patrick Wong, Jun 17, 2012
  3. Michael Jabaley

    Michael Jabaley michaelj

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    I suppose it's possible, but it did start up after installing it in the car. And I drove it last night and this morning with no problem (a total of about 40 miles), so it would have charged it a little just by doing that. I'm worried that there might be something continuously draining the 12V battery. I'll go out and check the voltages and post the results.
     
    #3 Michael Jabaley, Jun 17, 2012
  4. Michael Jabaley

    Michael Jabaley michaelj

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    Just checked voltages. Got in the car, took it to "READY" and measured 12.4V. Turned on auxiliaries and it went down to 11.9V. Could not get car to start. Tried multiple times, put parking brake on, off, wouldn't start. Just displayed all indications (as normal) but large red triangle on dash and parking lock warning on MFD. After trying several times, then it started. Now voltage went to 14.2V. Drove car around the block a few times, volts fluctuated between 14.3 and 14.1. Large red triangle remained on, and warning bar across top of MFD remained lit.

    Is it maybe the main hybrid battery?
     
    #4 Michael Jabaley, Jun 17, 2012
  5. dhanson865

    dhanson865 Expert and Devil's advocate

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    Nope, just the 12v battery. Did you buy a Toyota battery or a Optima Yellow Top?

    Do you have any add ons like a satellite radio or anything plugged into the cigarette lighter ports?

    Do you drive short to medium distances primarily? Do you run the radio when the car is not in READY mode?
     
    #5 dhanson865, Jun 17, 2012
  6. Michael Jabaley

    Michael Jabaley michaelj

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    Optima Yellow Top, and it measures 12.4 to 12.6 volts through the MFD vehicle signal check screen with no load on it. No addons, nothing plugged in to lights ports. Short to medium distances (max of 20 miles most of the time). Hardly ever run radio without car fully on.

    A new symptom as of last night. The car thinks I have left the keyfob in the slot - when I open the door to get out of the car it alarms as if I'm about to lock the keys in the car, even though they are in my hand. The smart key system is disabled by pushing the switch by my left knee.
     
    #6 Michael Jabaley, Jun 18, 2012
  7. qbee42

    qbee42 My other car is a boat

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    I would try another system reset by disconnecting and reconnecting the 12V battery. Something sounds confused with your electrical system, and a reset will at least bring you back to a known state.

    Tom
     
    #7 qbee42, Jun 18, 2012
  8. Michael Jabaley

    Michael Jabaley michaelj

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    I have disconnected and reconnected several times. Each time the car starts normally with no alarms, but within 5-10 minutes the hybrid warning lights come on (no effect on driving). after shutting down, the next startup is usually blocked due to the transmission parking lock problem.
     
    #8 Michael Jabaley, Jun 19, 2012
  9. Patrick Wong

    Patrick Wong DIY Enthusiast

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    It sounds like it is time for you to visit your local Toyota dealer so that the DTC can be read and a diagnosis provided to you.
     
    #9 Patrick Wong, Jun 19, 2012
  10. Michael Jabaley

    Michael Jabaley michaelj

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    OK - I did that - and the diagnosis is the Shift Control Actuator needs to be replaced - $800 parts, $700 labor for a total of $1500. Does that sound right? I'm not convinced - doesn't explain the keyfob alarm, and it doesn't sound like something that would be intermittent and able to be reset by disconnecting and reconnecting the battery. I'm trying to decide whether or not to shell out $1500 on a car with 114K miles. I plan to retrieve the car from the dealer and continue troubleshooting / drive it until the problem makes itself more clear. Thoughts?
     
    #10 Michael Jabaley, Jun 19, 2012
  11. SageBrush

    SageBrush Senior Member

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    Look at this link from page 4-8 for some info on the actuator. A quick search online found it for sale for about $400. Perhaps autobeyours.com has it for less ?

    Here is a used part for $100 on Ebay. Perhaps Patrick can give an idea how difficult a DIY replacement is.

    Before I bought the part I would look at the harness connection to the actuator for damage, and to check it was seated properly.
     
    #11 SageBrush, Jun 19, 2012
  12. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I haven't had occasion to replace that part but per the Toyota repair manual this looks very simple.

    Get under the car, remove three bolts on the transmission case cover, then three more bolts to remove the shift control actuator. Apply some ATF WS to the O-ring on the new part, install, torque the three bolts at 12 ft.-lb; then install the transmission case cover and torque the transmission case cover bolts at 62 in.-lb.

    I agree that the behavior with regards to the fob is interesting; perhaps the car has more than one issue. I suggest that the fob battery should be replaced, to rule out that as a problem.
     
    #12 Patrick Wong, Jun 19, 2012
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  13. SageBrush

    SageBrush Senior Member

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    12 bolts, 10 minutes of work including time to drink a beer, $700 dealer charges for 'labor'. Sounds about par for the course.
     
    #13 SageBrush, Jun 19, 2012
  14. Michael Jabaley

    Michael Jabaley michaelj

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    OK, in the almost two months since I went to the dealer, the problem has reappeared three times. Each time I was able to reset the car by disconnecting and reconnecting both cables on the battery. The alarm stays locked in until the car has been started three times. My guess is it is some kind of relay that is not operating properly, and when all power is removed it resets. Any other thoughts? Am I destined to live with this for the rest of the car's life?
     
    #14 Michael Jabaley, Aug 14, 2012
  15. mwilson

    mwilson Junior Member

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    Michael,

    Did you ever get this problem solved? I have a 2006 with 101k miles with very a very similar problem. Aux. battery is only 1 year old and the voltages are good.
     
    #15 mwilson, Aug 27, 2013
  16. Britprius

    Britprius Senior Member

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    Have you checked the condition of the negative battery lead where it is fastened to the car body below the rear light. This has been found to be loose or corroded.
    Michael post (4) also suggests a failure in the HV relays or a problem with the DC to DC converter. "The car was made ready and only measured 12.4 volts" this intimates the 12 volt bus was not being raised by the charging system. This in it's self could be discharging the 12 volt battery.

    John (Britprius)
     
    #16 Britprius, Aug 28, 2013
  17. Zedhomme

    Zedhomme Member

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    #17 Zedhomme, Aug 28, 2013
  18. Zedhomme

    Zedhomme Member

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    For the 2006 Prius, I see the part, 35580-47010 for a 2006 Prius online for about $430.
    As Patrick said, the procedure doesn't look too difficult.
    Check the wiring harness as another poster said.
    If it is in securely and doesn't look damaged, you could physically check the actuator rotor first before replacing the actuator.
    To Check the Shift Control Actuator:
    Disconnect the electrical connector to the transmission case cover that connects to the Shift Control Actuator,
    Remove the 3 bolts to remove the transmission case cover,
    Remove the 3 bolts that secure the shift control actuator,
    SLIGHTLY pull the Shift Control Actuator from the hybrid vehicle transaxle.
    Try to turn the Shift Control Actuator.
    If it turns smoothly it is OK.
    There may be an internal actuator abnormality if the actuator doesn't turn smoothly.
    If so, REPLACE the Shift Control Actuator, as earlier poster said applying a small amount of ATF WS to the O-ring.
    If it checks out OK, it may be the Transmission Control ECU under the dash, part number 89535-47020, about $440.
    This Transmission Control ECU controls the Shift Control Actuator and monitors many other functions. It detects DTCs when there are any malfunctions in the system, and informs the driver by illuminating the P position switch indicator and master warning light, and an error message on the multi-display. If it's a problem with the ECU or a system it monitors, first check the harness on that too. It takes an oscilloscope to actually check its functionality, but it's the next thing up the food chain.
    Good luck.
     
    #18 Zedhomme, Aug 28, 2013
  19. Charles Toms

    Charles Toms New Member

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    About the negative battery lead connection to car body. Mine was stripped, loose and became a mess. How about going under a large bolt nearby thats part of a bracket? If not, where? And then, how can I know I have a sufficient grounding?
     
    #19 Charles Toms, Jul 11, 2017
  20. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The negative battery cable needs to be bolted to the body at an unpainted spot.
     
    #20 Patrick Wong, Jul 11, 2017
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