MPG display not getting information

Discussion in 'Generation 1 Prius Discussion' started by primuspaul, Jul 28, 2014.

  1. primuspaul

    primuspaul Member

    Joined:
    Mar 23, 2014
    235
    11
    0
    Location:
    NYC Area
    Vehicle:
    2002 Prius
    Model:
    I
    If I open the driver door, I get the red door open symbol on the dash. Goes away when I close the door.
     
  2. Wisco

    Wisco Member

    Joined:
    Sep 26, 2013
    115
    20
    0
    Vehicle:
    2002 Prius
    Model:
    N/A
    Like I said, I have no personal experience with this. These are pics of the diagnostic procedure if you have DTC 93 (gateway ECU communication stop). Since you haven't confirmed you have any DTCs, this may be the wrong angle.

    [​IMG]

    [​IMG]
     
  3. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    8,268
    5,917
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    At the diagnostic ("DLC3") connector above the driver's left knee, one of the terminals is called CG (chassis ground, terminal 4) and one is called Tc (I've never known why, terminal 13). When you jumper those two with a wire, most of the car's ECUs go into a code-output mode. Each ECU has its own light on the dash that it's responsible for blinking, and you count blinks to read two-digit codes. (Also, the MFD goes into the same diagnostic screen you've already seen, but in Japanese.)

    So, the engine control module blinks its codes on the check-engine light, the brake ECU blinks the ABS light, the airbag ECU blinks the airbag light, and the body ECU blinks the door-ajar light. Nine blinks, a short pause, then three blinks would be your code 93. (In case you're wondering, the HV and battery ECUs don't have lights to blink, so you can't get their codes without a reader of some sort, and the steering ECU puts its blink signal on a wire that goes all the way to the back of the combination meter in the dash but there's no light connected to it.)

    The body ECU can only blink the door-ajar light if it is able to communicate with the combination meter. If it finds that it can't, it blinks codes on the dome light instead.

    -Chap
     
  4. primuspaul

    primuspaul Member

    Joined:
    Mar 23, 2014
    235
    11
    0
    Location:
    NYC Area
    Vehicle:
    2002 Prius
    Model:
    I
    I am using a "CAN Device using a Silicon Labs part from Texas" that a member on here sent me along with PriiDash 3 MFD. I don't know if it can connect or not, but at least in DTC mode it shows no DTCs. I suspect it simply cannot connect to the car. My other ELM can connect, but cannot read Prius codes, like the one time I had a red triangle and it showed no codes (but could clear them).

    Could you clarify what you mean? You are talking about the OBD-2 connector below the steering wheel? I need to put a wire between some of the connectors? Do I need to have the car in accessory mode, ON mode, or engine started?

    I think another issue is that I did not spot the problem due to a DTC, but rather due to a symptom. Is it possible the G/W ECU is only damaged or disconnected where it connects to the MFD? If so that would explain the lack of other symptoms.
     
    #24 primuspaul, Aug 3, 2014
    Last edited: Aug 3, 2014
  5. primuspaul

    primuspaul Member

    Joined:
    Mar 23, 2014
    235
    11
    0
    Location:
    NYC Area
    Vehicle:
    2002 Prius
    Model:
    I
    Also, I saw this post on a Yahoo group:

    Toyota Prius (2002 vs 1) replaced accessory battery and now shuts off after starting?

    Is this going to happen again if I disconnect the 12V battery?
     
  6. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    8,268
    5,917
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Yes, a jumper wire between pins 4 and 13. You might feel more comfortable poking the jumper in while the key is OFF, then turning it ON. (No need for READY, just ON.) You'll see the MFD go into Japanese-diagnostics mode and the lights on the dash begin blinking. Then just count blinks.

    Any light that is just blinking a steady quick on/off means that ECU doesn't have any codes for you.

    Our car model does have a strange "startless start syndrome" that occasionally shows up, usually after you've done something, such as having the 12 V battery out. Others have reported it, and it has happened to me one time. If it happens to you, you can tell because you turn the key, the engine spins up for several seconds, then sputters down without starting. When it happened to me I made enough attempts, while testing different things, to be convinced it is purely a soft condition in the ECM and does not (by itself) indicate any mechanical problem with the engine that needs to be fixed. I did not have enough chances to really pin down exactly what ECM outputs weren't right (because crank attempts come out of the HV battery, and when it got below 30% I called off the experiment).

    At that point, I just disconnected and reconnected the 12 V battery one more time to give all the ECUs another reboot, and it started right up on the next attempt.

    There are a lot of other threads discussing this, and some of them have other things they say you must do, like clean the intake manifold, shift into neutral, or sing "Home on the Range" backwards. Some of them come with elaborate explanations of why it is happening. Maybe some of them are right. They're usually stated as something the poster just knows, instead of with the observations and reasoning that led to them thinking that, and sometimes I'm not sure whether they're really any closer to figuring it out than I am. On the other hand, I definitely haven't figured it all out myself, so they could be.

    The bottom line seems to be that it may, on rare occasions, happen (I've had my 12 V battery disconnected a bunch of times, and have still only seen this syndrome once), and if it happens to happen to you, don't panic, don't go tearing your engine apart - but also don't keep making the same unsuccessful attempt over and over, without taking some action in between, so you don't run out of HV battery while trying.

    -Chap
     
  7. primuspaul

    primuspaul Member

    Joined:
    Mar 23, 2014
    235
    11
    0
    Location:
    NYC Area
    Vehicle:
    2002 Prius
    Model:
    I
    Is there a diagram of the specific 2002 Prius OBD-2 plug so I can clearly see where those two pins are? I don't want to short anything out.

    Also, given these syndromes, is it safer to unplug the battery and risk the syndrome, or just replace the G/W ECU with 12V connected?
     
  8. primuspaul

    primuspaul Member

    Joined:
    Mar 23, 2014
    235
    11
    0
    Location:
    NYC Area
    Vehicle:
    2002 Prius
    Model:
    I
    Well, I put the ECU in and it did fix the problem. Now I get battery info and temperature. Unfortunately, I completely broke the dashboard. It basically fell apart as I took it out! I tried to start the car and drive it a bit, no triangles and no start-stop syndrome this time.

    Any help regarding getting a replacement would be appreciated. I suppose a junkyard is the place to go? What would they charge for the entire thing minus the MFD and ECU? What is it called?
     
  9. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    8,268
    5,917
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV


    You're looking for the instrument cluster finish panel, center.

    I don't know what one would cost at a salvage yard, but what happened to yours was years of sunlight baking the plasticizers out of it so it was extremely brittle, and that would be a risk with any non-new replacement.

    I still think I might have been able to get mine out without busting it if I hadn't overlooked the nuts under the MFD. That's my story, anyway, and I'll never know if I really could have. Anyway, my new one looks nice and is probably a lot less likely to crumble if I ever have to take it out again.

    Glad the replacement gateway fixed your functional problem.

    -Chap
     
  10. primuspaul

    primuspaul Member

    Joined:
    Mar 23, 2014
    235
    11
    0
    Location:
    NYC Area
    Vehicle:
    2002 Prius
    Model:
    I
    Does the instrument cluster you posted include the moving vents (both vertical and horizontal), the clock and the radio control buttons?
     
  11. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    8,268
    5,917
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    I believe it does include the air vents, yes, because I ended up with spares.

    The clock and buttons you transfer over from the old one with everything else. It's a bit tedious.

    -Chap
     
  12. primuspaul

    primuspaul Member

    Joined:
    Mar 23, 2014
    235
    11
    0
    Location:
    NYC Area
    Vehicle:
    2002 Prius
    Model:
    I
    Out of curiosity, do they sell those buttons and clock?

    Also, another interesting thing to note:

    A symptom I had with the MFD is that it would always go dark when headlights were turned on. The main instrument panel (with speed) still responded to dimmer settings, but MFD was as if it was always set to dim when headlights turned on. After replacing GW ECU, MFD again worked according to dimmer settings.
     
  13. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    8,268
    5,917
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    The clock and buttons are shown in the parts catalogs, with part numbers. I guess that doesn't always guarantee every such part is in distributor stock or even still in production, but those are things you only find out when placing an order really. Nothing I see says they aren't available. Are your clock and buttons funky?

    I'm pretty sure my MFD only has two brightness modes, the day mode, and the darker night mode it goes into when the headlights are on. (I think you can also hit the Display button and find a menu to change between the two modes manually.) I don't think my night mode follows the settings of the dash dimmer control, it's just a fixed level that's not as bright as daytime. Are you saying yours actually follows the dimmer control now?

    Reminds me of the old "doc, after the procedure, will I be able to play the violin?" joke....

    -Chap
     
  14. primuspaul

    primuspaul Member

    Joined:
    Mar 23, 2014
    235
    11
    0
    Location:
    NYC Area
    Vehicle:
    2002 Prius
    Model:
    I
    The dimmer near the driver door controls whether or not the MFD goes into dark mode when headlights are turned off. If GW ECU is broken, it always goes into dark mode with headlights on. If ECU is working, it depends on position of dimmer.
     
Loading...