Instrument cluster was already replaced in 2017 on an '06--now intermittently flickering

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Zillennial, Nov 18, 2021.

  1. Zillennial

    Zillennial New Member

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    First off, here's a video of the issue:

    I purchased my '06 Prius back in 2017 and immediately had to fix quite a few of the classic issues (replaced hybrid battery with Green Bean Battery, bought a new combination meter from Module Repair Pro) with the car. After replacing the combo meter, it worked perfectly until last year, 2020, in the fall. I had one day where I went out to the car and the dash did not light up. I drove anyway and the next day it came back on. The same thing happened in May of this year, but not again since, however, it flickers a lot in the video above.

    Some days it does it 9 times in a 6min drive, other days I can drive for 2 hours and it will flicker maybe 2-3 max. Today, it was completely spazzing out for several minutes straight. As you can see in the video, it seems to be resetting? When it flicks, sometimes the gas gauge will drop 2-3 bars at once, and then later it flicks again and the gas gauge gets those bars back. 2 of my tire pressure sensors are already dead, but again, when it flicks back on, that sensor flashes as if the car just "reset" somehow.

    Anyway, pretty soon I am looking at replacing the MFD screen myself, and if I'm already going to be tearing into the dashboard again, I am considering trying to fix this issue. It stressed me the heck out when I had the very classic combination meter back in 2017 after buying the car, but this is not the same classic issue. Does this look like the same combination meter resistor issue or something else? Does this seem like I could tear the dash out, take it out, and visually inspect to check if all soldering joints are in good condition, and that might be the issue?

    Any tips would be appreciated. TIA!
     
  2. L1zz@rd_gr1m@c3

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    In 2017, did you check the farad rating of 'the capacitor' on the combination meter? If you're opening up the dash, you might consider looking into the capacitor everyone talks about as needing to be replaced. The replacement capacitor is rated closer to 200 farad, not the inferior 100-200F of the original faulty capacitor that it came with from the manufacturer. Replacing the capacitor (instead of the combination display entirely) is economical, albeit the project warrants soldering skills and patience to complete. Additionally, in doing this replacement, you won't need to have a new combination meter programmed, which I understand can take weeks to get scheduled and done.

    I'm only spit-balling here. I know how annoying a bad CM is. Good luck.
     
  3. dolj

    dolj Senior Member

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    It appears to be intermittently losing power, so you are right, it is not the classic error.
     
  4. Zillennial

    Zillennial New Member

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    Everything with the CM was done by Module Repair Pro--basically ordered the new part, had a family friend tear into the dash and replace it, and then we mailed the old one back. Unfortunately in all that research back then, had no idea to even look at the capacitor farad rating. I might email the company and ask. My sister solders for her work, as well as I'm a member to a Hackerspace full of solderers, so I do have access to some experts in that area too. I really appreciate the theory! If that is the issue, should I be looking for a 200 farad capacitor or should it be over 200 farad?
     
  5. dolj

    dolj Senior Member

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    Most of the feedback I have seen indicates a capacitor rated at 16 V 220 µF is what was used. The original was 16 V 100 µF so anything with a capacitance higher than should work.
     
  6. Zillennial

    Zillennial New Member

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    Another detail I’ve noticed on my recent longer drives: while driving in cruise control, when the dashboard flicks off, the car briefly accelerates rapidly and then resumes back to the set speed. Another confirmation that it seems like the system is resetting, rather than going dark like the classic signs.

    I reached out to Module Repair Pro, and haven’t heard back yet. I called and am waiting to hopefully hear from a head technician. We’ll see.
     
  7. Zillennial

    Zillennial New Member

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    I have not heard back from MRP so I'll be following up next week with them--but I woke up this morning and my car dash was off the entire day. The trunk still opens (unlike last time). 0 issues turning the vehicle off (unlike last time). The backup camera and reverse beeps do not come on (same as last time).
     
  8. L1zz@rd_gr1m@c3

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    I have never taken a DC (or AC) theory class on this, but I think the 200 will work great to replace the 100 (the faulty one that is the shape and size of a hearing aid battery - not the capacitors that are larger and have a black covering).

    I should say that, after doing this exact repair on the board myself (my FIL, really. He is much better than me on soldering) it fixed the issue I was experiencing (CM display cutting out, etc.)

    Unrelated, based on my observations, there might be other idiosyncratic challenges in the same vein elsewhere on some other electrical system, but that is an unverified/untested theory of mine. That's a subject for another thread.
     
  9. Zillennial

    Zillennial New Member

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    Spoke to someone at MRP and the response was basically "20% of these will fail again, replace the whole unit." Very frustrating. I was (and still am) really hoping that maybe there's a way for me to get in there and work on it, but with the entire dashboard dark and no tracking mileage, and no gas gauge, this repair might have to be expedited. Just thought I'd throw that on here in case someone else is searching the forums for Module Repair Pro, and past the 1yr warranty that's basically the response I got.

    Both reps I've talked to from there also seemed pretty dismissive/short with me, not the best customer service I've had by a long shot.
     
  10. Zillennial

    Zillennial New Member

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    I agree totally on the last point, I think there likely is some other design flaw with these things. Was yours flickering as well, or was it just the classic issue with the dark dash, trunk won't open, etc.? After driving tonight with it like this honestly the worst part is not having the backup camera to double-check behind me before reversing... hoping to open up the dash and attempt a fix sooner rather than later now. It seems like it might have gone dark for good, which makes me worried about doing this fix and it still not working.
     
  11. dolj

    dolj Senior Member

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    One repairer, @Texas Hybrid Batteries, changes at least 3 capacitors, so maybe one of those others in yours needs doing. That is assuming MRP did not do all three.

    THB gives a lifetime warranty on their repairs, so they are pretty confident in what they do. I'd be pretty interested to hear if THB has a 20% failure rate. I suspect not.

    Other than that thought, I've got nothing else.
     
  12. Another

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    This regrettably is not uncommon in manufacturing. Cheap Chinese capacitors are routinely found to fail in many electronic devices. I’ve seen many an otherwise good laptop computer having a failed capacitor in a very difficult to access location on the motherboard rendering the device useless after five years or so. Toshiba used to have this issue on their consumer lever laptops. Also Bose routinely had this issue on their expensive Apple sound docks. The manufacturers make a few million dollars in bottom line profits and get to sell a new device earlier than otherwise would be the case. A win-win for them, a lose-lose for the consumer and the landfill.
    Kudos to people like THB who repair the devices and are proactive enough to change all of the caps at the first failure to avoid redoing the work later.
     
  13. Texas Hybrid Batteries

    Texas Hybrid Batteries Senior Member

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    The symptoms that the op is experiencing isn't something we've seen before. We have seen issues where the the fluorescent display on the combination meter burns out or flickers but the electronics (power supply, processors, ect.) are still running fine. In this case it's clear that the entire combination meter is powering off and back on again. That could be an electrical problem in the car (broken wire, bad relay, loose connection) but that type of stuff is very unusual. Since the combination meter is the one thing that has been worked on before that's probably where I would start.

    Now about the combination meter repairs that MRP does, I'm very familiar with their work because we've had quite a few returned as cores from our customers. I'm not surprised that they have a 20% failure rate and I would bet that it's much higher for the people who have those meters 3-5 years down the road. Their approach to fixing this problem is completely wrong and I'll try to explain why.

    The 100uF capacitor that everybody talks about upgrading to a 220uF is connected to the output of the voltage regulator on the circuit board. The voltage regulators job is to reduce the 12-14 volts from the car down to a steady 5 volts for the processors and other electronics in the combination meter. The voltage regulator also has a built in protection circuit that automatically terminates output if it doesn't see 5 volts going out within 5 milliseconds (thats 1/200th of a second, really fast!). As the original 100uF capacitors age and build up resistance it causes a slight delay that can exceed the 5 ms limit and cause the regulator to shut itself off. This is all to protect the electronics on the board and make sure they are receiving the correct power. The result of all of this is a system which is barely operating within its own safe limits and any change in ambient temperature or supply power (from the 12 volt battery) could cause it to fail to power on.

    The correct way to fix this problem is to replace the failing capacitors so that the built in protections aren't being triggered. Even if you went back with exact same capacitors that were originally on the board it would fix the problem for another 10+ years. By upgrading to the larger capacitor it solves the original flawed design and ensures that the problem never comes back. This is what we do.

    What MRP does is adds a small resistor across the voltage regulator which slows down the safety timer and "tricks" the output protection into waiting 10-15 ms before shutting off instead of the 5 ms that was originally designed. This allows more time for the output to stabilize and forces the circuit to work even with the failing capacitors. Common sense should tell you that this isn't going to last because over time that capacitor will continue to degrade until it reaches the new time limit that you've created and start having the exact same problem again. This is a perfect example of a band aid repair, instead of fixing the actual problem they found a way to make it work with the failing parts (for a while at least).

    We have repaired around 6,000 Gen2 Prius combo meters in the last 5 years and we've had less than a dozen failures from those. Out of those few issues none were related to the power supply circuit (capacitors and regulators). They had other issues that probably resulted from handling during removal, shipping, or installation. You have to figure that every meter goes from (1) removal from a car, (2) into a box and shipped as a core return from all over the country, (3) processed thru our shop for repair, cleaning, testing, and programming, (4) shipped out again, (5) and finally installed in another car by a shop or Prius owner. We bench test every meter and road test them in one of our shop cars before they go out so it's highly unlikely that a malfunctioning meter would make it to one of our customers but if it did you can bet we would take care of it immediately.

    I get frustrated with companies who sell junk and even admit that 20% of their parts will fail again within a few years. If that's the case you have to stop what you're doing and find a better way. Unfortunitly most companies care more about profit than supplying a quality product.

    Matt

    To the op - Sorry I couldn't provide you with better advice other than replace the meter and see if that fixes it. If you'd like to go that route please feel free to pm, email, or call me with any questions. After your experience with MRP and the lack of customer service they offered you I would personally handle anything you needed and ensure that your experience with our company was a great one.
     
    #13 Texas Hybrid Batteries, Dec 13, 2021
    Last edited: Dec 13, 2021
    Zillennial, nancytheprius and dolj like this.
  14. Zillennial

    Zillennial New Member

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    Matt!

    Thank you so much for the thorough and very educational response, I really appreciate it. I had it on my to-do list to send you guys an email to see what you thought so thank you for reaching me before I could make time to reach you! Now that my dash is completely dark (only the check-engine light flashes once when powering the car on, MFD does not display MPG info, turn signal indicators are still functional, no issues turning the car off, the trunk still opens), your recommendation is still to try replacing the combo meter and see if that remedies the issue? I am concerned it's some other wiring in the dash but I understand there's no real way for me to diagnose that without opening up the dash to investigate it. I'm definitely willing to move forward with getting the replacement from you guys as a first step, and hopefully that will do the trick.

    And for the record, I have RSI in my hands that makes it impossible for me to unplug the 12V battery as a temporary fix, but I could easily get help if that would provide anything for troubleshooting it. The dash has now become completely dark for 5 days and makes me think it finally went completely fully kaput, a little over a year since it started acting up.
     
  15. Zillennial

    Zillennial New Member

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    As a hopefully final update: we went with the new THB combo meter and my dashboard is properly lit up again! As a separate issue, there is some damage on the blue ribbons inside the unit, which seems to be the cause of an infrequent issue where I am just driving and some warning lights randomly pop on, but remain off once I shut the car off and then turn it back on again. Unrelated, and totally bearable as an issue. Just happy to see my speed and gas gauge and odometer again!
     
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