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Code U0155 in 2010 Toyota Prius

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by goshdonit, Jun 27, 2022.

  1. goshdonit

    goshdonit New Member

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    Hi there, it’s my first time posting here so I hope I do this correctly. Please let me know if additional info is required to help with determining the best way to fix.

    I have driven a 2010 Prius (Trim V) for several years, which was handed down from my grandmother to me. I just got a BlueDriver OBD2 reader and plugged it in, and code U0155 came up: “Lost Communication With Instrument Panel Cluster (IPC) Control Module.”

    I am surprised at this because I haven’t noticed any issues with my instrument panel at all. They all light up fine when I turn on the car and turn off a few seconds later like they are supposed to. I have noticed now that the battery and check engine light both seem to turn off faster than the other lights, but I don’t think that’s new or indicative of any problems.

    BlueDriver’s app states that this is a common problem and recommends replacing the IPC control module. After perusing some threads on here a bit (particularly this one), I also am seeing that the problem could be related to the 12v battery. Back in April, I was advised to buy a new 12-volt battery, so I did and installed it myself. I’m not particularly knowledgeable about cars but the repair seemed easy enough, and I haven’t noticed any problems at all with the new battery either.

    I don’t want to risk missing some more serious problems with the car because of a malfunctioning IPC. Does anyone have thoughts as to what might have tripped this code? Should I just take it into a shop and have them look around? I’m not sure how urgent or expensive of a repair the IPC control replacement would be. Is it something I could DIY?
     

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  2. JC91006

    JC91006 Senior Member

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    So is there something wrong with your car for you to plug something in to read codes?
     
  3. goshdonit

    goshdonit New Member

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    I have noticed the engine sounds like it’s running a bit louder than it used to and seemed to struggle a bit to accelerate/decelerate when I depressed the gas or brake pedal.

    So I got the OBD reader for that reason, though I will admit that this noise I’m hearing could be nothing more than my anxiety around further repairs on this car, since in the past eight months alone, I’ve spent roughly $7000 in non-routine repairs: replacing the digitizer on the head unit, a new windshield, replacing four new tires, repairs to frame damage around the radiator body, and a head gasket replacement.

    The digitizer replacement is the most recent of those repairs, and I haven’t finished reinstalling it yet, so the head unit screen is currently not working. Maybe that triggered it? I’m not sure if that is considered part of the control panel or if it has any control over the panel’s functions.
     
    #3 goshdonit, Jun 28, 2022
    Last edited: Jun 28, 2022
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  4. JC91006

    JC91006 Senior Member

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    I have the exact model car you have a 2010 V, I would have to think really hard before spending $7000 on the car. Although the $7000 wasn't all spent on a single repair, it's still a big chunk of money on a 2010 that will need more money for other needed repairs later.

    I would think the acceleration issues you're having is because your HV battery state of charge is low when you're noticing this issue. When the battery is full, your acceleration shouldn't be affected. If the HV battery is original, it may need to be reconditioned or prepare for a new one when it fails.

    Is the digitizer is screen or the AC controls? I don't know the official term for what you're replacing. Did you buy used parts off another car?

    I know I would have anxiety after spending that much money, but on this 2010, you might just be faced with a little more anxiety when the HV battery and Brake Booster/Accumulator needs replacement. Both those are high cost items when they fail.

    It seems like your car is really not experiencing any real issues at the moment. You may just want to drive it.
     
  5. bisco

    bisco cookie crumbler

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    and clean the egr circuit before the head gasket blows
     
  6. goshdonit

    goshdonit New Member

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    I definitely hesitated before spending that much money and have looked into replacing the vehicle. Unfortunately, the first repair I had to do was also the most expensive one, the head gasket repair for $4500. After spending that much money on the car last November, it’s felt like a waste to get rid od the car now.

    I was warned by the dealership last year that the HV battery may need replacement eventually (in the next year or two) so that’s at least not news. I will look into the reconditioning you mentioned.

    The digitizer is just the glass touch screen on the head unit, which controls audio and the map display. I got it from a reputable seller on eBay. I would provide the link but apparently my account is still too new to post the links haha.

    my chief concern is that if the IPC control module cannot communicate with the rest of the vehicle, I won’t get any warning lights when something is wrong with the car. Am I understanding code U0155 incorrectly?
     
  7. goshdonit

    goshdonit New Member

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    Im sorry, this feels out of left field. I just got a new head gasket installed from the dealership in November. Would they not have worked on the EGR circuit too? How would I be able to tell if that’s an actually issue?
     
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  8. ChapmanF

    ChapmanF Senior Member

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    Easiest way is to ask the car for its last EGR flow test result.

    Combined with a visual inspection of the four small EGR passages in the intake manifold. The car's built-in self test only sees overall flow, so it doesn't see differences in how those four passages are clogged, and it may be those differences that present a greater risk to the engine than any overall level of clogging. The good news is that simply removing the intake manifold for a look-see is a lot less work than fussing with the EGR system upstream.
     
  9. bisco

    bisco cookie crumbler

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    and post your repair paperwork from the hg repair. most dealers do not understand the egr circuit.
    you're right, it is out of left field, but i offer it to all gen 3 owners.
     
  10. another_tyson

    another_tyson Junior Member

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    A few days ago the 2010 Prius w/189k on it threw a P261B and had the characteristics I've read about described here indicating a water pump issue, so I replaced the water pump and the thermostat. While at it, I replaced the inverter and engine coolant. There's some pesky leakage of coolant (the super expensive toyota coolant) that I have yet to determine the source. I'll follow up with that later if anyone wants to know where it is (i.e. normal overflow because maybe I didn't burp the system correctly). I did burp the system last night, since I was no longer concerned about overheating the engine in maintenance mode waiting for the fan to come on. The reason for that is I remembered I could use the BlueDriver to monitor coolant temp and as described on this forum the fan came on at exactly 95C (203F).

    Ok so that's the background about why I'm replying to the egr circiut advice. I realized after doing my searches that afaik the egr system has been untouched. So in the next few days when parts arrive I'll be doing:
    • clean throttle body
    • clean the intake manifold
    • clean egr cooler
    • clear egr pipe
    • replace all gaskets in the above mentioned assembly
    • replace PCV valve
    • change spark plugs and coils (Denso throughout)
    • Perhaps an oil change (6k on the oil) and filters swap (engine and cabin) if I have the energy and patience left.

    Two questions
    1. Is there anything else that makes sense at this age and mileage that I should consider once I have all of this stuff detached from the engine?
    2. I am seeing a pesky U0155 code mentioned by OP that fell off the radar of this thread. Any ideas on that? I've seen it appear, then I clear codes and it comes back later. So something is def performing incorrectly or suboptimally.

    If anyone else is reading along, my thought after doing the earlier jobs is that the thermostat is probably much easier to replace when the intake manifold and throttle body are off (so maybe you can actually see the third screw holding the thermostat on).
     
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  11. bisco

    bisco cookie crumbler

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    best i can find on the U0155 is poor voltage to the ecu. you'd have to start at the 12 volt, and work your way back.
     
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