Code U0155 in 2010 Toyota Prius

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

 

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.

 

and clean the egr circuit before the head gasket blows

 

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.

 

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.

 

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).

 

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.