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Toyota Prius P0A0F And P3190 No Throttle Response: SOLVED

If you are a Prius owner who is suffering from an instant occurring trouble code P0A0F And P3190, take a look at what caused mine and the repair for it.

There are few things worse than getting a trouble code on your Prius when you least expect it. Is it a failed hybrid battery? A water pump? Head gasket? The swarm of thoughts can quickly strike fear into your heart.

Rest assured you are driving one of the best-designed vehicles, a Prius. More than likely, your problem is not as bad as it seems. In my recent event with these exact trouble codes, I learned not to panic but be analytical with the issue.

What Causes A P0A0F And P3190?
Both of these codes first need to be broken down. If you do not understand the description of the code, you will never find the root cause for it.

A P0A0F is defined as Engine Failed To Start. A P3190 is defined as Poor Engine Power. While these codes seem vague, they are pretty helpful in the diagnostic process.

The possible trouble areas for a P3190 are:

  • Air induction system malfunction.
  • Defective throttle body.
  • Improper fuel pressure.
  • Defective engine.
  • Defective Mass Airflow (MAF) meter.
  • Vehicle is out of fuel.
  • Defective Engine Coolant Temperature (ECT) sensor.
  • Defective crankshaft position sensor.
  • Defective camshaft position sensor.
  • Defective Engine Control Module (ECM).

The possible trouble areas for a P0A0F are:

  • SFI system
  • Faulty Power management control ECU

So what causes these two codes could be anything on this list, and that is where skill comes into play.

How To Diagnose These Two Trouble Codes
These codes can be as easy or as hard as you make it. The first thing you need to do is consider what it is you are dealing with. Prius is a well-built machine, so things like an engine ECU or bad sensors will not be on the top of the priority list.

Sensors should be checked and verified, but only after you do the stuff that easier to access. Looking at the list, I know instantly I will check the fuel level and the mass airflow sensor. Why? Because of how easy they are to do. Add fuel (at least 3 gallons if low), and checking the MAF takes less than 5 minutes.

2004 Toyota Prius Air Intake Box

If both items check out 100%, you can move on to testing sensors and work your way down to the more complex to test things. Ruling out the easy stuff can help you better understand what you are working with.

If you think about this logically, how possible is it that a MAF sensor or no fuel is the issue over a bad ECU? Common sense tells me that Prius has a meager rate of ECU replacements, hence starting with the easy stuff.

Sure enough for me, there was debris in the MAF sensor. A quick snag with my tweezers and a rinse with MAF cleaner, and the Prius was back in business.

2004 Toyota Prius MAF sensor Debris in MAF Sensor 2004 Toyota Prius

I know that trouble codes are confusing; trust me, I was not always as brilliant as I am now. I spent a lot of time learning how trouble codes work so I can diagnose them. Now that I do know, I am happy to share my knowledge with other Prius owners.

If you check your Prius with these codes and the MAF is ok, and there is fuel in the tank, let me know. I am happy to advise on how to proceed next.

That is all for today. Please find me on Twitter @the_hybrid_guy or Facebook in the Toyota Prius Owners Club, and remember Today's Adventure is Tomorrow's Story.

If your Toyota Prius Rear Brake light assembly has low power output take a look at this write-up to see if it can help you.

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Peter Neilson is an automotive consultant specializing in electric cars and hybrid battery technologies. He holds a Bachelor of Science in Automotive Service Technology from Weber State University. Peter can be reached on Linkedin and you can tweet him at The_hybrid_guy on Twitter. Find his page on Facebook at Certified Auto Consulting. Read more of Peter's stories at Toyota news coverage on Torque News. Search Toyota Prius Torque News for more in depth Prius coverage from our reporter


George Cardona (not verified)    August 6, 2022 - 8:19PM

I get on mine P3190 Foxwell scanner POOR ENGINE POWER does not say anything else. Car runs for 5 seconds stalls then triangle and same code. I watching another fellow using computer with software Toyota uses called Tech Stream well you can find different versions of it plus an app to use so it by passes the registration. Bought cable from and been all week trying to get it to connect and the key is has to be 32 bit operating system downloaded windows XP 32 and it works Using XHorse there are write ups on this I have downloaded Windows 7 32b going try that next.

Philip Morrissey (not verified)    August 24, 2022 - 2:19PM

I had the red triangle and engine check light on my 2004 Prius and was getting a 3191 on my OBD. The car seemed to be running fine. I cleaned the MAF sensor and surrounding area put it back together and there was no triangle or engine check light. However when I plug in my OBD 2 it still shows a P3191 code. Car seems to be running fine? What should I do next to try and get rid of this?

Gregory Lane (not verified)    December 28, 2022 - 3:45PM

Just bought a 2007 Prius at auction and it only had check engine light with P0300, P0301, P0302 and P0303 codes. I changed oil, oil and air filters, EGR valve, spark plugs, all 4 coil packs and cleaned the MAF sensor. After that, I took in on a 2 block test drive, the red triangle appeared as well as the check engine light, with P0A0F and P3190 codes. Idles rough, exhaust smells and no power when running down street. After red triangle came on, it would not kick the engine back on. It has a new GreenBean hybrid battery and I put a new Napa 12v battery in it. What next? I was thinking clogged cat, but no codes for that.

Dan Clear (not verified)    January 19, 2023 - 4:36PM

First off thanks for the good information. I had this issue and replacing the MAF fixed it, however I recently had this happen again after 600 miles or so. When I shut off the car after the warning the car starts right up and runs a few minutes. But after 10 minutes or so it gives me the P3190 error. Just checked and the MAF is clean as a whistle, is it possible my screws on the MAF were not tight enough? They were tight but probably not as tight as they could have been. Thanks in advanced. 2009 prius, 181k miles.

William Wallace (not verified)    November 7, 2023 - 4:45PM

Hello, I'm having difficulty with a 2006 Highlander 4wd Hybrid, I've examined and cleaned the MAF, replaced the 12v battery, replaced the hybrid battery, the fuel pump and cleared the codes. These are the remaining codes Hybrid Controls P0A0F-204, U0129-222 Engine and ECT P102, P3190 Cruise Control U0129 ABS/VSC/TRC C1259-150, C1310, U0293-152
Any help would be greatly appreciated. Thank you