Check Hybrid System, P0A0F / P2111

thanks for the update, glad they got you sorted!

 

Hi Shawn, I have a 2010 prius gen 3. Having the error code of p0a0f and p2111 as well. For p2111, you can fix it by replacing the throttle body. What about p0a0f? This is caused by the fuel pump right? Did you fix it?

Thanks
Kris

 

Trouble code P0A0F is "engine failed to start", and P2111 is "Throttle actuator control system - stuck open". So both of these trouble codes could be caused by a bad throttle body.

I would take off the air filter housing and inspect the throttle body. Is the throttle body valve open or closed with the car off? Is the throttle body dirty? Clean the throttle body, then disconnect the 12v battery for a reset, and then try to start the car.

Come back and tell everyone if this solves the problem or not.

Posted via the PriusChat mobile app.

 

Thanks a lot. I will give it a try and you posted.

 

No, P0A0F is just a generic code from the power management control ECU (the orchestra conductor for the car).

The P2111 comes from the engine control module, and tells you what the engine issue is.

P0A0F is just the power management control ECU saying "I don't know what the issue is, but I cued the ECM to start the engine and he wouldn't do it, go ask him why."

 

Brian, I did exactly what you said, and watched a few youtube videos and cleaned the throttle body by myself. The car drives a bit differently, I think. The first time start after the job was rough, the whole car shook for a sec. Then it's all good now.

The cleaning process is not as easy as the pros on youtube. I felt like I was damaging the throttle during the process. Luckily the car is working now and no code so far.

Appreciate your help and encouragement again. Also a big thank you to ChapmanF.

 

Hi Brian, seems like the problem came back. I removed the throttle body this morning and cleaned it inside out. But the code is still there. The throttle valve is slightly open and not balance. TBH I have no idea what a normal throttle body valve looks like. Does it mean I have to replace it? Thanks.

 

I would buy a used throttle body and see if that fixes the problem.

Posted via the PriusChat mobile app.

 

Thanks, just replaced with a new throttle body bought online, cost about 120 Pound. Let's see how long can this last. Is throttle position sensor the MAF sensor BTW?

 

I bought a new one that made in China, seems like the seller sold hundreds of it. Let's see how long it would last. Thanks.

 

No. The throttle position sensor is installed in the throttle body assembly.

Posted via the PriusChat mobile app.

 

I have tried to search on youtube and ebay, can find onle one used throttle position sensor, is the part number 89451-47060? Where is this sensor in the car? thanks

 

I suspect that eBay seller is just mistaken about what part that is.

I think PNC 89451 would be a shift sensor, which that picture looks a lot more like:



You would have the devil of a time attaching that to your throttle.

 

Thanks ChapmanF. Looks like this sensor is inside of throttle body?

 

Right. Maybe don't get too hung up on the sensor? P2111 only means that the ECM tried to move the throttle to a more-closed position and it didn't go there (according to the sensor). So it could mean the sensor is bad and lying, or it could mean the sensor is just doing its job and telling you what didn't happen. It's good to check all the possibilities: make sure the throttle itself mechanically moves smoothly, the wiring is intact, and so on.

 

Started getting this code myself. P2111. Long story short, i started getting this code late 2024 when it started getting cold out. Could clear with my OBD and get going usually pretty quickly. Then around January 2025 the code stuck. Plus I occasionally also got P2112. Weather would warm up or I would try later and it would clear and could drive again but decided to order a new throttle body and go that route.

Prius is a 2010. 290k miles. Replaced Intake and PCV within last 50k. Just replaced the Throttle Body and MAF sensor. I have also been running a catch can for a while, probably last 100k miles or so. Drove it all last week with no issues then all of a sudden code P2111 came back. Happened while i was trying to leave work. Took 10 minutes of clearing and restarting before it finally let the engine run without the code coming back. It was also very cold out when i got the code, roughly 0F.

Need advice as to what to go after next.

 

Have you cleared the codes or cleaned the throttle body?
Error code P2111 occurs when "The ECM signals the throttle actuator to close, but the actuator is stuck (1 trip detection logic)"
Trouble Area

• Throttle actuator
  
  
• Throttle body assembly
  
  
• Throttle valve
  
  
• ECM
  

FAIL-SAFE
When either of these DTCs, as well as other DTCs relating to electronic throttle control system malfunctions is stored, the ECM enters fail-safe mode. During fail-safe mode, the ECM cuts the current to the throttle actuator, and the throttle valve is returned to a 5.5° throttle angle by the return spring. The ECM stops the engine and the vehicle can be driven using solely the hybrid system. If the accelerator pedal is depressed firmly and gently, the vehicle can be driven slowly.

Fail-safe mode continues until a pass condition is detected, and the power switch is then turned off.

PROCEDURE

1. INSPECT THROTTLE BODY ASSEMBLY (VISUALLY CHECK THROTTLE VALVE)
   
   1. Check for contamination between the throttle valve and the housing. If necessary, clean the throttle body assembly. And check that the throttle valve moves smoothly.
      
      OK
      Throttle valve is not contaminated with foreign objects and moves smoothly.
   NG
   REPLACE THROTTLE BODY ASSEMBLY
   OK
   
   
2. CHECK WHETHER DTC OUTPUT RECURS (DTC P2111 OR P2112)
   
   1. Connect the intelligent tester to the DLC3.
      
   2. Turn the power switch on (IG).
   3. Turn the tester on.
      
   4. Clear the DTCs
      
   5. Put the engine in inspection mode
      
   6. Start the engine, and fully depress and release the accelerator pedal quickly (to fully open and close the throttle valve).
      
      
   7. Enter the following menus: Powertrain / Engine and ECT / DTC.
      
   8. Read the DTCs.

1. Result
   Result Proceed to
   DTC is not output A
   DTC P2111 or P2112 is output B
   B
   REPLACE ECM
   
   A
   CHECK FOR INTERMITTENT PROBLEMS
   

 

You may find a gear like this in your throttle body.

toothless gear by MAX2 posted Feb 20, 2025 at 10:54 AM

 

Replaced the Throttle Body with brand new. Would like your opinion on this. I purchased this part from partsgeek:
Throttle Body - 2010-2021 Toyota Prius 1.8L 4-Cylinder - Replacement 30440-02245638
Part was cheap. About $95 shipped. The question is how good is this compared to something like:
Throttle Body - 2010-2022 Toyota Prius - Aisan W0133-2960483 ? Which is about $200

Haven't had the problem come back again. Weather has warmed up but I am having another issue since installing new Throttle Body.

Engine Revs high in different situations. Shortly after starting car so its not up to temp yet. Coming to Stop sign or Stop light, engine will Rev without my foot on the gas pedal. Sometimes shortly after will slowly come back down to normal. Sometimes i give the gas a tap to trigger it.

After replacing Throttle Body I disconnected battery and reset ECU. Wondering if this is a result of a cheaper part or something else like losing vacuum somewhere. Seal is good and hoses seem to be intact.

I plan on replacing the Hybrid battery in about a month or so. Car is going on 16 years old. MPG reduced to low 40s. I have an order for the upgraded cylinder batteries for $1900 no core charge.

Any advice is appreciated. Thanks