Break down today. Pulled codes. Need feedback on it.

I had a breakdown today with my 2007 Prius and got the red triangle and the car icon with the exclamation mark on the MFD. The car shut down and I had to pull over.

I pulled the codes with Dr Prius and this is what I got.

P3190
P0171
P0420
P0A0F

The P3190 is confirmed and the others showed as pending earlier. The Dr Prius full battery test also showed P0A0F which says engine failed to start.

From what I can see the hybrid battery seems balanced. Voltage difference around 0.04 to 0.13 and internal resistance around 21 to 23 mΩ. Temperatures around 90 to 100°F.

Here are the numbers I saw during the battery monitor.

Pack voltage about 205 to 232 V
State of charge about 48 to 58 percent
Block voltages mostly around 14.5 to 14.8 V
Volt diff about 0.04 to 0.13 V
Internal resistance mostly 21 to 23 mΩ

I was trying to run the Dr Prius full battery test but could not finish it because it kept asking for accelerate then decelerate. It did show P0A0F during the test.

Does this look more like an engine issue than a hybrid battery problem. Anyone seen this combination of codes before on a Gen 2 Prius. Any suggestions on what I should check first would be appreciated.

 

I am googling it now to see which engine issue is more likely cause this. It leaning me toward to dirty or bad MAF or throttle body.

Bill

 

Update
Today I had my brother come over to listen to the engine since I am profoundly deaf.

He drove the car around and immediately asked how we know how fast the car is going. I told him it should show on the dash, but surprisingly the dash was completely blank. There was no speedometer, no shift indicator, nothing at all. Just a blank display, but the car was still driving normally.

We drove back to my house and then another problem appeared. I could not power the car off at all. The coolant pump was still running and the infotainment screen was still showing status. I pressed the start button repeatedly and even held it down but the car would not shut down.

I asked AI and it suggested holding the brake pedal down while holding the start button for more than 5 seconds. It said the computer might not be able to determine the car is in the Park state. Doing that finally forced the car to shut down.

After that I checked the 12V battery. It measured about 12.3 volts on my voltmeter. I also noticed the ground terminal was loose. I could rotate it by hand, so I tightened the ground terminal bolt. The positive terminal was already tight.

After tightening the ground, we started the car again and the dashboard finally came back on and everything appeared normal. We drove around a bit, parked, turned the car off and back on again, and the dash still worked.

One thing I noticed is that the engine never seemed to stop running while driving, even during regenerative braking. However, when the engine actually stops running the RPM on my scan tool still shows around 1200 RPM, which I assume is because the electric motor is spinning the planetary gear set.

So now I am wondering:
Could the loose 12V ground terminal have caused all of these problems?

On a Gen 2 Prius, when the engine stops while driving, should the RPM show 0, or does it still show RPM because the motor is spinning the system?

Any feedback would be greatly appreciated.

 

I drove it today to get the state inspection and it drove good. I am averaging about 36 mpg in town, not sure if that is good or not since this is our first hybrid. So far the car has not died and the dashboard is still working. I plan to replace the capacitor soon but just wanted to get the plates on it as soon as possible.

Since it is running good now, I am thinking that loose 12v ground I mentioned earlier may have been the problem.

Bill