"Check hybrid system" failure & P0A0F code

I’d go to Harbor Freight and get 2 wheel dollies for cars.

Jack the front of the car up and slide the dollies under the front wheels and it back out.

The Prius is like any other front wheel drive car that you would tow: make sure the front wheels are off the ground and you’ll be fine.

 

see post #41

 

you need to do a load test to get the proper delta's

 

The pack looks to be at 208 volts (approximately). Sum up all the modules voltage and you’ll get where the pack is at.

It might be a bit low, so look into moving it out of its spot for the tow for further diagnostics.

 

To use the Prolong equipment, you need to install a harness.

But they have step by step instructions with pics on their website, so the install is easy .

I’d clean the egr circuit stem to stern and change out the plugs with the recommended Densi plugs .

 

If the engine shuts down when gu oun are trying to start it. It might be for a good reason. Like trying to prevent you from burning up the engine. A wild guess... have you check your coolant pump????

 

Following this discussion... Did anyone find a solution? I have an '07 with P0A0F/205 and I am pulling my hair out. IU have tested EVERYTHING!
Anyone?

 

Keep in mind that the cause of the trouble with @Jim Caldwell's car may not be the same as the cause of the trouble with your car.

The Repair Manual (more info) procedure for DTC P0A0F, Engine Failed to Start, says there should, ordinarily, be one or more DTCs stored in the engine control module (ECM), which may help you know why the engine failed to start. As I suggested earlier in the thread, have you checked for those, and if so, which DTCs did you find?

If you’re not finding any DTCs in the ECM, can you at least access the Data List for the ECM, to prove that the ECM is working and that your diagnostic system or scan tool can communicate with it?

 

Thanks for your response Electroingenieur! I won't try to pronounce that.

The code previous was P0121which Does not seem to appear any more... just the P0A0F code. So the throttle position sensor... Just to back up a bit, this car belongs to a friend's son and they replaced the throttle body with a used part from a junk yard. The original part was faltering, as far as I know. The original part was causing the butterfly to "chatter" at idle and I believe the above P0121 code was thrown at that time.

They turned it over to me since then because they felt it was over their head. The car is a no start currently. I have tested EVERYthing as I have said, including MAF, fuel pressure (43 psi), fuel pump relay cassette, camshaft position sensor, fuel injection rail, HV ECU. I have TS. We also have a 350 mAmp charger on the hybrid battery to keep it from going dead whilst I check things out. The charger is not ON while I am working on car... just for a couple of hours before or after working on it. So should I install the old TPS onto the used throttle body? Should i take it apart see if it is in need of a cleaning? What are the next steps please!

 

you are overlooking a couple things, and the biggest thing you are overlooking is this code!

you do NOT get P0A0F on a running engine, quit bothering about the hybrid battery

As Priucamper pointed out in his first reply, what you are hearing is the ice turning over, but it is NOT running, trust me on this, if you have P0A0F = engine FAIL TO START. it is NOT starting, its just winding they sound 99% the same winding as they do running, its the atkinson cycle way!

Try these two things ...

1. Check the injectors are actually pulsing with a test light, globe or analogue multi meter

2. Reset the 12v or do whatever you need to do to make it attempt to start the ice, while its winding over (at the stage where it sounds like started but really its just winding) spray some sort of engine start spray or alcohol based whatever down the throttle body and see if it actually starts


good luck

 

Ozmatt, I realize the difference between engine spinning and actually starting.
I tried the starting fluid in the throttle body and yes, the engine did attempt to kick over once or twice while spinning.

I am using TS with AllData.

 

Well, not so much to do with the Atkinson cycle as just the way the engine gets started.

Gasoline engines typically idle at around 1000 rpm. Conventional cars have a starter motor that only cranks the engine at somewhere around 200 rpm, just enough for it to start firing and shake/splutter its way up to idle speed.

A Prius has a big electric motor MG1 that just goes and spins the engine right up to idle speed to begin with, and then the fuel and spark get turned on. That's why the cranking sounds just as if the engine started.

 

Chappy, that’s all great and thank you! I’m trying to get the bigger running again! What happens is: I clear codes, spin engine, no start, code comes back!
Where to go from here?

 

there is hardly no difference that's the thing,

if you have P0A0F its not starting so you think you know its starting, but the laptop is telling you its not

good luck with it, hope you get it sorted