Code P0A4B!

Hi all... I have a code P0A4B situation, looked at a couple other threads already, gathered relevant info... but would appreciate any further insight folks might have...



I have a 2009 Prius, 178,000 miles on it...

Last Thursday, the car passed Massachusetts State Inspection, received its new sticker...

Last Sunday, on a very very rainy afternoon, we took a drive an hour and a half south for lunch. No problems.

On the way back from lunch, under a now-clear sky, we got about five minutes into our drive and got the red triangle - along with several other warning lights on the dashboard display. The little green car on the lcd Energy Monitor screen in the center of the dash also changed, to a car with a slash through it.

The car kept driving fine.

We pulled over. Consulted the manual - I should state here that I am not afraid of opening up the hood and tinkering, but I have zero expertise/knowledge to justify doing so - and after learning what the red triangle meant, decided we should call AAA, get the car towed to a service station, borrow another car to drive home with. So we did just that.

It was a busy Sunday for AAA. They were going to be a long time. Everyone else left with friends to get the other car, I stayed behind with the Prius. And got to thinking about the inspection that had just been done. What if something had been knocked loose? It was worth opening the hood, anyway. So I did. I stared at the engine, etc, for about ten seconds and said to myself, who am I kidding, I have absolutely no idea what I'm doing here.

So I shut the hood. And for the heck of it, started up the car again.

All the warning lights were gone.

I drove around for five minutes. No warning lights. We cancelled the AAA call. Drove home, on the highway, no problem. I drove around town, probably another 50 miles total, over the next couple days, no more warning light, except on one big bump the first day back, the cabin lights for some reason blinked quickly on and off. I decided to take the car in just to have it double-checked. Took it to our Toyota service center, LIA Toyota of Northampton, last Thursday.

They could not get the red triangle to come on either. But they did read the code, as above. Here's what they said.

Possible malfunction in transaxle (Motor/Generator #1 or #2) has code P0A4B (generator position sensor circuit) with detail code 253. Code is not pending. Malfunction is no longer present.

Performed visual inspection of related wiring harness etc. No obvious problems.

If code comes back on transaxle assembly will likely need replacement. $5582.92 for replacement.

That .92 terrified me.

No. But seriously.

It would be insane to spend that kind of money on a repair, obviously. And even buying a reconditioned transaxle assembly as suggested above is probably not the way to go.

But am I wrong to think that it could be something else - perhaps related to the electrical system? Again, any thoughts folks might have would be greatly appreciated...

 

Just an update on this thread - have now driven the car another 400 miles - without a recurrence of a warning light of any kind. Is that relevant? Any thoughts appreciated... TIA.

 

<grin>

Yeah. I get that - thanks for the guesses. I'm just thinking out loud myself here - thinking that if I go another few hundred miles with no recurrence, it's (relatively) safe to indulge my wishful thinking, i.e., that the code doesn't reflect an actual problem with the hybrid system but rather something more intermittent...

Only one course of action, here, it seems to me.... wait and see!