So on Saturday I was on the highway going around 70 when I heard a beep and red triangle briefly popped up before I was in neutral coasting. After getting it towed home and doing some reading on here I found the am2 fuse to be blown. I got someone to come take a look at it and he pulled the p0a1d code and said that was the only code showing. I don't think he had a reader that would show the subcode. I am pretty sure my inverter pump is not working because after I replaced the fuse and put it in ready I don't see any movement in the reservoir. Does it make any sense that I'd get that code and not the code for the pump? Could it have been caused by the fuse blowing?
First thing to do obviously is replace the AM2 fuse then turn on the car ready mode in park get out lift the hood put your hand on the inverter pump which is right behind and a little bit below the rear of the driver's headlight It's got two hoses one coming out the top and one shooting out the side looks like a flat pancake thing on a gold bracket put your hand on it You should feel it vibrating That's how it feels all the time pretty much If it's making a lot of sucky wooshing noises usually that indicates an airlock and you should be low in the reservoir generally If it was making those noises and I was there working on it I would squeeze the hoses that go in and out of the pump and see if the noise changes as I squeeze the hose or hose is like milking a cow kind of and when I did that squeezing and let go of the hoses the reservoir should go down if there's an air lock and I'm more or less clear it by squeezing the hoses Not very much of a loop through the bottom of the inverter to the reservoir out to the other nipple and back to the pump then after the coolant level went down I would top it back up water or Asian red until it stays at the full mark even when running. If all of this works out watch it for a couple of days this fuse being blown is probably what set the code now that the fuse is straightened out and the pump seems to be running clear the code drive and if you have the luxury of having a code scanner you can leave in the OBD port and have the app up on your phone or whatever it is you're doing you can monitor data as the car moves more than likely there was nothing wrong but the AM2 fuse and the inverter pump not keeping the coolant flowing to the inverter and the battery ECU or the power management ECU saw that as a problem also now it's not.
When I put it in ready I'm not feeling any vibration from the pump, or hearing any sounds coming from the hoses. So most likely I just need to replace the pump? I just thought it was odd that I was getting a code for the ECU and not for the pump.
If it is the pump, get an OEM one. The best price locally will generally be found by ordering it through the dealer's web site (less than a walk in at the counter) and check many dealers, the price does vary. The aftermarket ones have not been reliable. The jury is still out on Aisin though. They make the OEM one and the one they sell is identical externally. It may be that that is the same pump inside too.
... and it may be a QC reject seconds being sold as new if bought on an online marketplace. Buy these only from a reputable brick-and-mortar store, if you are not going to buy an OEM from the dealer.
So, if the AM2 fuse blows while driving, the car will immediately go dead - blank dash. It will not turn on at all until the fuse is replaced (assuming the short doesn't pop it again). If the pump shorts it will blow the AM2. If the pump merely stops pumping, then the car will operate until the inverter "gets too warm". Then it will disable A/C, then the hybrid system, and set P0A93 (inverter cooling system performance). Depending on the temperature and use, you can go for weeks with an inoperative pump, or maybe only a few hours. Point is, you might have a bad pump, but that won't set P0A1D (hybrid control ecu internal error). There are 20-something INF subcodes, but most seem to state that you replace the ecu. (I would check powers and grounds first). Also I would use another scantool to confirm the code. Posted via the PriusChat mobile app.
Is it possible the fuse popping could set an ecu code though? It seems to be working now, I haven't tried to drive it much but I was able to move it around in my driveway without popping the fuse again.
You've answered your own question in post #3. ECU failures are extremely rare; but mechanical moving parts do break. I'd replace the pump first, because you know it's dead. Don't get too hung up on error codes unless you've got access to an OEM diagnostic unit. Just my 2-cents....
Usually no codes for this blown fuse. Just "car went dead like it was turned off". If that's what happened to you then I would replace the pump and see how it goes. Posted via the PriusChat mobile app.
FWIW, the original pump on my 2009 seized up and fried at 261700 mi., blew the AM2 fuse and the car quit just like the OPs. Lucky I was in a parking lot when it happened. I could smell the burned pump when I opened the hood so I disconnected it, replaced the fuse and drove the car home (about 3 miles on side streets) with no problems but the CEL had lit. I hooked up the reader when I got home and it showed both a P0A93 and P0A1D code, both of which cleared after I replaced the pump and have yet to return more than 20k miles later. My guess is the short that blew the fuse caused the ECU to 'hiccup' and throw the code. I'm with the others here, replace the pump, clear the code(s) and see if any return before suspecting the ECU. Good luck!
There are just under 60 subcodes for that DTC so knowing what the subcode is would be rather helpful. The code does not necessarily mean the hybrid control ECU is bad. For now, you know your pump is bad so get that replaced, preferably with an OEM new one, and clear the codes. Chances are the code doesn't come back, but if it does you need the subcode. There is no code for the pump, not directly anyway. You diagnose it by the symptoms. If the inverter gets hot enough it will throw a P0A93 with either a 346 or 347 subcode. 346 point you at a water pump system malfunction and 347 point you at an electric cooling fan system malfunction ... and you can (and should) remove your pump from the circuit by disconnecting the connector in the image below. When you've replaced the pump, you can clear the codes, and reconnect the pump. You should observe coolant flow in the inverter coolant reservoir when the car is in IG-ON (two presses of the Power button with foot off the brake pedal) or READY (one press of the Power button with foot pressing the brake pedal). I hope that helps.
