P0A0F & P3190 with normal oil level, water in engine bay [troubleshooting]

Alright, I'm in way over my head and could use a couple second opinions. To start, the background:

2007 Prius, ~145,000 trouble-free miles. Do all the maintenance myself. Have access to my sister's 2004 Prius (with ~215,000 miles on it) to swap out parts if need be.

Used car to power a 300W inverter while camping, rained lightly overnight on open engine bay. The cover for the fuse box / relay box was off as that's where I hook the inverter up. Car stopped running the ICE at some point over night, 12V drained due to inverter, car was dead next morning with P0A0F & P3190. The ECU shut the car down (miraculously) before the traction battery fully drained, so it only killed the 12V battery. Fuel is around 75% (filled it before camping, usually uses ~20% so I'm thinking it ran nearly the whole night before dying).

Got a deep cycle battery and jumper cables to both recharge my 12V and keep it charged while troubleshooting. Took out coil-on-plugs to check for water, they were all dry (it was a light, but persistent rain).

Pulled DTCs, got P0A0F/204 & P3190. Reset codes, allowed car to fire up for ~15 seconds, then it shut down again with the same two codes. When it fires, it starts at a low RPM, and slowly glides up to around ~1100 RPM, then shuts off. TS shows no misfires or other clues, but it's a big complicated program and I'm not particularly familiar with it.

Took the MAF out, cleaned it. Cleaned the throttle body. Checked the oil for the hell of it (halfway between low and high, change the oil myself). Car will start and run for ~15 seconds, but then exits READY, sets the DTCs and resumes it's triangle/turtle/send-help-please. Smelled the exhaust, sure smells like it's firing. The TS seems to suggest that it's firing, it's just running with "low power" so the ICE ECU shuts things down, which then throws the hybrid ECU code.

Did a TON of reading on the boards here. The only thing that I can think of is that perhaps the throttle motor died from getting rained on: 2007 had to be towed | PriusChat This however suggests I should be seeing other DTCs: Engine stopped, throttle body blamed. Options? | PriusChat

It's hard finding information about the throttle motor, because almost every search result comes up with throttle body cleaning. Is it feasible to swap motors between the two cars, or preferred to swap the whole throttle body (has coolant lines = PITA?). Looks like if I can move throttle motors, I can use this as a guide: TB cleaning

The other problem is my hybrid battery is down to around ~20% charge. Can I put it in the 2004 Prius for a while to charge it back up, or is swapping battery packs not that simple?

I'm slightly financially challenged, and don't need this as my primary vehicle, so a take-my-time, DIY approach is very preferable to taking it to a dealer and throwing money at the situation.

Help me Obi Wan Kanobi, you're my only hope...

 

1. Yep, recharged, holding 12.85VDC
2. Yes
3. Planning on swapping them out today. Or at least, getting one of the two Prii torn apart so it's easier to move things around.
4. Not sure, other than it got gently rained on overnight. I'd assume it'd be like hitting it with a watering can...
5. I'll see if I can't find links to the manual to make those resistance checks, especially of the throttle motor.

The car only runs for ~15 seconds after resetting the codes, despite the MFD showing the engine charging the battery while it's running, I think each run cycle is a net loss for the state of charge.

 

I got the the throttle body apart. Read the resistance across the motor, and it shows 0.0 Ohms (not 0.3 Ohms) Anyone ever read the resistance across the motor before, 0.3 to 100 Ohms seems like a ridiculous range? If the resistance really is 0.0 Ohms, I assume that means I have a shorted motor on my hands, an easy enough fix.

I think my freeze frame doesn't suggest there is an issue, unfortunately:

Code:

Throttle Idle Position    OFF    OFF    OFF    OFF    OFF   
Throttle Require Position     1.2     1.2     1.2     1.2     1.2    V
Throttle Sensor Position     8.2     8.2     8.2     8.2     8.2    %
Throttle Position No.1     1.2     1.2     1.2     1.2     1.2    V
Throttle Position No.2     3.0     3.0     3.0     3.0     3.0    V
Throttle Position Command     1.2     1.2     1.2     1.2     1.2    V
Throttle Sens Open Pos #1     0.7     0.7     0.7     0.7     0.7    V
Throttle Sens Open Pos #2     1.8     1.8     1.8     1.8     1.8    V
Throttle Sens Open #1(AD)     1.2     1.2     1.2     1.2     1.2    V
Throttle Motor    ON    ON    ON    ON    ON   
Throttle Motor Current     0.7     0.8     0.7     0.7     0.7    A
Throttle Motor DUTY     25.0     25.0     25.0     25.0     25.0    %
Throttle Motor Duty (Open)    11    9    11    8    8    %
Throttle Motor Duty (Close)    0    0    0    0    0    %
Throttle Fully Close Learn     0.5     0.5     0.5     0.5     0.5    V

I'm going to use a different meter today for a second opinion.

 

Alright...I'm back to working on my car again. Car has sat in a heated garage for about a year and a half now: water should no longer be an issue.

I gave the car a fresh start attempt today to get freeze frame data. My nose reports that I do get the faint and familiar whiff of combustion. The B1S1 temperatures were 149'F to 152'F from seconds 13 to 15 (thanks freeze frame!)...the B1S2 climbs as well, from 122'F to 123'F over those two seconds. So, something is going on that involves fuel, injectors, spark plugs, and whatnot...but the ECUs are seeing the result as "not enough torque". :/

The full codes are still P3190 + P0A0F-240. The troubleshooting documentation suggests if there are other codes besides P3190 to fix them first ("If any other codes besides P3190...are output, perform troubleshooting for those DTCs first.")...that means to fix the P0A0F-240 first. But then under the section for P0A0F-240 it says this for the inspection proceedure: "READ OUTPUT DTC (ENGINE)". Ok, that's P3190...

P3190:

"Following conditions continue at a fixed
engine RPM or a fixed length of time:
• Communication with HV ECU is normal (check)
• Engine RPM is a fixed value or more (1207)
• Engine start mode is not active (check)
• Target torque is a fixed value (22.25kW)
• Ratio of estimated torque against target
torque is less than 20%" (estimated torque is listed as 0 Nm, actual engine torque is listed as -12 Nm)

P0A0F-240:

"Abnormal signal input from ECM
(abnormal engine output)
• ECM (must mean "torque ratio according to ECM signals provided to HV ECU is bad"?)
• SFI system" (must mean "perhaps the torque ratio is crap because there's an actual problem with the engine"?)

I'm wondering if the "water under the hood" isn't a false lead: I found that some of my dash lights didn't work due to J6 having one of the two battery leads being broken between the connection and the body ECU (as per Dome power loss with VSC light on | PriusChat, fixed by running a new conductor between J6 and A1-13). I went about that diagnosis very slowly and methodically, checking various systems that did and didn't work, then checking voltages at various points (while in OFF, ACC, and ING modes), and then finally checking continuity across the suspicious conductors to track the problem down to a specific point in the wiring / system.

I'm thinking a mouse or squirrel might have hopped up in there during the night while it was raining and had it's way with things...one of those things being the conductor between J6 and A1-13, and maybe another one of those things being important for the ECM or HV ECU to operate the engine, or tell if the engine is operating correctly? I've got about half the dash apart so far...but I am pretty sure I'm going to end up taking the rest of it apart, as well as all of the wiring looms, to try to find a bad conductor somewhere. My 40 hours in so far looks like it might end up being 120+

I'd like to be as methodical in troubleshooting both P0A0F-240 AND P3190 as I was with the interior lights...but this is a bit more complex than the interior lighting circuits...

I have fresh freeze frame data from Techstream for both the Engine ECU and the Hybrid ECU, if that pile of information would make sense to anyone (perhaps something would stand out as "oh, that's not a good reading and is causing these error codes, you'll want to find and troubleshoot X object to root out the cause").

It's probably something silly like the fuel pump...but there are so many "it could be something silly like X, Y, or Z" that I'm completely overwhelmed at the moment.

Anyone have any suggestions based on my ramblings so far?

I think I'm going to have to do this, for everything else besides the throttle body motor.

5. The Toyota repair manual offers resistance checks of various components such as the mass air flow meter, throttle body motor, and the various engine sensors. If all of those checks are good and the fuel line pressure is > 43 psi, then it is suggested that the engine ECU needs to be replaced. See techinfo.toyota.com for details.
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I'm worried if there is a bad conductor between a sensor and an ECU those tests will be for naught. I'm mostly worried because I'm still in way over my head, it's been ~2 years, and my car still isn't running

EDIT: put the .csv of the freeze frame online in case anyone wants to see it: TinyUpload.com - best file hosting solution, with no limits, totaly free

 

Update time.

&

After hours, and hours, and hours, I finally have this car running again.

There were two issues.

One was a bad connection / wire somewhere in the dash between a junction in the right and left footwells that broke the interior dome lights, clock, radio, and a few things. Fixed that with a new conductor: P0A0F & P3190 with normal oil level, water in engine bay [troubleshooting] | PriusChat

Second was the fuel pump wasn't running. Turned out to be those relay modules in the fuse box, just like hometownautomotive! Getting wet must have caused them to fail, as they switched the fuel pump on and off repeatedly in the rain. Going to examine it closer to determine best I can *how* it failed. I replaced them both just to be safe, I think it was just the B module that was completely kaput (with the C/OPN relay), but figured it couldn't hurt to do both and I'd got them cheap from a wrecked prius. Should have just swapped them for the hell of it a long, long time ago.

Current step is to figure out how to fix the cut I made in the fuel line while diagnosing and troubleshooting things...looks like I need some tool to flair the nylon tubing to permit the original fitting to fit back in.

If I learn anything useful during reassembly, I'll post back here

 

tl;dr: two sensors and a computer to calculate fuel tank level, zero sensors for fuel pressure :/

I was pretty overwhelmed by the lack of direction provided by the error code:



During the initial troubleshooting and diagnostic stages, the traction battery drained too low so I needed to figure out how to recharge it. Luckily around the same time, my sister got a Prius and I learned you *can* simply swap the batteries around. And then, her battery pack started acting up on her. Shelved my project while I let her borrow my battery and I refurbished her battery (with one imax charger). So that took forever by itself, learning, cycling, balancing, etc.

Finally got to the point where I could start back in on my own prius, and work had picked up to the point where I could only sink a few hours a week into it. I also picked up a beater prius (crazy cheap because it needed a lot of basics all at once that I just did myself (except the windshield!!)) so I could put my sister's car back together for her instead of needing to recharge my traction battery with it every so often. I originally intended it to just be a traction charger on wheels, but it is in such good shape mechanically that it's currently my daily driver (dealer maintained w/ full maintenance records, 200k and doesn't burn a drop of oil, has had a transmission fluid change ~100k (and another when I got it), etc etc)

When I had a few hours and some motivation to skin my knuckles, I stripped the car down to basically just having the front seats, steering wheel, and the start button on the dash (had to take the entire dash out to track down and fix the bad conductor). Took a lot of the top of the engine apart along the way as well.

Was working through troubleshooting in what I thought was a sensible fashion, starting with the areas that got the most rain and when that started all looking ok, I then assumed a second conductor got chewed through(or whatever) and was blocking / messing up some signal to / from the ECU. The fuel supply was pretty far down my list, because with the testing I'd done along the way the other circuits in those relay blocks worked, so I incorrectly figured the whole module was likely to be working.

Also incorrect was my sniff test for combustion: the fuel rail holds a bit of gasoline, so I now assume whatever small amount was dripping through the injectors was fooling me. Draining the entire tank, lines, and fuel rail itself of ~3 year old gas was a fun job. Some folks don't feel that's necessary from what I've read here (due to the bladder in the tank), but during my initial eval of "does the fuel pump even work if I wire it to an external 12VDC battery" I saw the old gasoline was disturbingly dark and cloudy.

When I got around to methodically checking the modular relay blocks themselves is when I figured "even though this one checked out fine, might as well replace it anyway" which led to "might as well replace the other one anyway even though I haven't gotten there yet", and here I am with a working car. A long, long, long time later.

But on the plus side, I know how pretty much every piece of it works by this point (it's a big robot basically, that we just ask to do things and it determines the best way to get that done)? I guess all drive by wire cars are like that, the hybrid ECU adds another abstraction layer to the mix

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The fuel line connector needs a clamp + press to fit back into the nylon tubing, it's not a flare tool but instead a simple ram. Some people build their own, I am going to see if I can find one to rent from a local parts store, something like a "Dorman 800-301 Fuel Line Repair Tool"

 

The fuel pump relay obviously had gotten a little water in, and that directly led to the relay's failure. Lesson learned, use the trunk battery access for inverters. Also, a first place to look for folks in the future who have the hood open, the fuse box exposed, and a bit of rain leading to P3190 etc:



It should be water safe with the fuse box covered and the hood up (even a power wash shouldn't get water back up under the cover enough to collect and rust).

The Dorman 800-301 Fuel Line Repair Tool made short work of the nylon fuel line. Instructions are nearly impossible to find online: http://static.dormanproducts.com/document/800-300_IS.PDF Some folks recommend heating the tubing, I instead applied an extremely small amount of vaseline to the ramp surface: it went in without issue, and hasn't leaked over the past ~1 hour of engine operation. I'll continue to check it sporadically for dampness over the next couple years. Note, I only purchased the tool and reused the OEM fitting.