Throttle body doesn't work after cleaning

I'm suffering from a cascading series of failures with our 2010 Prius. We had a check engine light yesterday but no indicator what the problem was and it was running fine so my wife took it to work. Upon trying to return home it was running rough and she only made it a mile before all the dash lights came on and it died. I picked up an OBDii scanner today and it returned error code P3190, which from what I can gather is a general "engine running rough" code. Much Googling pointed me to the possibility of a fouled throttle body, so I took a look and sure enough, it was very funky and there was even a small pool of oil in the bottom beneath the butterfly. I figure I'm going to have to do the spark plugs too but I'm still working on my Ph.D. in all the various dialects of the Japanese language so figured I'd see if it runs first. I cleared the error code with the scanner and it fired right up, ran rough for a few seconds, then settled into a nice idle. But when I went to goose the pedal a little to see how it revs, nothing. Like the throttle body control isn't even hooked up. But it is. I took it all apart and put it back together again, being very careful to make sure I have good solid connections at both the throttle body and the only other wiring harness I disconnected at the top of the air cleaner housing. Still nothing.

Could I have somehow destroyed the throttle body control just by gently opening and closing the butterfly manually? Every how-to guide I could find said to go ahead and do that.

Now I'd like to test the throttle body to see if it has a fault but I can't find a wiring diagram or diagnostic. You'd think the OBDii scanner would return a code but it comes up blank. How can I determine what the resistance readings should be across which pins on the harness? Is it possible to use a variable low voltage DC power source to operate the throttle body remotely to make sure the motor is OK?

Thanks in advance for any thoughts the community is willing to share.

 

Well like I said, before it died on her it was running rough but I wasn't there so didn't have much to go on. It wasn't the check engine light it was the P3190 error code and a lot of Google hits that indicated it might be the throttle body.

One thing I left out is that I was able to get it to run a couple times this morning, but just barely for a few seconds before it would die. After cleaning the throttle body it idles fine, it just doesn't respond to the gas pedal now.

 

Thanks for your response, and here is some hopefully clarifying information:

2010 with solar roof
138,000 miles
full 125K service performed at the dealer in January (it was almost 130K miles by then)
one oil change since
never in an accident. ​

It does have a slow oil leak at the timing cover and so needs about a half quart every 2000 miles or so. Odds are at some point I added a bit too much oil which could be the genesis of my problem.

No dash lights now, no error codes on the OBDii after cleaning the throttle body.

All I did to get at the throttle body was remove the air cleaner assembly, pull the wiring harness off the air cleaner, then pull the wiring harness off the throttle body and remove the throttle body from the manifold. I didn't remove it all the way from the car because I didn't want to disconnect the coolant lines. I used carb cleaner, clean rags, and a few Q-tips and got it good and dry before reassembly. I can feel the gears moving when I manipulate the butterfly so don't think I broke anything in there but I'd like to test the motor somehow if possible.

don't think I got into the MAF at all - I might be mistaken but I believe it's beneath the throttle body to the right as you're looking in the engine compartment, and I was able to remove the throttle body without touching it it. I removed the throttle body because I couldn't get it sufficiently clean without doing so, and I wanted to clean out the manifold as well because the underside of the butterfly was really funky.

Again, my immediate problem is lack of any throttle control, which sure seems like an electrical problem but there's nothing obvious. I know my way around a multimeter but can't find a wiring diagram or any diagnostic information to tell me what to check for, hence my inquiry here.

Thanks again!

 

I just did a lot more Googling and realized the MAF is mounted on the top air cleaner housing so I did remove that as part of the assembly, but only disconnected the harness and didn't remove the MAF itself, nor did I spray carb cleaner in there otherwise molest it.

I did watch the NutzAboutBolts video and a bunch of others as well. I researched this for several hours before tearing into it this afternoon.

I sprayed a little carb cleaner inside the throttle body once I had it removed but did most of the work by wetting the rag and Qtips.

Just hoping to find a wiring diagram somewhere but at this point odds are I'm gonna have to buy a service manual.

 

DING DING DING We have a winnah! But you not only nailed the issue, you even accurately characterized my mental state.

Despite owning this car for nearly a year, I can't say I've ever sat there goosing the gas pedal while it was in Park. After having to get it towed home, I was afraid to pull it out of the driveway until I was sure it wasn't going to get stranded again. Having just had the throttle body out of the car, making sure it responded to the pedal seemed like a pretty logical test before driving away. It never would have occurred to me that it doesn't work that way.

I had left the whole intake disassembled last night so since they were easy to get to and I'd just studied up on it I went ahead and tested the MAF and MAP sensors and found no issues. I put it all back together again, and still no response to the pedal in Park, but I slipped it to N and got a little bit of rev, so went ahead and rolled the dice and drove it....to find it was probably fine all along. I just did a 5 mile round trip and everything appears perfectly normal. I double checked the OBDii again and still no codes.

Boy do I feel silly. But I once again thank you all for holding my hand and getting my through this. I spent the night tossing and turning and thinking I was about to rip into the fuel delivery system, spend hundreds of dollars, and probably be short one vehicle for at least a couple weeks but it worked out much better than I'd feared. I'll have my wife drive the C-Max for a few days until I've put the Prius through some paces but it's looking pretty good at this point.

 

Given the sequence of check engine light, then wife noticed it running rough, then Triangle of Death and engine died, followed by discovery that the throttle body was in quite really quite funky, I'm inclined to thing that the P3190 code was pointing to that as the issue. There is still a chance that my 12V battery is bad though and either the source of or a contributor to the problem. It's original to the car so 7 years old. It was dead after towing home but the emergency flashers had been on for who knows how long. It died again on me after charging a couple hours yesterday morning but I had left the OBD scanner plugged in pretty much all day so between that and doors open/interior lights I'm not sure if that was the reason or it's just done for. But I've seen plenty of comments online that a dead or dying 12V battery can cause all kinds of symptoms that don't necessarily clearly point to the battery in these cars.

As a side note, my wife's a teacher so the car hasn't been used consistently for the last couple months, and it sat for most of last week before she drove it a half hour on Saturday to get her classroom ready, which is when the problem started. On top of that, the solar panel that would normally keep the 12V battery topped off has been covered with a thick layer of ash from all the fires raging in our area the last couple weeks. I'll start washing the roof off every morning and monitor battery voltage and performance for the next few days and replace it if it dips below 12V at any point again.