Yaris Sedan Throttle Failure- Electronic

[ras3448]

Hello Yaris World. I'm now a dual Prius/Yaris owner and enjoying the experience, but my Yaris has hit a major setback, mostly mea culpa.

I had a real long post, but it logged me out when I clicked submit :(

Anyway, I believe that I reversed the poles when I was jumping my '07 Yaris Sedan. Now I am getting no throttle response from the accelerator pedal. Also, the Check Engine, ABS, and BRAKE lights remain on. All other functions work, including lights, radio, power windows, A/C. The engine starts up and idles fine, and the transmission will shift into gear and move the car, but only at idle speed.

I've read a number of other posts, and the only thing that stands out is a ScanGauge ReadOut: P0121, which indicates "throttle pedal sensor switch "A" circuit range/performance". But I'm not sure if that applies to my situation.

I could really use y'alls help, I'm having my poor Yaris towed to the dealership tomorrow to have them see what's wrong, but I'm wary of dealers. Any input is much appreciated. If you need any more details to help/diagnose/hypothesize about this, please tell me and I'll be refreshing this page obsessively.

Thanks!

[bronsin]

Well the computer has thrown an error code and it would seem has put the car into limp home mode.

I would disconnect the battery (five minutes) to try and clear the codes.

Perhaps it became upset at the crossed jumpers. Now that they have been removed perhaps clearing the code will make things right.

But if something got fried when you mis jumped it the problem is still there and pretty soon the code will come back.

I predict people will soon arrive who know more about this than I do.

Good luck and tell us what happens!

[CTScott]

Have you gone through and checked all fuses? I am not sure about how much reverse polarity protection the various systems have, but I would start with the fuses. You may also want to disconnect the battery for a couple of minutes and reconnect to reboot all systems that are continuously powered.

[ras3448]

Hey guys!

Just got off the line with the dealership. Not what I expected...
They said, as expected that the 10amp, 30amp, and ABS fuse need replacing, $5 bucks each. They also said that the battery needs to be replaced ~$85.
Then this next part threw me a curveball, they said that the throttle body needs cleaning, because fuel varnish had built up on it, causing it to stick, and not allowing the electronic throttle control to control the idling speed appropriately. They said I wouldn't have noticed this until the battery died, because when the battery dies, it releases the throttle body, and causes it to stick in the wrong position. So, this symptom, which I had never experienced before, will cost me $185 labor and $96 for the throttle body cleaning.
Does this sound right to y'all? btw, Yaris is '07 sedan w/81K miles, with a factory 3yr Interstate battery.

Thanks! Any input much appreciated.

[bronsin]

Unless you were having a pROblem I would say it a bogus add on BS thing to pad dealer profits.

Whenever I hear about someone bringing their car to a dealer to fix, say, the water pump, they pressure you to do other things they "found" were bad.

I had a fuel injector go bad. Diagnosed it myself. Wife took it to a shop. They talked her into a "fuel system flush" for $200 that did nothing. Then they charged $300 to change the injector.

I didnt have time to take it there myself. That is how they treat you if they can get away with it.

If they havnt done the TB yet tell them thanks but no thanks.

They can always do it another time if theres a problem.

[CTScott]

I agree on the throttle body part being bogus. Shutting the key off and having the battery disconnected both leave the throttle in the same position.

[ras3448]

Well, I guess I'll have to bite the bullet on this one. The first thing they did when the got the car was clean out the throttle body, so I'm stuck with that $300 bill.
I'm not too upset though, considering this car has gone 89K miles now, without any shop visits, just oil changes and new tires. I've learned my lesson though, I need to talk to you guys before I let a dealer tech poke around. The situation was tough though, because I was managing the dealer from out of town, and my fiancee needs the car to get around (home health care).

Thanks for the input bronsin and ctscott.

It was cool to learn that the throttle on the Yaris uses fly-by-wire throttle. I sure love my prius with its fly-by-wire everything, and I think I'll like the Yaris as much in time. Are we gonna see some more all-electric systems like steering or transmission in the new Yaris model year roll-out (2013?)?

[Z00KA]

Did you authorize the "throttle body cleaning"? Horrible that there is no way to check to see if that actually cleaned it. They wonder why everyone thinks that they're crooks! This is the reason I thank the good Lord for this group and ALWAYS do the work myself!

I had a friend's wife take a Prius into the local "stealer" for an oil change and $600 dollars later, they charged him for brake fluid "flush and fill" (can you imagine?), radiator flush and fill, the oil change, refill on the nitrogen in the tires, and a few other things that one cannot check to see if they actually did the service.

Here's the "kicker"...the Prius only had 10K miles on it, but they told her that..."all this stuff is in the scheduled maintenance and needs to be done"...she didn't know any better. Of course my buddy was livid when she got home and informed him of what transpired. 10 minutes later he's on the phone with the service manager threatening to grab a local TV station camera man and crew and come pay him a "visit"...he ended up paying $40 for the just the oil change!

People wonder why this great country is going in the "shitter"...it all adds up!

[ras3448]

I didn't authorize anything. I got off my night shift at 8:30, called in, by which time the service guy had already opened up the Yaris and done the 'cleaning'. So I was already $300 in the hole before I was told anything.

On another note, I've heard that since I'm approaching 100K miles, I should be looking into a transmission fluid change, A/C coolant top-off, A/C belt replacement. I'm a bit hesitant to invest in any of these yet since the car has had zero transmission symptoms, and a perfectly steady mpg (32.1) for the last 20K miles. I'm really interested into getting into doing my own service too

[Kioshi]

Originally Posted by ras3448

I didn't authorize anything. I got off my night shift at 8:30, called in, by which time the service guy had already opened up the Yaris and done the 'cleaning'. So I was already $300 in the hole before I was told anything.

On another note, I've heard that since I'm approaching 100K miles, I should be looking into a transmission fluid change, A/C coolant top-off, A/C belt replacement. I'm a bit hesitant to invest in any of these yet since the car has had zero transmission symptoms, and a perfectly steady mpg (32.1) for the last 20K miles. I'm really interested into getting into doing my own service too

Regarding your throttle body cleaning...$95 is tooooo much. I have 74550 km on my car. And...i cleaned the throttle body myself. Bought the throttle body cleaner and MAF sensor cleaner at Kragen Auto Parts for $15. It took me about 2 hours to clean both, take out and put back together.

It is simpler than you can imagine getting to the throttle body and cleaning it with the solution. DO it yourself, honestly..use that money on gas or buying something else.

[1NZYaris1]

i have only 1 thing to say to you,
do you replace your engine oil when it is due or once the engine wont turn over

[bronsin]

Originally Posted by ras3448

I didn't authorize anything. I got off my night shift at 8:30, called in, by which time the service guy had already opened up the Yaris and done the 'cleaning'. So I was already $300 in the hole before I was told anything.

In NJ that is illegal. You must be informed in writing and give your permission for ANY work to be done.

Look up your Attorney General and call and ask...

[auxmike]

I want to clean my throttle body too, but I'm kinda scared to take it off! Never fooled with drive by wire and I'm concerned that the spray could melt some sensitive motor and then I'm SOL.
Can the TB be unbolted and swung down without removing the coolant hoses?
Is there coollant between the TB and intake that will pour out upon removal?

[CTScott]

Originally Posted by auxmike

I want to clean my throttle body too, but I'm kinda scared to take it off! Never fooled with drive by wire and I'm concerned that the spray could melt some sensitive motor and then I'm SOL.
Can the TB be unbolted and swung down without removing the coolant hoses?
Is there coollant between the TB and intake that will pour out upon removal?

Yes, you can unbolt it and move it around to reach both sides of the throttle plate. I had mine off when I installed my supercharger. I didn't take pics of it swung out of the way, but here is is just before removal:

[ras3448]

Hi guys, I have an interesting situation.
Following the events I described earlier, I had a significant jump in MPG, from a nearly rock-solid 32 mpg, to roughly 40mpg. My fiancee reported it first when she filled up and calculated 37 mpg, but I assumed she had miscalculted. I then drove back and forth from Austin to Dallas, and reported 40.7 mpg!
This is after a dealership service visit which included a couple of new fuses and battery, and a throttle body cleaning. How is this possible? Any theories?

[bronsin]

Before the Dallas trip where were you driving to? I mean how many miles?

TB "cleaning" would do nothing to improve mpg.

How many miles on the car?

[ras3448]

90K miles on the car.
I've been tracking mpg for over a year, on every tank (part of my post-prius OCD), and have always been stymied by the lower than average 32 +/-1 mpg. That 32 was recored regardless of all city/ all highway driving, which was also super weird.