[jbjohnson]

My 2016 Scion iA idles rough, and I think I have pinpointed the problem to it happening only when the brake is applied. I took it in to the Dealer to have that checked, but of course they couldn't find anything wrong! It is not right that it should do that and it annoys me no end when it does! I will take it to another Dealer for sure, but have no confidence that they will agree to the problem, and correct it. Are other Scion iA owners having this problem? Please let me know!




Thank You,


Joseph A. Bifulco
26 Johnson St.
Franklinville, NY 14737
Home Phone (716) 676-3234
Cell Phone ….(716) 866-5456
mailto:[email protected]

 

[Samu]

Hello, new in the forum, i happen to have the same problemb i drive a 2016 yaris, my problem is that i had to jumstart my father in law his mazda mpv, at first we gave it a few try but it wasn't working so i had to remove my battery and put it in his van and it turnd on but since then my yaris wont idles right, its keeps dropiing to 500 i guess right in the dot, and in D shift, but with the ac on, it works better but sometimes keeps droping even with the ac on, i took it to the dealer and ofcourse they did't find anything wrong and said that it was normal, i know its not normal due to before the battery thing it didnt vibrate or anything, i apricciate if some one can help me with this issue, if by jumpin the battery coul have damaged something or the computer needs a tune up. Its been 2 month now with the problem, thanks fellas.

 

[Samu]

Hey jbjohnson mine does that too, now i notice that when i push the break pedal when release i hear a lil bit of air and a schiming sound i hope its not a big deal

 

[jbjohnson]

Hi Samu,


Thanks for you reply. For sure sounds like something went haywire with the computerized system when you jumped the battery. Hope you can get that corrected for your piece of mind, and for your car's sake. I don't like it when my car idles rough, and my only connection to that is when holding down on the brake pedal. Like doing so has some effect on a brake booster pump, which puts a strain on the engine. Sorta like that. Maybe it wouldn't bother someone else, but it sure bothers me. Sometimes I want to put it in neutral at a stop when having to hold the brake down. I could tell you stories about taking the last 3 new cars I owned. It's amazing how little they know of the new technology in cars of today. You have to insist they do what is needed to correct the problem. Now they don't want to see you 10,000 miles. I'm from the old school, and I don't want to wait that long for sure. In any event I will take my Scion iA to another come warmer weather.


Thanks,
JB

 

[TheFatOne]

If you vibrate at idle with the A/C off its probably you motor mounts. violent misfire and multi cylinder misfire on start up look at my other posts. Dealers are bone heads.

 

[Kwevans90]

My IA idles rough occasionally when I am at a stop as well. I believe it is normal, I worked at a Toyota plant and there is a rough idle feature that we tested. It's purpose I'm not sure, but I wouldn't worry about it.

 

[WilsonT123]

Hey guys,

My 2016 ia automatic idles roughly from time to time when the brake is applied. Enough for me to be notice and become annoyed by it..


What should we do???

 

[iAoperator]

mine iq did that too and ia does the same- I think it's CPU reacting to electric power drainage- poor programing, but nothing bad going to happen- it just annoying

 

[iAoperator]

do nothing- that is normal for this car electric system- when more power is reIquired CPU commands engine go to higher rews, so generator can produce more power- I know it is annoying- poor programing

 

[bluelinelife]

it's just the characteristic of a lightweight subcompact not much dampening

 

[Cooter]

I was having a rough idle as well. Plugged my obd2 reader in and reset all the sensors and whatnot and after the ECU relearned O2 sensor, fuel trim etc it idles like new. It's not rough or shaky.

 

[bluelinelife]

What did you disconnect the battery for 5 mins and reconnect

 

[Cole]

Disconnect the battery for 10 mins or so reconnect it go for a long drive on the freeway 30 mins+ then when you get off the freeway do some city driving and keep it in drive at all the lights it will vibrate for a second at the first couple lights then it stops completely this fixed the problem for me.

 

[Cole]

My vibration came back the harmonic balancer looks fine motor/tranny mounts look fine air filters are new and theres no stored codes but I've come to find out that it's normal for 4 cylinder engines to vibrate at low rpm so I'm not going to worry about it unless it gets worse or a code pops up.

 

[TheFatOne]

Still rough idle a 100k.

Idling rough and getting worse at 100k. New coils plugs and cleaned MAF to no avail. when A/C is on idles 700 and is smoother but still rough. Idles 500 and rough with no A/C. Rough idle without A/C is motor mounts if there is no misfire. violent misfire check my other threads.

 

[Bry's iA]

Hello, my 2017 iA (38k miles) started idling rough only after doing highway driving then coming to a stop. Now it idles rough doing round town driving. Dealer said...if check engine light isn't on they want $185 just to look at it even tho I have the platinum extended warranty...When it drops to 500 rpm when breaking, i pop it in neutral and the rpms come right back. It is annoying but i dont think its causing any damage.

 

[TheFatOne]

Rough Idle and check engine light at 105k solved. Our Scion Ia's are direct injection engines. Direct injection engines have a problem with Carbon fouling and if you have a rough idle please have the Carbon cleaned from your intake tract and valves. This should cost about $300. Mine went all the way to a P0300 misfire code and it costs me $600 to remove the intake. Dealer tried to sell me new car and said engine was no good. I reputable shop call Salem Brothers (AZ) was willing to try and fix the Carbon build up and the engine is fine. Most dealers will just say you need new engine and try and sell you a new car. There are risks with having let the carbon build up for a 100k. It may not be possible to clean all the carbon out and dealers won't take the chance. Shop said to clean Carbon every 20k. I tried everything I could think of to fix my rough idle. I had a warranty to 100k and dealer's just told me that there was nothing wrong. Manuel says nothing about this needed maintenance. This affects other cars with direct injection as well. Rough idle is more noticeable with A/C off.

Update. Rough idle without A/C of at 500 rpm is motor mounts if bonehead dealer says there is no misfire. Also do a GDI intake valve service every 20k. see my other threads.

 

[TheFatOne]

Still having issue with rough idle and misfire. New coils, MAF, plugs, and carbine clean of the intakes has not solved. P0300 code and volant misfire at 105k has not gone away at 125k. I do suggest having GDI cleaning about every 20k. Mechanics say that there is carbon buildup in the intakes from the Direct injection GDI also they say the shaking at 500 rpm is the motor mounts. If there is any good mechanics out there please help.

Rough idle at 500 rpm with A/C off is motor mounts. P0300 code is carbon buildup in intake valves. see other threads

 

[Fuggyew]

Still rough idle a 100k.

Idling rough and getting worse at 100k. New coils plugs and cleaned MAF to no avail. when A/C is on idles 700 and is smoother but still rough. Idles 500 and rough with no A/C. Any suggestions as to how I can sell this thing?

Cleaning the maf isnt a fix if its malfunctioning try a new maf and if that doesnt fix the problem then its something else bc if you got new plugs and coils and only cleaned the maf with no change then its obvious its the maf!!!

 

[madrew]

I have the same problem. Idle drops from 750 rpm to 500 rpm when in gear (auto trans) and brake pedal is applied. No AC on, in daylight with lights off. If you pop the brake light switch out of the mounting bracket pushing the brake pedal has no effect on idle rpm so it doesn't seem to be vacuum booster related. Seems like it's engine management related. In response to others saying "this is what small 4 cylinders do at idle", I strongly disagree. No engine should ever be dropping below 750 rpm at idle, unless an immediate load is engaged and then the idle control should return it to 750 rpm. Mine will stay low until the brake is released. The shudder is from too low an rpm, not from being a small 4 cyl.