IS - 3rd Gen (2014-present) Discussion about the 2014+ model IS models

Low rmp shutoff.

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Old Jan 26, 2019 | 06:33 PM
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Default Low rmp shutoff.

Has anyone experiencing a random shutdown on is250 awd? My car idle below 1000 rmp for a couple day now, the rmp jump up and down. After a couple second it goes as low as 500 rpm when the weather is cold outside then shut it self off when I pushed the acceleration. I never experienced this befobe, this is a first time. The car is only 36666 miles, been running premium gas.
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Old Jan 26, 2019 | 06:41 PM
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Check the coolant system to see if it's low. Sounds like you have an idle air control issue.
Coolant flows through the throttle body as part of the idle control system.

Also check your intake as well..maybe sure all connections are tight and no hoses are off or loose.

Did the check engine light come on?
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Old Jan 26, 2019 | 06:46 PM
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I had a similar issue on my 2016 is200t where while in park, my RPM would fluctuate between 800 and 1000 rpm. It sounded like it would stall when it hit 800 but would quickly ramp itself back to 1000 rpm. Not sure what it was. Dealer said the car doesn’t have an IAC valve anymore
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Old Jan 26, 2019 | 06:54 PM
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Other 200t owners have mentioned that idle issue...seems like it's either a problem or characteristic of the vehicle.

And yes, the car doesn't have an IAC valve any longer as the throttle bodies have a motor to control flap opening, so the ECU can open if further for cold start fast idle without driver input at the pedal.
Nonetheless, the engine coolant temp sensor can give inaccurate readings if there is a coolant leak and there is air in the system. If the air is around the coolant temp sensor instead of coolant, the sensor will not read correct, and in fact will read much higher than normal.
So in essence it won't know the vehicle is cold...when it's cold. It may think it's already warmed up, and therefore doesn't need that much fuel.

When you see an erratic idle condition, it due to either too much or not enough of one of three things: air, fuel, or fire (fire being the spark from the plugs).
An air leak in the intake system will cause a high or fluctuating idle (too much entering the engine that the ECU can't see).
Incorrect coolant temp reading...ECU is not adding enough fuel to maintain cold start fast idle.
Not enough fuel pressure...hard to check on a 250 with direct injection...and I wouldn't suggest you try either.
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Old Jan 26, 2019 | 07:00 PM
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Originally Posted by pngo
I had a similar issue on my 2016 is200t where while in park, my RPM would fluctuate between 800 and 1000 rpm. It sounded like it would stall when it hit 800 but would quickly ramp itself back to 1000 rpm. Not sure what it was. Dealer said the car doesn’t have an IAC valve anymore
Did they fix the issue? Mine is 2015. I never expected this to happen lol. Still under warranty, I might as well asked the dealer about it. For now, I still don't know what is causing it. But yeah, once it 500 it shuts off.
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Old Jan 26, 2019 | 07:13 PM
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Originally Posted by Sonn
Did they fix the issue? Mine is 2015. I never expected this to happen lol. Still under warranty, I might as well asked the dealer about it. For now, I still don't know what is causing it. But yeah, once it 500 it shuts off.
They kinda just passed it off as the ECU doing its thing... I’m not sure how to replicate and my engine didn’t shut off so I didn’t have a good reason to push on it. I did have a 1 minute video of it though showing it drop every 6 seconds.

Originally Posted by Sasnuke
Other 200t owners have mentioned that idle issue...seems like it's either a problem or characteristic of the vehicle.

And yes, the car doesn't have an IAC valve any longer as the throttle bodies have a motor to control flap opening, so the ECU can open if further for cold start fast idle without driver input at the pedal.
Nonetheless, the engine coolant temp sensor can give inaccurate readings if there is a coolant leak and there is air in the system. If the air is around the coolant temp sensor instead of coolant, the sensor will not read correct, and in fact will read much higher than normal.
So in essence it won't know the vehicle is cold...when it's cold. It may think it's already warmed up, and therefore doesn't need that much fuel.

When you see an erratic idle condition, it due to either too much or not enough of one of three things: air, fuel, or fire (fire being the spark from the plugs).
An air leak in the intake system will cause a high or fluctuating idle (too much entering the engine that the ECU can't see).
Incorrect coolant temp reading...ECU is not adding enough fuel to maintain cold start fast idle.
Not enough fuel pressure...hard to check on a 250 with direct injection...and I wouldn't suggest you try either.
Do you think the EVAP system could be a factor? I’m not sure if the EVAP operates while idling in park or only while in gear
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Old Jan 26, 2019 | 07:16 PM
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Originally Posted by pngo
Do you think the EVAP system could be a factor? I’m not sure if the EVAP operates while idling in park or only while in gear
The EVAP system won't operate when it's cold, the OP has this issue at startup.
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Old Jan 27, 2019 | 06:30 PM
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Originally Posted by Sasnuke
The EVAP system won't operate when it's cold, the OP has this issue at startup.
Just curious, when does the EVAP system work? Only while in gear at higher RPMs? Or any time as long as the system is warm?
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Old Jan 27, 2019 | 08:06 PM
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The ECU determines when to purge the vapor in the canister back into the engine.
The vehicle needs to be at operating temperature at least an not at idle (so driving). There are other parameters beyond that, but those are the basics.
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Old Mar 13, 2019 | 12:24 AM
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I got a video of it. Anyone seen this before?
https://youtu.be/37cCGojNqxI
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Old Mar 13, 2019 | 06:47 AM
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Originally Posted by Sonn
I got a video of it. Anyone seen this before?
https://youtu.be/37cCGojNqxI
If the dashboard lights are actually reacting like how they are in the video, it looks like you have an electrical connection issue.
First i would check both terminals on the battery...make sure they are clean and tight.
I would go so far as to remove them both, clean the posts on the battery and the interior of the terminal where it sits on the posts, and then reassemble everything making sure they are seated all the way down and they are tight.

Did the vehicle have any electrical repairs recently? Or does it have any aftermarket electrical accessories? (like an alarm, or remote start, or anything like that)
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Old Mar 13, 2019 | 03:00 PM
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Originally Posted by Sasnuke
If the dashboard lights are actually reacting like how they are in the video, it looks like you have an electrical connection issue.
First i would check both terminals on the battery...make sure they are clean and tight.
I would go so far as to remove them both, clean the posts on the battery and the interior of the terminal where it sits on the posts, and then reassemble everything making sure they are seated all the way down and they are tight.

Did the vehicle have any electrical repairs recently? Or does it have any aftermarket electrical accessories? (like an alarm, or remote start, or anything like that)
No after market at all. All original. I'm experiencing car shutdown at low rpm and having delay when low rpm when I push the acceleration, usually like 2 secs or 4.
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Old Mar 13, 2019 | 03:54 PM
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Does this happen every single time? Are you able to drive it normally at all?
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Old Mar 13, 2019 | 04:05 PM
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Originally Posted by Sonn
No after market at all. All original. I'm experiencing car shutdown at low rpm and having delay when low rpm when I push the acceleration, usually like 2 secs or 4.
Check the battery connection first.
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