Low rmp shutoff.
01-26-19, 06:33 PM
#1
Driver
Thread Starter
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.
01-26-19, 06:41 PM
#2
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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?
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?
01-26-19, 06:46 PM
#3
Intermediate
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
01-26-19, 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.
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.
01-26-19, 07:00 PM
#5
Driver
Thread Starter
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
01-26-19, 07:13 PM
#6
Intermediate
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.
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.
01-26-19, 07:16 PM
#7
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01-27-19, 06:30 PM
#8
Intermediate
01-27-19, 08:06 PM
#9
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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.
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.
03-13-19, 06:47 AM
#11
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I got a video of it. Anyone seen this before?
https://youtu.be/37cCGojNqxI
https://youtu.be/37cCGojNqxI
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)
03-13-19, 03:00 PM
#12
Driver
Thread Starter
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)
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)
03-13-19, 03:54 PM
#13
Intermediate
Does this happen every single time? Are you able to drive it normally at all?
03-13-19, 04:05 PM
#14
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