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My girlfriend just bought a demo Cruze from a dealer with 6400km on it. 2 hours into our drive home from the dealership I noticed that the car was revving at about 3200-3300rpm which i thought was high. I was traveling at 120kmph btw, and i figure it should be at roughly 2600-2700rpm. so I slowed down to 110kmph and it was at 3000rpm. All traveling on a flat straight. It is winter here and being in Canada it was cold -3 degrees (27 fahrenheit), so just below freezing. I then put it into L and tried it manually. I dropped it 4 gear (revved high as normal), changed it to 5 gear (switched gears and lowered revs) then tried 6 gear and nothing (no change in rpm's). stayed at 3000rpm.

Brought it the dealership and they agreed after the test drive it didn't switch into 6th gear. After investigated it they said they found a form from GM head office that said some vehicles may experience the transmission not shifting into overdrive range during cold ambient temperatures. The conditions may be caused by the engine control system detecting conditions that indicate the freezing of moisture in the charge air cooler. I said that doesnt make sense after being on the road for 2 hours and everything is warmed up. He said it is the way it is programmed.

My question then if it's programmed that way then why is it only SOME and not most or ALL. My step daughter has the same vehicle in 2018 and it doesnt do it to hers. It sounds like to me an out so they don't have to replace it with a new transmission that is defective.

Has anyone experience the same problem and what has your dealership done about it? Do i have a defective transmission and travelling a high rpm's will it put strain on my transmission.

Thanks
Shayne
 

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I haven't noticed that at all on my 2017. But then again it's usually 10-15 minutes of city driving before I get to the highway so it's nice and warm by then.
 

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That’s
Not after 2 hours of driving. Sounds like it's a head ache they are trying to fluff off.

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that’s what it sounds like to me. on r the car heats up there should be no problems with shifting gears especially overdrive at 120kmph (75miles). the dealership I spoke to has sold hundreds of these cars and not 1 complaint. That tells me this is a problem. The dealership won’t back me and told me to go to the dealership I bought it from. That’s 2 hours away. Lol
 

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Discussion Starter #5
Not after 2 hours of driving. Sounds like it's a head ache they are trying to fluff off.

Sent from my SM-G935W8 using Tapatalk
I haven't noticed that at all on my 2017. But then again it's usually 10-15 minutes of city driving before I get to the highway so it's nice and warm by then.
ya so 2 hours on the highway doing 120kmph (75miles) it sure as hell should be switching.
 

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It is "Recommended" by the forum you read this. Seems relevant?

#29
11 hours ago
Resized_20200122_093005.jpeg

 

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Discussion Starter #7
ya so 2 hours on the highway doing 120kmph (75miles) it sure as hell should be switching.
It is "Recommended" by the forum you read this. Seems relevant?
#29 11 hours ago
Resized_20200122_093005.jpeg

thank you. I searched and search before I posted and I guess I missed that post.
 

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My girlfriend just bought a demo Cruze from a dealer with 6400km on it. 2 hours into our drive home from the dealership I noticed that the car was revving at about 3200-3300rpm which i thought was high. I was traveling at 120kmph btw, and i figure it should be at roughly 2600-2700rpm. so I slowed down to 110kmph and it was at 3000rpm. All traveling on a flat straight. It is winter here and being in Canada it was cold -3 degrees (27 fahrenheit), so just below freezing. I then put it into L and tried it manually. I dropped it 4 gear (revved high as normal), changed it to 5 gear (switched gears and lowered revs) then tried 6 gear and nothing (no change in rpm's). stayed at 3000rpm.

Brought it the dealership and they agreed after the test drive it didn't switch into 6th gear. After investigated it they said they found a form from GM head office that said some vehicles may experience the transmission not shifting into overdrive range during cold ambient temperatures. The conditions may be caused by the engine control system detecting conditions that indicate the freezing of moisture in the charge air cooler. I said that doesnt make sense after being on the road for 2 hours and everything is warmed up. He said it is the way it is programmed.

My question then if it's programmed that way then why is it only SOME and not most or ALL. My step daughter has the same vehicle in 2018 and it doesnt do it to hers. It sounds like to me an out so they don't have to replace it with a new transmission that is defective.

Has anyone experience the same problem and what has your dealership done about it? Do i have a defective transmission and travelling a high rpm's will it put strain on my transmission.

Thanks
Shayne
....
Im having same problems with my 19 cruze and they are telling me the same thing .. I am an autobudy tec and I know this is not normal ...they need to do something about this
 

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Block off the charge air cooler and see if that temporarily fixes the issue. Put a piece of cardboard on it with a couple zip ties or something like that.

Cold air going through the turbo is compressed and goes through some heating, but if it's really, REALLY cold it might still be subject to freezing temperatures when going through the intercooler if you have extreme cold ambient temperatures and enough airflow. Still, at something like 27ºF you wouldn't expect this problem.

If blocking off the intercooler fixes the problem, that likely means the temperature sensors are working because the air flowing through a blocked off intercooler shouldn't be below freezing.
 

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When the control system detects the above conditions and the ambient temperature is either below 0°C (32°F) or slightly above 0°C (32°F) with high moisture, but not frozen, it takes the following actions:
• Requests a lower gear than normal (resulting in higher RPM).
• The system will enable the condition as needed to prevent freezing.


I take back what I said above. You've found yourself in the exact correct set of circumstances where this TSB is applicable. Just speculation here, but you appear to have been driving in the exact set of circumstances to make this a prolonged problem: 27ºF and probably high moisture. This means the ECU is trying to prevent an icing condition in your charge air cooler, because the air going through the charge air cooler is loaded with moisture and is being chilled with lots of airflow at highway speeds.

Do a couple Google searches for "carburetor icing" to find out how this affects aircraft piston engines.

You could easily end up with a clogged intercooler if that moisture freezes up solid. The ECU is doing what it can to prevent this, by running the engine at a higher RPM so there is excess heat in the intake air from more boost.
 

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The only prior car I owned with something like this was a 1991 Subaru Legacy, and the transmission in that car was a 4-speed automatic with OD. The transmission would not engage overdrive until transmission fluid temperature was 60ºF or greater. During winter driving, there were some occasions I could start the car from cold and quickly get on the interstate, and the OD would not engage until the transmission fluid was heated up enough. There would be a noticeable THUNK as the OD would engage once it was warmed up enough.
 

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That’s


that’s what it sounds like to me. on r the car heats up there should be no problems with shifting gears especially overdrive at 120kmph (75miles).
Unless as a demo it's adapted to people driving it like demons by holding lower gears, it doesn't sound right to me.
When it's well below freezing, my 2016 won't shift into 6th for a while, sometimes as long as 5kms from my house. But if you drive long enough to get it warmed up, then either the transmission is overcooling or there's an electric/electronic problem.
 

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But if you drive long enough to get it warmed up
Warming the engine and/or transmission up has nothing to do with this. It's the ECU detecting temperatures below 32ºF (or slightly above) with high moisture levels. When you are driving in the right set of ambient conditions, you face the problem of having moisture freeze up the intercooler. The only way to combat this is to have the engine running fast enough to make more boost, to keep air flowing through the intercooler at a high enough temperature to not freeze up.
 

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So, here is one good question I thought about when I read this TSB: What does the ECU in the manual transmission cars do to prevent this condition?
 

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Basically driving at high rates of speed the cold air rushing in to the intercooler where there is hot air inside so it is creating condensation inside of the intercooler. The ecu Detects the condensation inside of the intercooler and also detects the temperature outside of the car with the Ambient temperature sensor. It is keeping it in 5 gear to prevent freezing inside of the intercooler. If you go 130 it will shift in to 6 and stay. This is 100% normal and is saving you from replacing your turbo and motor
 

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....
Im having same problems with my 19 cruze and they are telling me the same thing .. I am an autobudy tec and I know this is not normal ...they need to do something about this
Well...shows what you know then... ;)
It's normal. My 2018 does it about 50 miles into my commute typically when I'm on the highway at 68-70mph. Shifts down to 5th and runs at 3000rpm. It doesn't matter if you're in L6(which I usually am to disable autostop) or D, doesn't matter if you have cruise control on or not, doesn't matter if you slow down or coast...it tries to keep rpms up.

Now if when this happens when you have your cruise control on and the cruise disengages....that's a different issue and likely a sign of a problem, but this scenario will downshift with cruise on and in L6, and there will be no indication of anything wrong. Most people don't even notice it
 

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So, here is one good question I thought about when I read this TSB: What does the ECU in the manual transmission cars do to prevent this condition?
Nothing. It freezes. LOL
There's just a document for techs to look for frozen moisture in intercoolers and charge pipes on turbo cars with a P0299 set in cold weather.
 

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The ecu Detects the condensation inside of the intercooler and also detects the temperature outside of the car with the Ambient temperature sensor.
I'm not certain the vehicle is using the ambient temperature sensor for this. The ECU probably has temperature readings from the air flowing through one or more areas of the intake system.

Is there a MAF sensor, maybe a MAP sensor, and then one or more temperature sensors? I'd expect the engine to have at least one intake temperature sensor prior to the turbocharger, and one somewhere after the turbo; possibly two sensors after the turbo (one before the charge air cooler and one after the charge air cooler).
 

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Nothing. It freezes. LOL
Hah, nice!

Gasoline engines at moderate highway speeds are running very little boost because the engines are just loafing along, producing just enough power to keep a steady cruise speed. Gasoline engines can't increase boost much without adding more fuel, because the A/F ratio has to be at or near stoich for proper combustion and proper emissions treatment. Run more boost and you have to add more fuel, and that means the car would speed up instead of holding the steady speed.

With the diesel engine (with automatic or manual transmission), there is probably the ability of the ECU to increase boost. Diesel engines always run lean on fuel, so increasing the air going into the cylinder doesn't do anything to increase power... but by increasing boost it does increase the temperature of the air flowing through the charge air cooler to where it can keep it from freezing.
 
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