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Old 02-15-2020, 01:16 AM   #1
Superchargedk20
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Default Boost cut?

Hey guys this never has happened to me before. Today was driving my 2018 sti on the highway and gave it a little boost in 6th gear. The car made a pop and hit boost cut. The VDC went into Sport mode and was flashing. Had a CEL on. Seemed to drive fine but I couldnt move the VDC. Got to work checked the codes and had " P0244 exceeded boost limited" and U0122 "lost communication with VDC". When I got to work I reset the codes. I shut the car off and it had a difficult time starting. It wouldnt turn on the first try. I waited a few seconds and it started up and seemed to run fine and I was able to turn the VDC again. I'm just curious if you hit boost cut does the car automatically throw the VDC as a safety precaution? My car is tuned so that Sport sharp is the highest boost setting. So idk if locking it to sport mode is a safety feature? I also had a car starter recently installed , but that also has never given me any issues.
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Old 02-15-2020, 01:39 AM   #2
9521Cody
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Boost in 6th gear at highway speeds is low rpm high load. This causes overboost which threw your PO244 code. Donít do this. Itís not good for your engine at all. If you need to pass downshift to 5th for a little pick up, and down to 4th if you need more. Never mash the throttle in 5th or 6th. Your car had a hard time starting because you reset the code. This clears all ecu learning parameters.
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Old 02-15-2020, 05:04 AM   #3
Superchargedk20
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Originally Posted by 9521Cody View Post
Boost in 6th gear at highway speeds is low rpm high load. This causes overboost which threw your PO244 code. Donít do this. Itís not good for your engine at all. If you need to pass downshift to 5th for a little pick up, and down to 4th if you need more. Never mash the throttle in 5th or 6th. Your car had a hard time starting because you reset the code. This clears all ecu learning parameters.
Thanks man. Does this caus the VDC code as well? Kind of like a limp mode?
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Old 02-15-2020, 04:32 PM   #4
9521Cody
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Quote:
Originally Posted by Superchargedk20 View Post
Thanks man. Does this caus the VDC code as well? Kind of like a limp mode?


Yes this will cause the VDC light to illuminate. In a WRX it will appear as the Traction Control Light and the Cruise light will flash. Same thing, just an indicator you did something your car did not like. If you have to clear codes, the best way to start your car easily after is to turn the ignition to the ON position for 30 seconds before trying to crank it. I did a lot of hard learning on my old car just like you.
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Old 02-16-2020, 03:21 AM   #5
some dude
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A common rule as stated above: don't give lots of throttle in 6th gear, it's bad for the engine.
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Old 02-16-2020, 08:51 AM   #6
Superchargedk20
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Yes this will cause the VDC light to illuminate. In a WRX it will appear as the Traction Control Light and the Cruise light will flash. Same thing, just an indicator you did something your car did not like. If you have to clear codes, the best way to start your car easily after is to turn the ignition to the ON position for 30 seconds before trying to crank it. I did a lot of hard learning on my old car just like you.
Thanks man this is my first subie so still trying to understand some stuff. My evo is alot easier to manage lol.
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Old 02-16-2020, 08:59 AM   #7
Jay11STI
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I would highly recommend you not lugg the engine. High gear, high load, low rpm is a recipe for diaster on these cars. Its been covered alot throughout the years. Like others have recommended, if your going to try and make power, down shift as much as possible. I personally try and avoid boost in 5th and 6th unless i started making power in a lower gears like 4th and below.
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Old 02-16-2020, 09:02 AM   #8
Superchargedk20
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I would highly recommend you not lugg the engine. High gear, high load, low rpm is a recipe for diaster on these cars. Its been covered alot throughout the years. Like others have recommended, if your going to try and make power, down shift as much as possible. I personally try and avoid boost in 5th and 6th unless i started making power in a lower gears like 4th and below.
Yea def. It was only a part throttle push at like 80 mph. But it was ridiculously cold out. It hit 23.30 psi. Didnt like that.
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