Rear FD 3.54 Problem!!! (P1574)
#1
01-24-2011, 10:05 AM
Rear FD 3.54 Problem!!! (P1574)
Ok I recently changed my Diff to a manual g35 2005 3.54. Now my car is throwing a code of P1574. I did a little research on this code it has something to do with a speed sensor or something like that has any other 3.54 pumkin swap drivers out there had this issue before? I have a 2003 g35 Sedan
#2
01-24-2011, 11:47 AM
Ok I recently changed my Diff to a manual g35 2005 3.54. Now my car is throwing a code of P1574. I did a little research on this code it has something to do with a speed sensor or something like that has any other 3.54 pumkin swap drivers out there had this issue before? I have a 2003 g35 Sedan
#3
01-24-2011, 12:11 PM
#4
01-24-2011, 12:49 PM
What are the exact sizes? If the tire's vary in overall height by a significant amount, it can flake out the speed sensor(s). The 3.54 gear already puts the speed sensor readings very close to the point of flaking out. I believe OCG35 has had this issue before, but is merely a nussiance code that comes and goes. Driveability is unaffected.
#6
01-24-2011, 03:26 PM
That's probably it. The front tires are about .8" shorter than the rears. Paired with 3.54 gears, the speed sensor is probably just out of range, especially if you do a lot of higher speed driving. When spring comes around, I'm doing 225/45R18s in the front and 245/40R18 in the back because the size match up to within .1". I never understood why the Z and G coupe with 18s had such a taller out back.
#7
01-24-2011, 03:32 PM
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#9
01-25-2011, 09:58 AM
What are the exact sizes? If the tire's vary in overall height by a significant amount, it can flake out the speed sensor(s). The 3.54 gear already puts the speed sensor readings very close to the point of flaking out. I believe OCG35 has had this issue before, but is merely a nussiance code that comes and goes. Driveability is unaffected.
#10
01-25-2011, 10:09 AM
Join Date: Apr 2009
Location: Tallahassee, FL (or thereabout)
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I'm not entirely sure you completely get the concept of gear ratios.
Starting at the engine, it's rotational motion goes through several different reduction ratios before becoming linear motion (the car moving forward)
First at the transmission (depending on what gear you're in)
Second at the rearend (which you've changed to be a different ratio)
And then finally (this one's important to) at the tires.
Changing the overall diameter of your rear tires is similar (though not quite as dramatic) as changing your FD ratio.
A smaller diameter tire shifts the true "final" ratio in the same direction as when you swapped from a 3.33 to a 3.54
So really, you're even more than a 3.54 so to speak.
On a lot of older cars, it's not much of an issue. But the G keeps track of every single one of those ratios, and if any single one, or several, get out of spec far enough, it starts throwing codes.
Starting at the engine, it's rotational motion goes through several different reduction ratios before becoming linear motion (the car moving forward)
First at the transmission (depending on what gear you're in)
Second at the rearend (which you've changed to be a different ratio)
And then finally (this one's important to) at the tires.
Changing the overall diameter of your rear tires is similar (though not quite as dramatic) as changing your FD ratio.
A smaller diameter tire shifts the true "final" ratio in the same direction as when you swapped from a 3.33 to a 3.54
So really, you're even more than a 3.54 so to speak.
On a lot of older cars, it's not much of an issue. But the G keeps track of every single one of those ratios, and if any single one, or several, get out of spec far enough, it starts throwing codes.
#11
01-25-2011, 10:16 AM
I'm not entirely sure you completely get the concept of gear ratios.
Starting at the engine, it's rotational motion goes through several different reduction ratios before becoming linear motion (the car moving forward)
First at the transmission (depending on what gear you're in)
Second at the rearend (which you've changed to be a different ratio)
And then finally (this one's important to) at the tires.
Changing the overall diameter of your rear tires is similar (though not quite as dramatic) as changing your FD ratio.
A smaller diameter tire shifts the true "final" ratio in the same direction as when you swapped from a 3.33 to a 3.54
So really, you're even more than a 3.54 so to speak.
On a lot of older cars, it's not much of an issue. But the G keeps track of every single one of those ratios, and if any single one, or several, get out of spec far enough, it starts throwing codes.
Starting at the engine, it's rotational motion goes through several different reduction ratios before becoming linear motion (the car moving forward)
First at the transmission (depending on what gear you're in)
Second at the rearend (which you've changed to be a different ratio)
And then finally (this one's important to) at the tires.
Changing the overall diameter of your rear tires is similar (though not quite as dramatic) as changing your FD ratio.
A smaller diameter tire shifts the true "final" ratio in the same direction as when you swapped from a 3.33 to a 3.54
So really, you're even more than a 3.54 so to speak.
On a lot of older cars, it's not much of an issue. But the G keeps track of every single one of those ratios, and if any single one, or several, get out of spec far enough, it starts throwing codes.
Ok thanks, I have a much better understanding of the swap I did. Will i have to deal with this check engine light. Alot of people have done this swap. G35papa, Candlestickpark and a couple more that have slammed setups bigger and wider rims and tires. When i researched the swap i didnt see anything about cel light and any code issues. Should I just change the speed sensor or will the problem continue?
#12
01-25-2011, 10:22 AM
Join Date: Apr 2009
Location: Tallahassee, FL (or thereabout)
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Width of the rim and ride height make no difference. It's the overall diameter of the tire.
Also, the newer sedans (like CandlestickPark) react differently than the older ones like yours, mine and G35Papa's.
The problem could be your speed sensor, or might not be.
The issue is magnified by the speed you drive.
The faster you go, the more the difference is amplified.
Think of it like a tax percentage.
Tax on a candy bar is insignificant, but tax on a car is a large amount of money.
A small change in final drive ratio (or tire diameter) isn't much when you're going 35, but is a big difference at 90.
Also, the newer sedans (like CandlestickPark) react differently than the older ones like yours, mine and G35Papa's.
The problem could be your speed sensor, or might not be.
The issue is magnified by the speed you drive.
The faster you go, the more the difference is amplified.
Think of it like a tax percentage.
Tax on a candy bar is insignificant, but tax on a car is a large amount of money.
A small change in final drive ratio (or tire diameter) isn't much when you're going 35, but is a big difference at 90.
#13
01-25-2011, 10:34 AM
Width of the rim and ride height make no difference. It's the overall diameter of the tire.
Also, the newer sedans (like CandlestickPark) react differently than the older ones like yours, mine and G35Papa's.
The problem could be your speed sensor, or might not be.
The issue is magnified by the speed you drive.
The faster you go, the more the difference is amplified.
Think of it like a tax percentage.
Tax on a candy bar is insignificant, but tax on a car is a large amount of money.
A small change in final drive ratio (or tire diameter) isn't much when you're going 35, but is a big difference at 90.
Also, the newer sedans (like CandlestickPark) react differently than the older ones like yours, mine and G35Papa's.
The problem could be your speed sensor, or might not be.
The issue is magnified by the speed you drive.
The faster you go, the more the difference is amplified.
Think of it like a tax percentage.
Tax on a candy bar is insignificant, but tax on a car is a large amount of money.
A small change in final drive ratio (or tire diameter) isn't much when you're going 35, but is a big difference at 90.
Ok i understand, that explains sometimes on the highway i can set my cruise
control and sometime I can't. I would like someone that has my yr and the 3.54 and different tires to chime in. Not to say your not helping me or giving me a better understanding. Have your heard of this issue or anything to resolve this issue.
Also is the TCM which i think is the tranny cpu connected with that because my car gave a tcm code but later disappeared ????
#15
01-25-2011, 10:45 AM
