Help transmission won’t shift
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Help transmission won’t shift
I recently swapped my pcm in my 98 to the newer version. My car starts up and runs fine (finally it wouldn’t start before the swap). However, the car will not shift into third.
anything special o need to do with the tune? I made everything match my old settings in HP tuners. I have triple checked the pins and they are all correct.
anything special o need to do with the tune? I made everything match my old settings in HP tuners. I have triple checked the pins and they are all correct.
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Thread Starter
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1-2 shift seems to be working fine. I started with the tune that it loaded up when I read the new computer. I then changed it to match the old tune I had with the old computer. How do I tell if it is P01 or P59.
I will load up my tune this evening.
I will load up my tune this evening.
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My understanding is that you can't switch a manual tune into an auto tune by modifying the tables and scalars and flags. You have to segment swap the automatic transmission segment into the manual bin or simply start with an auto bin which is easier since they already exist.
P01 just refers to the 512k PCMs and P59 just refers to the 1M PCMs I believe.
P01 just refers to the 512k PCMs and P59 just refers to the 1M PCMs I believe.
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Last edited by Autotragic; Nov 3, 2020 at 09:14 PM.
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Try a partial first, I didn't change anything but trans parameters.
A couple things though, has the car been regeared and are you using stock tires sizes?
This does concern me a bit, if the speedo was working this would be easier but it might be two separate issues. The thing is though it is shifting 1-2 but not 2-3 and after looking through the tune file I think I know why but I want confirmation. This might be a I fixed this but now...kind of things. One thing at a time.
A couple things though, has the car been regeared and are you using stock tires sizes?
This does concern me a bit, if the speedo was working this would be easier but it might be two separate issues. The thing is though it is shifting 1-2 but not 2-3 and after looking through the tune file I think I know why but I want confirmation. This might be a I fixed this but now...kind of things. One thing at a time.
Last edited by Autotragic; Nov 3, 2020 at 10:17 PM.
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The PCM forces the transmission into 2nd gear when you manually put the shifter into 2nd, even at zero speed.
Will it shift from 1 to 2 as you accelerate if you have the shifter in drive or overdrive?
You have HP Tuners. Monitor the speed signal. Try forcing the gears.
Will it shift from 1 to 2 as you accelerate if you have the shifter in drive or overdrive?
You have HP Tuners. Monitor the speed signal. Try forcing the gears.
Last edited by lionelhutz; Nov 3, 2020 at 11:01 PM.
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The PCM forces the transmission into 2nd gear when you manually put the shifter into 2nd, even at zero speed.
Will it shift from 1 to 2 as you accelerate if you have the shifter in drive or overdrive?
You have HP Tuners. Monitor the speed signal. Try forcing the gears.
Will it shift from 1 to 2 as you accelerate if you have the shifter in drive or overdrive?
You have HP Tuners. Monitor the speed signal. Try forcing the gears.
I will monitor speed signal tomorrow. It did seem to shift from 1-2. At least when I first start up and go. It doesn’t seem to want to shift back down though.
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Still not shifting. I also replaced the VSS sensor and still no speedometer.
I am having the P0502 code now however.
I tried shifting manually and I can get it to shift between 1-2 only. Sometimes it doesn’t seem to want to shift back down very easily but it will shift between those two gears only.
I am having the P0502 code now however.
I tried shifting manually and I can get it to shift between 1-2 only. Sometimes it doesn’t seem to want to shift back down very easily but it will shift between those two gears only.
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So do you have a multimeter? Try checking for continuity if you're getting any signal across that sensor at all. If there is no continuity at all then you probably just have a broken wire somewhere.
of course finding where the wire is broken at might be a pain in the butt but you know you'll have something to go on.
of course finding where the wire is broken at might be a pain in the butt but you know you'll have something to go on.
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The PCM forces the transmission into 2nd gear when you manually put the shifter into 2nd, even at zero speed.
Will it shift from 1 to 2 as you accelerate if you have the shifter in drive or overdrive?
You have HP Tuners. Monitor the speed signal. Try forcing the gears.
Will it shift from 1 to 2 as you accelerate if you have the shifter in drive or overdrive?
You have HP Tuners. Monitor the speed signal. Try forcing the gears.
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Joined: Apr 2007
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From: South Western Ontario
Yes, something like that. It really does help starting from a stop in snow (not in a Corvette, but other vehicles).
As for the speedo, re-check the pinning of the speed sensor pins to ensure they go to the right place.
As for the speedo, re-check the pinning of the speed sensor pins to ensure they go to the right place.
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So I have replaced the VSS (same thing).
I have checked the lines from the VSS to the pcm they are good and send signal fine.
I had my ho tuner hooked up and can turn on all of the selenoids and can have the car go into every. Gear using go tuner to manual shift to each gear through the program.
the VSS does not show up on the ho tuner at all and no speed
so my thought is that the pcm is not reading the VSS signal.
it is either pinned wrong or could the pcm be bad as to the VSS only?
i have triple checked the pins. I have a 1998 corvette and the new pcm says it is out of a 2002. I have the VSS pins in the red numbers 20 and 21 (low signal and high signal).
any ideas?
I have checked the lines from the VSS to the pcm they are good and send signal fine.
I had my ho tuner hooked up and can turn on all of the selenoids and can have the car go into every. Gear using go tuner to manual shift to each gear through the program.
the VSS does not show up on the ho tuner at all and no speed
so my thought is that the pcm is not reading the VSS signal.
it is either pinned wrong or could the pcm be bad as to the VSS only?
i have triple checked the pins. I have a 1998 corvette and the new pcm says it is out of a 2002. I have the VSS pins in the red numbers 20 and 21 (low signal and high signal).
any ideas?