GM Gen3 P/N Switch and VSS
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- Опубликовано: 22 авг 2024
- Explanation of GM Gen3 idle routine and why it's necessary to wire up a park/neutral switch to the PCM along with a VSS sensor.
To enable go to system settings in hptuners and set the range select to "PN". This will enable the Blue Pin34 to monitor PN status. Ground=Park/Neutral / Open=In-Gear
VSS Wiring is Red or Green connector (Red for P01, Green for P59) Pin 20 and 21. Pin 20 is the low side signal and Pin 21 is the high side signal from the VSS of the transmission or a 2 wire ABS sensor.
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this explains the whole issue im having on my 24x swapped big cam LT1 with a turbo 400, thank you man
I recently swapped a 5 speed behind my gen3 5.3 and it doesn't have a vss. I am thinking about hooking the factory vss sensor up to a tone ring on the driveshaft. do you know if the factory GM vss from the 4l60e is a 12v or 5v signal output? also, do you know if I need to use magnets on my driveshaft for the sensor to pick up a signal, or if it will pick up a signal from the U-joint passing by? I know I can adjust the tune for the different pulse count, I just can't seem to find any info about a DIY vss setup. thanks!
I have a gen 3 - 5.3 with a 700r4 and have a high idle when start up and same times at a stop light. With ground the pin 34 , will help my problem.
What pin on the pcm should the vss signal go to? Thanks for any info.
All info is in the description.
Great info dude! Its hard to find this stuff. Im struggling to get my Gen3 VSS to work on my 231j t-case. Any suggestions on a cure 🤔 ?
The factory PCM looks for a VR signal so whatever you use needs to send that type of signal. You can input the tooth count in the tune then back calculate the pulse per mile and trans rev/mile information.
Question for you. I have a ls 5.3 attached to a manual 6 speed porsche transaxle. Should i still wire in a VSS? I made provisions to the pcm but have not figured out a VSS setup yet. Any help is greatly appreciated. Thank you
Yes it will make idle routine work much more like stock. With no VSS signal the PCM thinks your vehicle is sitting still all the time. This is a problem because under a predefined speed the PCM goes into closed loop idle routine to actively track target idle speed. This is especially troublesome on manual transmissions due to engine braking in gear off the throttle. When TPS goes to 0% and VSS is at 0mph closed loop idle is enabled. If the car is coasting down the road in gear the momentum is mechanically holding engine RPM higher than target idle which will cause the IAC system to close attempting to slow the engine down.
@@ShorTuning Thank You! that was exactly what i needed to know.
James, I have a question for you...I’m running an LS swapped Colorado (5.3/4L60E combo). My transmission will intermittently drop out of 4th gear, and then after a mile or so will shift back into 4th. It seems to start acting funny after it warms up-after driving 20 miles or so. Is there something in the tune that could be causing this, or is more likely something in the trans itself? Thanks!
Sorry just now seeing this. More than likely it's something in the transmission or may be a safety table we don't have access to pertaining to a temperature or slip issue within the trans. Be sure your up/down shift patters aren't overlapping confusing the ECU.
did you ever figure this out I have similar issue rebuilt transmission with no sucess obd live shows speedometer jumping up and down during constant speeds and suspect a bad vss sensor
So where should the pin wire34 be connected?
Thanks
To the Park/Neutral switch most shifters have built in.
@@ShorTuningwill a psi standalone harness need the park/nuetral wire? It says it’s only for a t56 style trans I’m running a power glide to 5.3 gen3 will the vss control whether it’s in park or nuetral?