kur4o wrote:I am sure these performance modes are triggered by external switches. We need to locate the pins that are being used for this. 2nd gear start and performance might use the same pin, but 4wd low will be definitely another pin. Than we can manipulate the command logic. I think some might be mutually exclusive via software settings. There might be other input/output pins left on board, paired with AD channels and PWM channels. Some hardware tracing will be needed, to fully exploit the p04 pcm.
A good indicator is to measure each pin for resistance to ground. When pcm is powered to measure voltage to ground and voltage to B+. Some analysis after that can reveal similar channels, and matching that with existing data sheets can spot quickly some of the unused pins capabilities. Last some board tracing and finding patterns of RC networks.
The only "4WD" p04 vehicles I'm aware of are the Venture/Montana vans, which are more of a part time AWD than true 4WD. I don't think it has 4High/4Low and techline seems to confirm this.
Maybe there are other 4wd applications that could explain it though
ProfessWRX wrote:Any chance you guys have a pinout for the 04 L67 Pcm? I haven’t seen one.
I'm always hoping that the pinout will make sense against input registers, but this one doesn't give me any hints.
I did find quite a few dead inputs that are read. But I'm no hardware man. Finding the corresponding pins on the PCM itself is a bit too much for me right now. I'll do what I can.
I think I found the CPU register for some inputs in the logic. I saw them before but never traced them. It's confusing code, but I'll get at it too just so I can understand exactly what's happening.
If you haven't seen it before, this post http://www.gearhead-efi.com/Fuel-Inject ... CM-pinouts is pretty helpful for seeing some of the various used/unused pins on different applications. It is missing the pin for the rear locker in the U vans, so I'm sure there are probably others still missing as well.
zack4200 wrote:If you haven't seen it before, this post http://www.gearhead-efi.com/Fuel-Inject ... CM-pinouts is pretty helpful for seeing some of the various used/unused pins on different applications. It is missing the pin for the rear locker in the U vans, so I'm sure there are probably others still missing as well.
I’ve seen it. I assume Kur4o has as well. What Kur4os trying to get done is mapping those outside pins to the registers in the code so we can make outside stuff talk to the pcm as we wish.
kur4o wrote:4WD_Lamp_On_Car -present/not present
Type_Of_Shift_Pattern - ???class2/pcm <--CPU control FFFF8FD9/FFFFC002
Shift_Patern_press_Time -time for switch pressed to activate
4WD_Switch - switch)type fitted <--7D514/7CFCB - Transmission Type/4WDSwitch
Trans type 4 and 2 are NOT 4WD allowed
4WD_press_Time -time for switch pressed to activate <--7CFAE - Debounce Time
kur4o wrote:Maybe trace where it get saved and monitor that value.
Found some 2nd gear switch that use the same logic as 4Low/tow and performance switches. Might give you good starting point to figure all the inputs, tracing the board.
It is from 2002 v6 firebird pcm
It would appear that this is the SAME schematic that I have in the GM SI database program!
