I have a 1998 Trans Am with a 1998 PCM. The trans is wired using the relay method. This is the only way I could get the car to shift. Now it’s shifting thru all the gears (not correctly) but I’m not getting any speedo.

On the HPtuners scanner I can see that the car is reading a speed.

The 4L80 has a VSS on it and I have the ICT billet pigtail for it with the red and blue wires. All I can find is for a 1999 and up PCM re-pin. Nothing on the 1998.

Do I need to pin this VSS to the computer? If so, which pins? I found the pin out for a 1998 PCM and I found Red connector - 71 - PPL - VSS low
Red connector - 7 - YEL - VSS signal return

I don’t want to start re-pinning stuff without knowing exactly what goes where.

any help is appreciated

 

Hmmm, if HPTuners is showing a speed, then the PCM must be reading the VSS. Is it the correct or almost correct speed?
Yes, on a 1998 PCM, the VSS is connected to pins 7 and 71 on the Red connector.
If the PCM is reading the correct speed, then I would expect the trans to shift correctly. If there were no VSS signal, the trans likely would just stay in 1st gear.