Problems connecting to PCM w/Autotap
Thread Starter
On The Tree
Joined: Mar 2003
Posts: 119
Likes: 0
From: Austin, Texas
Problems connecting to PCM w/Autotap I posted this in the conversions & hybrids section, but have not gotten much response.
I am almost finished with the LS1/T56 swap into my 96 Impala SS.
status web page
I used the 2001 LS1 harness and the 96 LT1 harness. I used the LT1 underhood fuses/relays/harness and mapped all of the wires from the LS1 harness. It cranks and my fuel pump comes on, but I get no spark and I am unable to connect with AutoTap to see what is going on. AutoTap is working fine (connected to another vehicle). I confirmed the wiring, BAT and GND at the DLC as well as checked the BAT, IGN and serial data connections at the PCM. I get nothing from AutoTap.
How can I confirm that my PCM is good (anyone near Austin, TX have one I can try or a car I can plug mine into)? Can a dealer test it on the bench?
I did plug my laptop into a 2002 Tahoo and it works fine, so it is not my laptop or cable.
Thanks for any help or suggestions.
Scott
I am almost finished with the LS1/T56 swap into my 96 Impala SS.
status web page
I used the 2001 LS1 harness and the 96 LT1 harness. I used the LT1 underhood fuses/relays/harness and mapped all of the wires from the LS1 harness. It cranks and my fuel pump comes on, but I get no spark and I am unable to connect with AutoTap to see what is going on. AutoTap is working fine (connected to another vehicle). I confirmed the wiring, BAT and GND at the DLC as well as checked the BAT, IGN and serial data connections at the PCM. I get nothing from AutoTap.
How can I confirm that my PCM is good (anyone near Austin, TX have one I can try or a car I can plug mine into)? Can a dealer test it on the bench?
I did plug my laptop into a 2002 Tahoo and it works fine, so it is not my laptop or cable.
Thanks for any help or suggestions.
Scott
Thread Starter
On The Tree
Joined: Mar 2003
Posts: 119
Likes: 0
From: Austin, Texas
Re: Problems connecting to PCM w/Autotap I know it is not the fuse as I have pulled the PCM and powered it on the bench as follows:
C1/C2 pins 1 and 40 > ground
C1 pin 19 > fused 12 volts with switch to simulate ignition switch
C1 pin 20 > fused 12 volts
C1 pin 57 > fused 12 volts
C1 pin 58 > serial data
I connected pins 4 and 5 on the DLC connector to ground, pin 2 to serial data and pin 16 to fused 12 volts.
Even with this very simplified “harness” I can not connect to the PCM.
The pin 16 provided power for the GM Tech 2. I am not sure if AutoTap or LS1Edit actually needs this power as the laptop has its own power, but I provided fused 12 volts on this pin anyway.
Thanks,
Scott
C1/C2 pins 1 and 40 > ground
C1 pin 19 > fused 12 volts with switch to simulate ignition switch
C1 pin 20 > fused 12 volts
C1 pin 57 > fused 12 volts
C1 pin 58 > serial data
I connected pins 4 and 5 on the DLC connector to ground, pin 2 to serial data and pin 16 to fused 12 volts.
Even with this very simplified “harness” I can not connect to the PCM.
The pin 16 provided power for the GM Tech 2. I am not sure if AutoTap or LS1Edit actually needs this power as the laptop has its own power, but I provided fused 12 volts on this pin anyway.
Thanks,
Scott
Thread Starter
On The Tree
Joined: Mar 2003
Posts: 119
Likes: 0
From: Austin, Texas
Re: Problems connecting to PCM w/Autotap Problem solved. The person I purchased the engine and trans from neglected to mention that the PCM was new and had never been flashed.
Thanks,
Scott
Thanks,
Scott
