programming and scanning an E37 or E38 outside of vehicle.

[samgm2]

I am writing software interfacing our dyno to the V2 and it would be very convenient if I could test the software at my desk (where my development environment is) then at the vehicle (which is a pain in the #$&&#@). Does anyone know if this is possible.

I tried connecting power, ground and data lines and no go.


Connections as follows (on cut pigtails from a junk yard harness from a Cobalt):

X1 (J1) cable

Pin 3 (X1, Accessory Voltage), 20 (X1, Battery Positive Voltage), 19(X1, Ignition 1 Voltage) to +12 V on power supply to the +12 pin on the diagnostic connector
Pin 7(X1 - ohm'd to signal gnd on X2) to the gnd on the supply, to gnd on the diagnostic connector
Pin 43 (X1, High speed GMLan +) on the X1 cable to + data on the diagnostic connector
Pin 44 (X1, High speed GMLan -) on the X1 cable to the - data on the diagnostic connector.

The software seems to scan as if the ecm is there but I don't get data.
More importantly, I am unable to read the flash on the PCM.

Anything obvious here?

[GMPX]

Compare to THIS.