Truck is a 96 S10 Extended cab, originally a 4.3 Vin X 5 speed, Z85 suspension, non ZQ8 with factory 8.5 rear axle. We have swapped in a 408LSx T56 using a Current Performance harness and have removed the ABS entirely so the stock ECM is no longer around.

The truck is running and driving, no CEL, i have power and ground at the OBD2 port and i have continuity between pin 59 on the ECM and pin 2 on the OBD2 connector. With the harness connector installed into the ECM, i also have continuity to pins 4 & 5 on the OBD2 port which are chassis and system grounds respectively, and also pin 8 which is CCM diagnostic. With the ECM plug removed from the ECM i only have continuity to between pin 59 and pin 2.

My question is, would this be considered normal. Ive gone as far as cutting the harness wire at pin 59 and pin 2 and connecting a jumper wire between the two completely bypassing the wiring harness altogether and i am still not able to get serial data on pin 2.

I removed the dash to replace the heater core, and in the process of putting everything back together there is a junction block on the passenger side of the dash behind the glove box, one of the wires got pinched between it and the metal mounting bracket, when i first hooked up the battery to try and start the truck one of the fusible links on the drivers fender junction block blew. I wasn't sure what this link controlled since they aren't labeled, but the truck cranked over but wouldn't start. I had no power to the fuel pump or ECM, i applied power to the fuel pump bypass plug and it powered up just fine but still wouldn't start. After a few days of retracing my steps i found the pinched wire, fixed it, replaced the fusible link and the truck fired right up. But its not running to great since the tune isn't 100%.

As far as can tell the pinched wire didn't cause any other problems, but im wondering if it somehow is the cause of us now not being able to link to the ECM thru the OBD2 port. With the ECM out of the truck and on the bench, Nelson can connect to it just fine.

If i cant come up with some options to check, or somebody that has maybe had this problem before im going to have to remove the harness and send it back to Current Performance for them to check it out. Something somewhere is blocking the data signal is what i think, cause if i have continuity on the circuit, i should have data connection as well.

Thoughts, Comments?

Thanks for any and all help.