PSoC opamp output range is from 0.2-VDDA( or 0.5 to VDDA in high power mode). The instrumentation amplifier configuration you use needs the opamp output to go to negative voltage range(when the negative input is grounded) which is not supported by the device. You may need the psoc ground to be at a lesser voltage than the shunt ground for the instrumentation amplifier to work.
Thank you for getting back to me ... I will switch this measurement to a current shunt monitor with a large common mode (-14V to 80V) voltage range that can run from a single supply. This will also allow me to move sense resistor to high side so i can detect a short to ground.
Thanks again for your help