Hello Jk and welcome to Just answer.com, Super mechanic here. About your Jimmy.
The trouble code, (P0147) is an indication that there is a malfunction in the 02 sensor heater control for the bank 1 sensor 3 exhaust oxygen sensor circuit.
That is the 02 sensor that will be in the rear of the catalytic converter. You will want to check the wires that go to it first and make sure there is a good connection there. If the wires are clean and tight then the sensor is most likely at fault. They are fairly simple to replace and they are available after market for about $50.