Help needed with Engine codes please.

Ok so I just picked up an '01, She runs like a champ so far, just a hole in muffler. Idiot light on, had codes read today, 6 came up.

-P1494 : Evap leak detection pump pressure switch condition
-P1491 : Radiator fan relay (fan comes on in acc)
-P0456 : Evap leak detected
-P0158 : Circuit condition
-P0135 : Heater condition
-P0161 : Heater condition

I'm guessing the last 2 are just o2, has anyone had any of the other ones before? Just don't want to go chasing problems if someone has had the same issue. The Jeep starts, idles and runs fine currently (minus the fan coming on early, Knock on wood) Thanks guys.

Test the O2 sensors. Inspect their wires and wire plugs for damage and/or corrosion. Check the O2 sensor fuses. It appears you have some front and rear O2 sensor short circuits or open circuits.

P0135 (M) 1/1 O2 Sensor Heater Failure. Oxygen sensor heater element malfunction.

P0158 (M) 2/2 O2 Sensor Shorted To Voltage. Oxygen sensor input voltage maintained above normal operating range.
Possible causes
- Rear Heated Oxygen Sensor Bank 2 harness is open or shorted
- Rear Heated Oxygen Sensor Bank 2 circuit poor electrical connection
- Faulty Rear Heated Oxygen Sensor Bank 2
- Inappropriate fuel pressure
- Faulty fuel injectors
- Intake air leaks
- Exhaust gas leaks

P0161 (M) 2/2 O2 Sensor Heater Failure. Oxygen sensor heater element malfunction.
Possible causes
- Rear Heated Oxygen Sensor Bank 2 harness is open or shorted
- Rear Heated Oxygen Sensor Bank 2 circuit poor electrical connection
- Faulty Rear Heated Oxygen Sensor Bank 2
- Inappropriate fuel pressure
- Faulty fuel injectors
- Intake air leaks
- Exhaust gas leaks

Check the Evap Leak Detection pump pressure switch, wire plug, wires, and vacuum tubing for damage or failure.

P1491 Rad Fan Control Relay Circuit. An open or shorted condition detected in the radiator fan control relay control circuit.

Replace the fan relay, check the fan wires, and wire plugs.