You did not specify what engine, however that is a common problem in alot of those cars, you need to remove upper and lower intake manifolds to get to sensor. Refer to repair manual if you do not have auto repair experience (and understand directions), it may be found at library or bought at parts store.
Crankshaft position sensor circuit malfunction.
Trouble code P0340 means:Camshaft position sensor circuit malfunction
Assuming you mean P0135, that would be O2 sensor heater circuit malfunction (bank 1 sensor 1). If the wiring to bank 1 sensor 1 is not damaged, it is probably a bad bank 1 sensor 1 O2 sensor. Replace it.
Trouble code P1320 means: Distributor Signal Interrupt
P0137 = O2 sensor circuit low volts (bank 1 sensor 2). Could be a faulty B1 S2 O2 sensor.
Heated oxygen sensor heater circuit malfunction (bank 1, sensor 1): Open or short in heated oxygen sensor heater circuit Heated oxygen sensor heater malfunction (Haynes Repair Manual)
Trouble code P0340 means:Camshaft position sensor circuit malfunction
Camshaft position sensor circuit malfunction.Camshaft position sensor circuit malfunction.
It is O2 Sensor Circuit Malfunction possibly (bank 2 Sensor 2) Yogi karki It is O2 Sensor Circuit Malfunction possibly (bank 2 Sensor 2) Yogi karki
P0130 = O2 sensor circuit malfunction (bank 1 sensor 1) P0150 = O2 sensor circuit malfunction (bank 2 sensor 1)
Firstly, you'll need to identify what's wrong with the sensor. If the circuitry is problematic, you'll need to replace part of the circuit to get it working well again.
O2 sensor circuit malfunction (bank1 sensor 2)
You can find a 1996 Nissan Pathfinder knock sensor picture in most auto repair manuals. Most Nissan dealerships repair centers will provide you with a picture of the sensor.
O2 sensor heater circuit malfunction, Bank 1 Sensor 1.
O2 sensor circuit malfunction (sensor 1). I got this directly out of the Haynes Repair Manual, so I personally suggest you replace your Oxygen sensors.
P0130 = 02 sensor circuit malfunction (bank 1 sensor 1)
P0706 = Transmission Range Sensor Circuit Range/Performance P0705 = Transmission Range Sensor Circuit Malfunction (PRNDL input)