The most common cause that will trigger the P1320 code is the ignition coils, one or more ignition coils may have failed. Even tough the coils may be working OK, the resistance for one or more of the coils is greater or smaller that what the Engine Control Module (ECM) is expecting. Measuring the resistance with the coil out of the vehicle may not show any failures, usually the coil fails under heavy conditions (hard acceleration) or certain temperatures.
The P1320 code means that there is problem with the "Ignition Coil" or the wire to the ignition coil. For some models without individual ignition coils the Ignition Coil is inside the distributor and the distributor need to be replaced to fix the problem.
When the ignition signal in the primary circuit is not sent to Engine Control Module (ECM) during engine cranking or running.
Engine Light ON (or Service Engine Soon Warning Light)
P1320 Nissan Description
The ignition signal from the Engine Control Module (ECM) is sent to and amplified by the power transistor. The power transistor turns on and off the ignition coil primary circuit. This on-off operation induces the proper high voltage in the coil secondary circuit.