Pcm Code P012 - No Distributor (Tach) Signal: Action

PCM turns on SERVICE ENGINE SOON light.

NOTE: Test numbers refer to numbers on diagnostic chart.

This checks for proper output of ignition system. If voltmeter reads 0.5-2.8 volts, ignition control module is receiving pick-up coil signal and producing reference pulses.
This checks for proper ground connections between PCM and engine, and between PCM and ignition control module.
This checks for proper voltage through circuit No. 430 from ignition coil to PCM. If PCM terminal 1D8 sees 0.5-2.8 volts, PCM is receiving reference pulses.
If ignition system will produce spark, fault is not within pick-up coil or ignition control module.