Circuit Description

The ignition distributor supplies 2 timing inputs to PCM, a high resolution signal (180 pulses/crankshaft revolution) and a low resolution signal (4 pulses/crankshaft revolution). PCM can determine if one of the timing inputs is not being received by comparing the 2 inputs.

The high and low resolution circuits toggle between 0.5-4.5 volts as the camshaft turns. The following intermittent malfunctions to the low resolution circuit may cause DTC to set: an open in circuit, short to voltage, short to ground or a defective ignition module in distributor.