Note. For circuit reference, see the appropriate WIRING DIAGRAMS article. For connector and terminal identification, see CONNECTOR IDENTIFICATION .
Circuit Description
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 timing inputs is not being received by comparing 2 inputs.
The high and low resolution circuits toggle between 0.5-4.5 volts as camshaft turns. Following intermittent malfunctions to 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.
DTC will set when following conditions are present
- PCM detects a predetermined amount of high resolution pulses before detecting any low resolution pulses.