PCM Controlled Tachometer Diagnosis
CIRCUIT DESCRIPTIONSchematic:
The tachometer signal is a Pulse Width Modulated (PWM) signal. The Instrument Panel Cluster (IPC) supplies ignition voltage to the tachometer control circuit through a pull-up resistor. The a low side driver in the PCM grounds the tachometer control circuit in relation to engine speed.
TEST DESCRIPTION
