Circuit/System Description

The boost gage is a measure of the engine manifold air pressure. The powertrain control module (PCM) sends a PWM signal to the boost gage via the boost gage signal circuit. The boost gage displays the engine air intake above and below the ambient manifold pressure. The PCM controls the engine boost pressure with the boost control solenoid. The engine boost system pumps more air than the engine would normally use into the intake manifold. The excess air pumped into the intake manifold, creates the engine boost effect. The maximum boost pressure is about 83 kPa (12 psi). When the ignition is turned ON and the boost gage is ON, the boost gage performs a power up self test as controlled by the PCM. The boost gage dial moves up to 0 kPa (0 psi) to indicate the boost gage passed the self test. Power is provided to the boost gage via the ignition 1 voltage circuit.