Pressure Switch

When hydraulic pressure reaches 3650 +/- 350 kPa (530 +/- 50 psi), the pressure switch of the power steering pump closes causing the Powertrain Control Module (PCM) to actuate the throttle valve, which increases the engine rpm to prevent the overload-induced engine speed slow down. The switch opens when hydraulic pressure drops to 3150 +/- 350 kPa (460 +/- 50 psi).