Probe L4-121 2.0L DOHC VIN A MFI (1993)
Power Steering Pressure Switch: Description and Operation
With Manual Transmission
Power Steering Pressure Switch
PURPOSE
The Power Steering Pressure (PSP) switch sends an input signal to the Powertrain Control Module (PCM) when the power steering pressure rises
above 400-600 psi. The PCM uses this signal to adjust idle speed to compensate for additional load on the engine.
OPERATION
The normally open PSP switch receives a 5.0 volt reference signal from the PCM. When the power steering is engaged the switch shuts and the
PSP circuit drops to 0.0 volts as the reference signal is shunted to ground along the SIG RTN circuit.
RELATED DIAGNOSTIC TROUBLE CODES
DTC 519 - PSP circuit shut during the Key On Engine Off (KOEO) self-test.
DTC 521 - PSP circuit did not change states during the Key On Engine Running (KOER) self-test.
