Power Steering Control Module (PSCM)
| ITEM | DESCRIPTION |
|---|---|
| 1 | Diaphragm |
| 2 | Power Steering Control Module (PSCM) |
| 3 | Electric motor power supply connector |
| 4 | Torque sensor connector |
| 5 | Electrical connection to vehicle systems |
The PSCM is located on the end of the electric motor, under a hermetically sealed cover. A diaphragm in the cover, made from a waterproof breathable fabric, maintains the interior of the cover at ambient pressure, avoiding the need for an open vent.
As well as the control circuitry, the PSCM also contains the power electronics for operating the electric motor.
Power assistance is provided when the following are present:
- Ignition feed from the ignition relay in the Central Junction Box (CJB).
- The engine is running.
Electrical power for operation of the electric motor is provided by a permanent power feed from the Battery Junction Box (BJB). For 100% nominal power assistance, supply voltage must be between 10.5 and 18 V. If supply voltage is outside of these limits, power assistance is either reduced or discontinued.
The PSCM receives digital inputs from the torque sensor via hardwired connection and messages on the HS (High Speed) CAN (Controller Area Network) chassis systems bus from the following:
- Steering angle from the SASM
- Engine speed, from the Engine Control Module (ECM), via the Gateway Module (GWM).
Refer to Electronic Engine Controls (Description and Operation).
- Vehicle speed and yaw rate, from the Anti-lock Brake System (ABS) control module.
Refer to Anti-Lock Control - Stability Assist (Description and Operation).
- Automatic steering requests, from the Parking Aid Control Module (PACM) (if park assist system is fitted).
Refer to Parking Aid (Description and Operation).
- Reverse gear signal from the CJB, through the GWM (manual transmission only).
- Vehicle speed from the Transmission Control Module (TCM), through the GWM (automatic transmission only).
Refer to Transmission Description (Description and Operation).
- Power mode from the CJB via the GWM.
- Eco stop/start system stop request from the ECM, through the GWM (if stop/start system is fitted).
Refer to Starting System (Description and Operation).
The PSCM uses the input data and software algorithms to control electric motor operation. If required, the PSCM can also transmit outputs, on the HS CAN chassis systems bus, of
- Warning status, to the Instrument Cluster (IC) through the GWM
- Eco stop/start system inhibits requests to the ECM through the GWM