Principles of Operation

Principles of Operation

Hydraulic Brakes

To diagnose hydraulic brake concerns, refer to Brake System - General Information Testing and Inspection.

Adjustable Pedals Without Memory Feature

The adjustable pedals without memory feature are controlled by the adjustable pedal switch and the Steering Column Control Module (SCCM). The adjustable pedal motor is attached to the accelerator pedal bracket and controls the accelerator pedal directly. The adjustable brake pedal is connected to the motor by a cable that rotates inside a sleeve. This allows both the brake and accelerator pedals to move together as an assembly. When the adjustable pedal switch is pressed, voltage is sent from the SCCM to the motor. The adjustable pedal motor operates in both directions, forward and rearward, depending on which direction the switch is pressed. The end of the motor that is attached to the accelerator pedal bracket rotates the pinion of a worm gear set and causes the accelerator pedal to move. At the same time, the other end of the motor rotates the cable inside the sleeve which causes the brake pedal adjuster to move through the use of a worm gear set. The pedals can be adjusted with the ignition switch in the OFF, ACC or RUN position, regardless of transmission shift lever position.

The SCCM continually monitors the adjustable pedal motor and circuits. If an error is detected, the SCCM is capable of setting DTCs.

Adjustable Pedals With Memory Feature

The adjustable pedals with memory feature are controlled by the SCCM and the Driver Seat Module (DSM) and can be adjusted in 3 different ways:

- Using the adjustable pedal switch.
- Using the memory SET switch.
- Using the Remote Keyless Entry (RKE) transmitter.

When the adjustable pedal switch is pressed, the SCCM sends voltage to the adjustable pedal motor, and the adjustable pedal motor operates in either direction, forward or rearward, depending on which direction the switch is pressed. The end of the motor that is attached to the accelerator pedal bracket rotates the pinion of a worm gear set and causes the accelerator pedal to move. At the same time, the other end of the motor rotates the cable inside the sleeve which causes the brake pedal adjuster to move through the use of a worm gear set. The pedals can be adjusted from the adjustable pedal switch with the ignition switch in the OFF, ACC or RUN positions, regardless of transmission shift lever position.

When the RKE transmitter is activated, a message is sent over the Medium Speed Controller Area Network (MS-CAN) bus to the DSM. When the memory SET switch is pressed, the Driver Seat Module (DSM) senses continuity to ground on the switch circuit. When the DSM receives either the MS-CAN message or the ground input through the switch circuit, it sends a message over the MS-CAN bus to the Body Control Module (BCM). The BCM acts as a gateway module, relaying the MS-CAN message that was received from the DSM to the SCCM over the High Speed Controller Area Network (HS-CAN) bus. The SCCM then sends voltage over the appropriate circuit to the adjustable pedal motor, and the adjustable pedal motor operates the same as when the adjustable pedal switch is used. The SCCM monitors pedal position using a Hall-effect switch that is built into the pedal motor. The pedal positions remain in memory as long as the DSM retains power. When a memory position is recalled through either the memory SET switch or the RKE transmitter, the SCCM monitors the Hall-effect switch and stops sending voltage to the pedal motor once the commanded memory position is reached. If the SCCM receives a pedal position input from the adjustable pedal switch during a memory position recall function, the module stops the memory recall and responds to the new pedal position input. The pedals can be adjusted from the memory SET switch or the RKE transmitter with the ignition in RUN, but the transmission must be in the PARK or NEUTRAL position. If the ignition is OFF or in ACC, the pedals can be adjusted from the memory SET switch or the RKE transmitter with the transmission shift lever in any position.

The DSM also controls the driver seat and the exterior mirrors.

The SCCM continually monitors the adjustable pedal motor and circuits. If an error is detected, the SCCM is capable of setting DTCs.

For information on setting and recalling a memory pedal position, refer to Memory Position Programming in Seating Programming and Relearning.