Principles of Operation

PRINCIPLES OF OPERATION

Power and Ground Requirements
The power requirements for the power sliding door (PSD) are 2 battery supply circuits to each PSD module. The smart junction box (SJB) fuse 11 (5A)supplies battery logic power required for the software and internal switching operations for both PSD modules. LH PSD motor, clutch and latch release actuator power is supplied by bussed electric center (BEC) fuse 16 (30A). RH PSD motor, clutch and latch release actuator power is supplied by BEC fuse 5 (30A).

Ground is a separate single connection for each PSD module. Some of the continuous inputs which are at a ground state when ON are also used for logic switching.

The ignition switch source is from the SJB fuse 13 (5A) for both PSD modules. The ignition power is used for diagnostic functions.

Combined PSD Detent and Latch Switch
The detent switch and the latch switch are contained in the latch assembly at the rear of the sliding door. The PSD latch switch works in parallel with the detent switch to identify the rear PSD latch position. The combined detent and latch input to the PSD module will be open circuit in PRIMARY LATCH position, and ground in SECONDARY LATCH or UNLATCHED positions. The PSD module determines latch state by the relationship between the combined detent and latch switch input and the C-pillar ajar switch input as follows:
- UNLATCHED
- Combined detent and latch switch provide a ground input to PSD module.
- C-pillar ajar switch provides a ground input to the PSD module.

- SECONDARY LATCH
- Combined detent and latch switch provide a ground input to PSD module.
- C-pillar ajar switch provides an open input to the PSD module.

- PRIMARY LATCH
- Combined detent and latch switch provide an open input to PSD module.
- C-pillar ajar switch provides an open input to the PSD module.

C-Pillar Ajar Switch
The C-pillar ajar switch is monitored by the PSD module to determine when the sliding door sheet metal is in proximity to the body sheet metal. The C-pillar ajar switch can be activated either before or after the latch is secured in SECONDARY position, depending on tolerances. During a PSD close operation, the PSD module monitors the C-pillar ajar switch for a state change (indicating secondary latch position) to turn off obstacle detection. The C-pillar ajar switch input is:
- an open circuit with the PSD closed.
- grounded with the PSD open.
- open circuit just before or at SECONDARY LATCH position (PSD partially latched).

Latch Release Actuator
Power is supplied to the release actuator by the PSD module when a valid open command is received. The actuator unlatches the PSD similar to manual activation of a door handle. The PSD module is unable to detect if the PSD is unlocked. If the PSD module is activated with the PSD locked, the latch release actuator will operate, but the PSD will not open.

Position Sensor
The PSD module supplies a 5-volt reference voltage to the position sensor on a valid open command or anytime the PSD is in the OPEN position up to 6 hours. The PSD module constantly supplies the ground. The position sensor has 2 data lines that the PSD module reads and tracks to determine the PSD movement and position. The PSD position is tracked so the PSD may be powered in the correct direction when a valid operation command is received. The velocity is tracked to identify obstructions and reverse the PSD operation if required.

Drive Assembly Actuator Clutch
The drive assembly actuator clutch separates the drive assembly actuator motor from the cable spool. This allows manual opening and closing of the PSD without driving the motor. The PSD module supplies power to the drive assembly actuator clutch for any valid operation command. The clutch connects the drive assembly actuator motor to the cable spool, allowing the motor to turn the spool and open or close the PSD.

Drive Assembly Actuator Motor
The drive assembly actuator motor is a reversible pulse width modulated motor. Upon a valid activation, the PSD module supplies power and ground to the motor circuits depending on the PSD position and the direction the PSD needs to be moved.

Overhead Console On/Off Switch
The overhead console on/off switch enables or disables the B-pillar switch, interior/exterior handle activation and power assist activation of the PSD. Both functions are enabled when the PSD module detects ground on the on/off switch circuit. With the overhead console on/off switch in the ON position:
- a ground signal is supplied to the PSD module.
- the B-pillar switches and interior/exterior handles are enabled.
- power assist is enabled.

The overhead console on/off switch has an ignition feed through the SJB fuse 16 (5A). With the ignition in RUN and the overhead console on/off switch in the ON position, the LED next to the switch will illuminate. With the on/off switch in the OFF position, the ground is removed and the B-pillar switches, interior/exterior door handles and power assist will not operate. The ground for the on/off switch assembly is shared by the overhead console open/close switches.

Overhead Console Open/Close Switch
Pressing the overhead console PSD open/close switch supplies a momentary ground signal to the SJB, which then unlocks the PSD if fully closed, and sends a signal to the corresponding PSD module to open or close depending on the conditions. The overhead console on/off switch does not affect the overhead console open/close switch.

B-Pillar Open/Close Switch
Pressing the B-pillar switch supplies a momentary ground signal to the corresponding PSD module. Upon receiving the input, the PSD module checks the overhead console on/off switch circuit for ground. If the circuit is at ground, the PSD module will open or close the PSD, if conditions are correct. If the on/off circuit is not at ground, the PSD module will ignore the input.

Remote Keyless Entry (RKE) Operation
The smart junction box (SJB) receives a PSD activation command from the remote keyless entry transmitter. The SJB will unlock the PSD only if the door is closed and then ground the open/close circuit to the appropriate PSD module. The remote keyless entry activation supplies a momentary ground signal to the appropriate PSD module commanding the PSD module to carry out an open or close operation, if conditions are correct. The signal and data transmitted between the SJB and the PSD modules is not specific to open or close operation. The PSD module will determine which operation to carry out depending on the PSD position when the signal is received.

SJB Interface
PSD open operation requires the vehicle to be in PARK and the vehicle speed to be less than 5 km/h (3 mph). The SJB receives information over the standard corporate protocol network (SCP) from the powertrain control module (PCM) for the PRNDL position and the anti-lock brake system/traction control module (ABS/TC) for the vehicle speed only when the ignition is in the ON position.

If the vehicle is in PARK, the SJB will ground the PARK (enable) circuit to the PSD modules. If the vehicle speed is less than 5 km/h (3 mph), the SJB will ground the vehicle speed circuit to the PSD modules. As long as these 2 circuits are at ground, normal PSD open operation can be carried out.

The SJB will prevent PSD open operation if either of these inputs are not grounded. These 2 inputs to the SJB have network DTCs. If either of these DTCs are retrieved and the PSD is not operating, repair these DTCs first.

PSD Operation
The following is a brief explanation of a normal power open cycle of the PSD.
- To begin the power open operation, the PSD module receives a momentary ground signal from the overhead console switch, RKE, interior/exterior door handle or the B-pillar switch. The PSD may also have been manually released with the interior or exterior sliding door handle.
- The PSD module checks the PARK and vehicle speed circuits from the SJB for ground.
- For the LH side PSD only, the PSD module checks the fuel filler door switch circuit for ground.
- The PSD module supplies power to the latch release actuator, which releases the PSD latch. Also, a 5-volt reference is supplied to the position sensor.
- The combined PSD detent switch and latch switch circuit is monitored for a ground signal indicating the rear latch is released.
- Power is supplied to the drive assembly actuator clutch and motor, opening the PSD.
- When the PSD is opening, the position sensor is monitored for the door position and velocity. If an obstruction is detected, the door will stop or reverse depending on the conditions.
- As the PSD is opened, the position sensor is used to track the PSD movement and position.
- The PSD FULL OPEN position is learned by the PSD module during the PSD initialization. When the PSD reaches the FULL OPEN position, the PSD module removes the power from the drive assembly actuator motor and clutch.

The following is a brief explanation of a normal power close cycle of the PSD.
- When the PSD module receives a close signal, power is supplied to the drive assembly actuator clutch and motor.
- As the PSD is powered closed, the position sensor is monitored for door position and velocity. The PSD will react if any obstruction is detected.
- The PSD module will then monitor the C-pillar ajar switch and combined detent switch and latch switch.
- When the PSD module receives input from the C-pillar switch, obstacle detection is turned off and full power is supplied to the drive assembly actuator motor to completely close and latch the PSD.
- When the PSD module receives input from the combined detent and latch switches indicating the PSD is in the PRIMARY LATCH position (PSD is fully latched), power is removed from the drive assembly actuator clutch and motor.

PSD Module Self-Test

WARNING: During the PSD self-test, the PSD will attempt to fully open and close the PSD. The PSD self-test does not require the PARK and vehicle speed sensor (VSS) signal to open the door. Do not carry out the PSD self-test with the vehicle in motion.

The PSD self-test will attempt to power open and close the PSD. As the PSD is opened and closed, the PSD module monitors the system for correct inputs. Upon completing the self-test, DTCs will be logged for any incorrect operations. The PSD module also checks the following inputs during a self-test:
- Overhead console ON/OFF switch circuit
- Overhead console open/close switch/RKE circuits
- B-pillar switch circuit
- C-pillar ajar switch circuit
- Combined detent switch and latch switch circuit
- PARK (enable) circuit from the SJB
- Vehicle speed circuit from SJB
- Fuel filler door circuit (LH PSD only)

The PSD module has the ability to reverse the PSD operation if certain conditions exist. This is a normal function of the system, however some electrical concerns may cause the same symptom. If the PSD reverses during operation or during the self-test, always check for an obstruction or misalignment first. If no obstruction or misalignment is found, make sure to complete all DTC and symptom diagnostics.

Initialization Procedure
If the PSD module loses the logic battery supply for any reason, such as battery disconnect, module disconnect or if left open for more than 6 hours, the PSD module will lose the PSD position stored in memory. Disconnecting the battery will cause both PSD modules to lose PSD position. Disconnecting the PSD module connector will only cause the specific module to lose its memory. If only one PSD module is affected, the initialization procedure only needs to be carried out for the specific module.

The PSD normal operation will not be restored until the PSD position is once again stored into memory. The initialization procedure is the learning process the PSD module uses to restore the PSD position in memory. The PSD module monitors the position sensor data received during the initial power open-and-close operation to learn the positions.

Refer to Power Sliding Door Initialization. Power Sliding Door Initialization