Power Folding Top
Power Folding Top Description and Operation
Overview
The operation of the convertible top is semi-automatic. The user of the vehicle manually latches and unlatches the convertible top while hydraulic power actuation provides the force to raise and lower the top.
The electrical portion of the power convertible top system consists of the following:
* Folding Top Control Module
* Header Latch Position Switch
* Folding Top Control Switch
* Luggage Barrier Sensor
* Folding Top Position Sensor
* Folding Top Pump Motor
Folding Top Control Module
The Folding Top Control Module (FTC) determines folding top movement by controlling the activation and direction of the hydraulic pump's electric motor based on hardwired inputs and vehicle status information it receives via low speed GMLAN. It also uses low speed GMLAN to interact with other sub-systems, communicate convertible top status and position, and interface with the driver via the Driver Information Center (DIC).
The Folding Top Control Module also contains an internal thermocouple which it uses to measure the outside ambient temperature in order to take its affect on the hydraulic fluid into account. This internal thermocouple is not accessible through a module pin to the outside world.
Switches and Sensors
Control Switches
The Folding Top Control Switch is a two-way rocker switch with center off, and is connected directly to the Folding Top Control Module. It contains two momentary contacts each providing a separate signal to the Folding Top Control Module. One provides the Folding Top Open Switch Signal and the other the Folding Top Close Switch Signal. Folding Top Control Module provides the switch with a referenced ground signal.
The Folding Top Control Module determines requested top operation by monitoring the two signals from the Folding Top Control Switch. Each signal input is recognized as active when the contacts in the Folding Top Control Switch complete the circuit path to the referenced ground signal. When either contact is inactive, the circuit is open and the signal circuit is pulled up to Battery by the Folding Top Control Module.
Folding Top Position Sensor
The Folding Top Position Sensor is a two-wire hall effect Sensor providing an input signal to the Folding Top Control Module indicating whether or not the top is fully retracted into its trunk storage area (Down) and properly stowed. The Folding Top Control Module supplies a switched filtered battery voltage to one terminal. The other terminal is a current source providing a signal to the Folding Top Control Module.
When the hydraulic cylinder is fully retracted, the top is down (open) and stowed. At this point the cylinder's piston is near the sensor which affects the sensor's internal magnetic field. The sensor's output current enters into the 2 to 5ma range and the sensor is considered active. As the cylinder extends and the top leaves the stowed position, the cylinder's piston moves away from the sensor changing its magnetic field back to its normal state. The sensor's output current enters into the 12 to 17ma range and the sensor is considered inactive.
Folding Top Luggage Barrier Sensor
The luggage barrier is a moveable shade used to divide the rear compartment into distinct sections. The luggage barrier contains a magnet in the stem that fits into the retainer slot containing the Folding Top Luggage Barrier Sensor. The Folding Top Luggage Barrier Sensor is sensitive to the presence or absence of the magnetic field produced by this magnet.
The Folding Top Luggage Barrier Sensor is a two-wire hall effect Sensor providing an input signal to the Folding Top Control Module indicating if the required trunk area is available for stowing the top.
The Folding Top Control Module supplies a switched filtered battery voltage to one terminal. The other terminal is a current source providing the signal to the Folding Top Control Module.
When the luggage barrier is deployed and properly seated in the retainer, the magnet is close enough to change the sensor's output current into the 2 to 7ma range and the sensor is considered active. When the luggage shade stem is removed from the retaining slot, the magnet is moved away from the sensor and this changes the sensor's output current into the 12 to 17ma range and the sensor is considered inactive.
Header Latch Position Switch
The front header latch secures the folding top to the top of the windshield area when the top is closed. The switch provides an input signal to the Folding Top control Module indicating whether or not the front header latch is engaged.
The Folding Control Module provides the Header Latch Switch with a referenced ground signal and monitors the input signal from the Header Latch Switch. The signal input is recognized as latched when the contact in the Header Latch Switch completes the circuit path to the referenced ground signal. When the switch is unlatched, the circuit is open and the signal circuit is pulled up to Battery by the Folding Top Control Module.
Pump Motor Control
The hydraulic pump's electric motor generates the pressure and determines the direction of the system's hydraulic fluid used to provide the actuating force for the folding top. The Folding Top Control Module controls the motor and its direction by two outputs which provide the motor supply voltage. The direction of the motor is determined by which output provides the ground and which one provides Battery power.
Power Top Operation
Once folding top movement has begun, the switch must be held active for the full range of motion. If the switch returns to the ‘off' position while the Power Convertible top is in motion all motion will cease.
Coordination Between Trunk
The Folding Top Control module monitors data it receives over low speed GMLAN regarding the status of the trunk. Folding top operation will not be allowed to initiate if the trunk is open. Additionally, the trunk will not be allowed to open if the folding top is not latched to the windshield header or it is not in the stowed position.
Rear Window Defog Interaction
The function of the rear window defog shall be disabled whenever the top is not in the fully closed and latched position. The status of the rear defog will not be a factor in initiating folding top movement.
Open/Down
When the Folding Top Control Module sees the Open Signal from the Folding Top Control Switch go active, it will start to open the folding top provided all of the following are true.
Once folding top movement has begun, the switch must be held active for the full range of motion. If the switch returns to the ‘off' position while the power convertible top is in motion all motion will cease.
If the Control Switch is held active while the pump motor is turned on, the motor will run for approximately 35 seconds unless the Stowed Switch becomes active. After this time the motor will be turned off until the Control Switch returns to the Off position and is re-activated.
When the folding top is moving down (open) and the Stowed Sensor becomes active, the pump will continue to run for up to 4 seconds or until a motor stall is detected. This is true whether the switch is held or released. This is to insure the proper pressure remains in the system to keep the top properly secured in the stowed position
Although a vehicle speed of less than 3 kph is required to initiate motion, top movement will continue until vehicle speed reaches 16 kph. Top movement will cease for vehicle speeds above this.
Close/Up
When the Folding Top Control Module sees the Close Signal from the Folding Top Control Switch go active, it will start to close the folding top provided all of the following are true.
System Protection Functions
Normal operation of the Folding Top system may be altered by one of the following events.
Obstacle Detection (aka: Blockage Detection)
The obstacle detection implemented for the Camaro power convertible top is only to protect the folding top mechanism and/or to detect a catastrophic mechanical failure.
If an excessive current draw is detected while the folding top motor is operating for a defined period of time the Folding Top Controller will turn off the folding top motor to prevent overheating or damage to the mechanical structure of the top.
Folding Top System Thermal Protection
The Folding Top Control Module has a thermal protection algorithm to protect the folding top pump motor from damage due to overheating conditions resulting from excessive motor actuation. After the thermal protection has been triggered any new power convertible top command in the open direction will be ignored until the motor is allowed to cool. A close request during an over temperature condition will be allowed.
DIC Messages and Chimes
