Timed Climate Control

Where fitted, timed climate control provides a comfortable temperature in the passenger compartment of a vehicle parked with the engine off. When timed climate control operates, the passenger compartment is either heated by the Fuel Fired Booster Heater (FFBH) and climate control blower (parked heating) or cooled by the climate control blower (parked ventilation), depending on the ambient air temperature. Parked heating occurs if the ambient air temperature is less than 16°C (61°F). Parked ventilation occurs if the ambient air temperature is 16°C (61°F) or more. To prevent excessive drain on the battery, both parked heating and parked ventilation are automatically de-activated after 30 minutes.

In very cold conditions timed climate control also warms the engine to aid starting. Engine warming occurs if the ambient air temperature is -25°C (-13°F) or below.

When timed climate control is operating, the Light Emitting Diode (LED) in the AUTO or A/C switch on the Integrated Control Panel (ICP) will flash. If the AUTO switch LED flashes the engine or passenger compartment are being heated. If the A/C switch LED flashes the passenger compartment is being ventilated.

Timed climate control is controlled using either the touch screen or the FFBH remote control.

In order to minimize the potential for odor ingress from the FFBH, the ATCM (Automatic Temperature Control Module) will automatically close the recirculation door in the climate control assembly for the first few minutes of FFBH operation when activated by the timed climate control feature.

Touch Screen 

The touch screen is used for direct selection of timed climate control or to program one or two 'on/off' cycle start-times per day, and one 'on/off' cycle start-time further in the future. The programmed start times are stored in the Body Control Module/Gateway Module (BCM/GWM). The direct selection and programmed time modes of operation are selected when the engine is stopped and the smart key is in the vehicle. The key can then be removed and the vehicle locked. Any timed event will automatically run without the key inside the vehicle.

At a programmed start time or a direct selection on the touch screen, the BCM/GWM sends a start signal to the Automatic Temperature Control Module (ATCM) via the High Speed (HS) Controller Area Network (CAN) comfort systems bus. The ATCM module then initiates the appropriate mode of timed climate control operation.

To set a timed climate program:

1. Press the HOME MENU switch.
2. Touch the Timed climate  soft key. This soft key may be set on a personal shortcut or accessed via the Extra Features  soft key. Select 7 day timer, or single event, then select the timer soft key. If the 7 day timer is selected, then select the day for which you want to set a program. Alternatively, select All week  to select the same start time for every day.
3. Touch the Timer 1 or Timer 2 soft key. The timers can be toggled between on and off using the power soft key.
4. Touch the up or down arrows to set the start time. Hours and minutes are adjusted separately.
5. Touch OK  . The screen will display the activation time. If required, set the time for the other timer using the same process.
6. Once set, the timer events can be turned on or off as required in the Timed climate screen by selecting the 7 day timer or the single event soft key.

Any programmed timed climate control cycle may be cancelled by touching the relevant power soft key on the timer set up menu or the Power  soft key on the Timed climate  information home menu.

Remote Control 

When timed climate control is selected on or off with the Fuel Fired Booster Heater (FFBH) remote control. The request is received by the FFBH receiver via the right TV antenna and the TV antenna amplifier. The FFBH receiver relays the request as a hardwired signal to the Fuel Fired Booster Heater Control Module (FFBHCM). On receipt of the request, the FFBHCM sends the request to the Automatic Temperature Control Module (ATCM) on the Local Interconnect Network (LIN) bus. The ATCM then initiates the appropriate mode of timed climate control operation.

A 'handshake' signal is sent back from the FFBH receiver to the FFBH remote control to confirm a valid on or off request and activate the remote control Light Emitting Diode (LED) accordingly.

Timed Climate Control Operation 

When the ATCM (Automatic Temperature Control Module) receives a timed climate control start request, its response depends on the ambient air temperature:

• If the ambient temperature is 15°C (59°F) or more, the ATCM initiates parked ventilation and:
  • Operates the blower, depending on the ambient temperature, between 35% and 50% of the maximum speed.
  • Operates the distribution doors in the heater assembly to direct the air to the face vents.
• If the ambient temperature is less than 16°C (61°F) and more than -25°C (-13°F), the ATCM initiates parked heating and:
  • Energizes the FFBH coolant changeover valve.
  • Sends a Local Interconnect Network (LIN) bus message to activate the Fuel Fired Booster Heater (FFBH).
  • Operates the blower, depending on the ambient temperature, between 35% and 50% of the maximum speed.
  • Operates the distribution doors in the heater assembly to direct the air to the footwell vents for approximately 30 seconds. Then to either only the windshield, or to both the footwell vents and the windshield, depending on the ambient air temperature.
• If the ambient temperature is -25°C (-13°F) or below. The ATCM sends a LIN bus message to activate the FFBH, but leaves the FFBH coolant changeover valve de-energized and does not operate the blower or distribution doors. Heated coolant is circulated around the engine and heater core(s) to heat the engine and improve engine starting. Once the FFBH coolant temperature is above a suitable threshold the blower is switched on and passenger compartment heating commenced.

The FFBH will only activate in timed climate control if the following threshold conditions are met:

• Pre-burn primary battery voltage check: ≥11.5V (at the FFBH terminals).
• Pre-burn Engine Coolant Temperature (ECT) check: ≤15°C (internal FFBH measurement).
• Pre-burn fuel level check: ≥7.5 liters (value stored in the FFBH at ignition off).

The fuel level value stored within the FFBH is only updated when the engine is running. When starting the FFBH in timed climate control with the engine off, the fuel level value used in the FFBH calculations will be that stored at the ignition off event. It is therefore possible for the FFBH to fail to operate in timed climate control if the engine was stopped with a low fuel level. If the fuel tank is subsequently refueled, the FFBH stored fuel level will still read low if the engine has not been started since refueling.

After 30 minutes, or if timed climate control is selected off with the touch screen or remote control, the ATCM discontinues timed climate control operation:

• If parked ventilation is active, the ATCM:
  • Switches off the blower.
  • Returns the distribution doors to the previous settings.
• If parked heating is active, the ATCM:
  • Sends a LIN bus message to de-activate the FFBH.
  • Switches off the blower.
  • Returns the distribution doors to the previous settings.
  • After 3 minutes, de-energizes the FFBH coolant changeover valve.

Transition from Timed Climate Control to Engine Running 

Parked ventilation is automatically de-activated when the ignition is switched on.

Parked heating:

• Is de-activated when the engine starts if the Engine Coolant Temperature (ECT) is equal to or more than the heater coolant temperature.
• If the ECT is less than the heater coolant temperature, parked heating remains active until the ECT reaches the heater coolant temperature. The FFBH coolant changeover valve also remains closed until the ECT reaches the heater coolant temperature.