This is the last of three case studies presenting a complete A/C system using OEM (Original Equipment Manufacturers) information. The case study is not written in textbook fashion. This is because the purpose of each case study is for the reader to appreciate the breadth and depth of information available and what information is required to enable the technician to successfully work on such systems.The author has attempted to try to present the information in a logical order. Explanations have been written to assist in the understanding of system operation. If the reader fails to understand a particular aspect of the case study then refer to a section which covers that topic. Information from Vauxhall is usually sourced electronically on
Figure 3.153
CD-ROMs.The Vauxhall information system is called TIS 2000 which includes technical infor-
mation, diagnostic routines, bulletins, wiring diagrams, key programming and the facility to
link with diagnostic equipment like TECH 2.
Described using OEM information:
Vauxhall
Electronic Climate Control (ECC)
Automatic temperature control
Single evaporator – dual zone
Expansion valve control
Available for the Vectra-C is a newly developed Electronic Climate Control (ECC) system.
The Vectra-C features a new user interface concept for its ECC system.The system is oper-
ated via a control panel through a menu structure that is displayed on the centrally placed
Graphic Info Display (GID) or Colour Info Display (CID).
Furthermore the system includes features such as:
● air quality sensor;
● dual sun sensor;
● rest-climatisation (reduces hot spots and measures UV intensity);
● remote controlled parking heater (future).
Heating and ventilation
The control panel for the heating and ventilation system incorporates a control module. This
control module controls:
● the position of the flaps;
– air temperature/mix flap (stepper motor);
– air distribution flap (stepper motor);
● the blower speed (four different speeds: supply via shunt resistors or directly by a relay);
● rear window heating.
Without air-conditioning or ECC, the Vectra-C does not feature a recirculation valve.
Figure 3.154
Air filtration
The pollen filter is located under the water deflector and is available as a filter with activated
carbon layer.
Figure 3.155
Control panel heating and ventilation
There is no feedback on the actual position of the mix and distribution flap. Using so-called
overstepping ensures the actual position. If a flap is moved to the fully opened or closed pos-
ition, under certain conditions, the nominal number of steps is increased by 5%, to make sure
the flap reaches this position.Also, when switching OFF the ignition, the flaps are set in the
parking position (fully opened or closed) with 5% overstepping.This means that synchronisa-
tion of the flaps is no longer needed (or even possible).
Controls for electronic climate control
The communication between the A/C control panel and display takes place via the mid-speed
CAN bus.The controls for the ECC feature four switches and three rotary knobs for selection
of the ECC functions.The defrosting, rear screen heating, automatic and recirculating air func-
tions can be activated via the four switches. Each of these functions has a status LED inte-
grated in the switch, which indicates which function is currently active.The temperature is set
separately for the driver and passenger via the left and right rotary knobs. The central knob
serves to manually adjust blower speed and select the ECC functions from the menu. It is dis-
played on the GID (Graphics Interface Display) or CID (Colour Interface Display).The knob
can be turned to the right or left to scroll down the menu, and the menu options are selected
by pressing the centre knob.
Multiplex communication
The ECC is the central control unit for controlling the interior vehicle temperature. For this pur-
pose, it is provided with temperature, air quality and sun sensors in order to measure the current
environmental conditions as well as actuators to actuate the air flaps, the fan and the AC com-
pressor (via the CAN bus system). ECC also actuates the rear screen heating and the auxiliary
heating. In order to prevent overloading the engine (in particular during idling), the ECC
exchanges the ECC operating conditions and request signals with the engine control unit via the
CAN bus. These messages are transmitted to and from the HSCAN and MSCAN via the CIM
(Column Interface Module) (HSCAN to LSCAN) and the GID/CID interface (LSCAN to
MSCAN).
Bus interface to mid-speed CAN (MSCAN)
The ECC has two connections to the mid-speed CAN bus. They serve to loop the mid-speed
CAN bus through the control unit.The control unit electronics are then internally connected
to the looped-through mid-speed CAN bus. If the ECC control unit is not connected, the mid-
speed CAN bus is interrupted.
Display actuation function
Among other tasks, the GID/CID is responsible for the display of all ECC menus. Further-
more, information that needs to be transmitted from the ECC to other control units in the
CAN network is transmitted to the low speed CAN bus by the GID/CID (interface function).
If this information is destined for control units connected to the high speed CAN bus, the CIM
effects the transmission from the low speed CAN bus to the high speed CAN bus.
Dimmed illumination function
The BCM (Body Control Module) transmits the dimming value for the interior illumination
via the low speed CAN bus.After receiving this message, the ECC adjusts the intensity of illu-
mination of the control panel according to the dimming value.
Figure 3.156
Figure 3.157
Figure 3.158
From the main menu it is possible to select:
● air distribution;
● switching the air-conditioning ON/OFF (similar to ECC on the previous systems);
● switching the auto recirculation (by means of the air quality sensor) ON/OFF.
Figure 3.159
When selecting ‘Air Distribution’ and confirming by pressing the centre rotary control, the Air
Distribution menu is displayed.
By selecting the three possible air outlets with the centre rotary control, all possible com-
binations can be made manually.To return to ‘Auto Air Distribution’ select ‘Auto’ from this menu
or press the Auto button on the ECC control panel.
System activation and deactivation
To switch the compressor ON/OFF, select or deselect the option ‘Air-conditioning’. As with
the Eco button, the heating and ventilation remains in Auto mode but without the help of air-
conditioning.
ECC features an air quality sensor that enables auto recirculation.This feature can be acti-
vated by pressing the recirculation button twice.On Vectra-C auto recirculation is enabled as
default.Auto recirculation can be disabled with the option ‘Air Quality Sensor’ from the ECC
main menu.Recirculation can also be switched ON manually, by using the switch on the ECC
control panel. The manual recirculation has priority over the Auto Recirculation function.
During manual recirculation, the status of the Auto Recirculation remains active.When the
manual recirculation is switched OFF, the Auto Recirculation remains enabled.Again, this is
indicated in the ECC main menu.
ECC components (Figs 3.160 and 3.161)
The ECC system consists of the following components:
● ECC control module/control panel.
● Display (GID or CID).
● Evaporator sensor.
● Output air temperature sensor, outlet footwell left/right and outlet passenger compartment
left/right.
● Dual sun sensor with integrated in-car temperature sensor.
● Air quality sensor.
● Air mix flap stepper motor, left and right.
● Passenger compartment outlet flap stepper motor.
● Footwell outlet flap stepper motor.
Figure 3.160
Figure 3.161
● Defrost outlet flap stepper motor.
● Recirculation flap DC motor.
● Blower with blower control unit.
● Electrical coolant recirculation pump (only when equipped with a parking heater).
● Compressor clutch control coil.
● Parking heater (future option).
● Parking heater remote control (future option).
Pulsation damper
Pulsation dampers are installed to prevent noise, which is generally caused by the pressure
pulses of the compressor.
Figure 3.162
Pressure sensor
To ensure that the air-conditioning system operates safely at all times, the refrigerant circuit is
monitored on the high pressure side.The pressure sensor responds and switches off the compres-
sor if the operating pressure reaches approximately 30 bar.The pressure sensor switches the com-
pressor on again when the pressure drops below the normal operating state of approximately 26
bar.The pressure sensor also switches on the auxiliary fan, depending on outside temperature and
coolant temperature.
Evaporator surface temperature sensor
The ECC system is equipped with a device to prevent icing of the evaporator surface. Instead
of operating as a switch and interrupting the A/C command from the control panel, the Vectra-
C uses a temperature sensor as an input of the ECC control unit.When the evaporator tem-
perature drops below the threshold of 1.5°C, the ECM (Engine Control Module) will
receive a signal from the ECC control module via the CAN bus to deactivate the compressor
clutch.At 1.2°C, the compressor is activated again.
Outlet air temperature sensors
Four NTC resistors (10 k at 25°C) are used to measure the temperature of the air coming out
of the heater housing: two for the floor outlets (left/right) and two for the upper outlets
(left/right).The ECC control unit determines the desired position of the air mix flaps through
the input from these sensors.
B77 dual sun sensor with in-car temperature sensor
The function of the dual sun sensor is to determine the sunlight intensity.The sensor is equipped
with two identical photodiodes for direction recognition.The signals are supplied to the ECC con-
trol module via two separate terminals.The sun sensor is located on the centre of the instrument
panel on the defroster nozzle.The sensor does not only contain the photodiodes but also the in-
car temperature sensor (NTC, 5 k at 25°C) (Fig. 3.163).
Figure 3.163
Figure 3.164
Figure 3.165
Air quality sensor
The air quality sensor (see also Fig. 3.52) is located under the water deflector, left of the pollen
filter (Fig. 3.164).This forms an input signal for the automatic recirculation.Like the pollen fil-
ter and the activated charcoal filter, it helps improve the on-board climate. By chemical reac-
tions on its surface, the air quality sensor is able to detect localised ground level contamination,
such as harmful diesel or petrol fumes.At traffic lights, e.g. when directly behind a truck or if
driving through a tunnel, exhaust gas peaks occur which can be up to 1000 times higher than
the exhaust gas concentration in the general environment.
If the vehicle is in such an exhaust gas cloud, the air intake process will always be stopped
and the system will switch to recirculation mode. To prevent the air quality in the passenger
compartment from becoming worse than the air outside, which could happen in some cases if
recirculation mode were on permanently and the air in the passenger compartment was not
being exchanged at all, the system works dynamically. In exceptional cases such as these, this
mode of operation ensures that an adequate supply of fresh air is fed into the system. For tech-
nical data see section 3.2.
Stepper motors
The ECC system operates five stepper motors, two for the temperature blend function (one
motor for the driver temperature zone and one for passenger temperature zone), and one each
for the following, defrost flap (windscreen), face flap ventilation and floor flap. For motor spec-
ification see Fig. 3.165.
Figure 3.166
Blower motor with voltage regulator
The blower voltage regulator is connected to the ECC control module via a command line and
a diagnostic line. Using a PWM (see section 3.2) signal the ECC control unit reports the
desired blower speed to the blower voltage regulator.The blower control module controls the
blower motor through a 2KHz PWM signal. Figure 3.166 provides a wiring diagram.
ECC special features
The following special features apply to the ECC system.
Rest-climatisation
It is possible to make use of the residual heat/cold of the HVAC system after the ignition is
switched OFF. If the Auto button on the control panel is pressed, after ignition OFF, the ECC
is activated and the display indicates the ambient, driver and passenger temperature and the
rest-climatisation symbol (‘Residual Air-conditioning On’).
It is now possible to adjust the desired temperature.The blower speed is fixed and cannot be
adjusted manually in the rest-climatisation mode.
With an increasing deviation between the desired and actual outlet air temperature, the blower
voltage is gradually reduced to 0V.Below a battery voltage of 10.7V, the rest-climatisation mode
is disabled.
Rest-climatisation and anti-theft warning system
It is possible to activate the rest-climatisation, leave and lock the vehicle.When equipped with
an Anti-Theft Warning System (ATWS), the circulation of air may cause problems when arm-
ing the interior monitoring (ultrasonic module).
To prevent this, the interior monitoring is deactivated/disabled with a request/message from the
ECC control module to the BCM (Body Control Module). Once the rest-climatisation stops, a
message from the ECC control module to the BCM ensures that the interior monitoring is armed.
Blower delay
Similar to previous ECC systems, in the Auto mode the blower speed is gradually increased after
an engine start.This is done to cool down the evaporator first, before a large amount of air flows
through it.The delay depends on the ambient temperature and can extend up to 8 seconds.This
delay can be overruled manually by increasing the blower speed with the centre rotary control.
Figure 3.167
Defroster delay
If the defrost button is pressed after an engine start, the defrost flap remains closed up to a max-
imum of 30 seconds.During this delay, the air is directed to the footwell to get rid of the mois-
ture in the heating and ventilation housing.This way, fogging up of the windows is prevented in
defrost mode. Like the blower delay, the defroster delay depends on the ambient temperature.
Logistic mode
In the Logistic mode, the ECC cannot be disabled completely, because the defrost function for the
windscreen is required by law.All after-run functions (ignition OFF) are disabled because their
only function is comfort and not safety. Furthermore the ECC control module is not allowed to
‘wake up’ any of the CAN buses, or activate the parking heater (future option) or rest-climatisa-
tion.The flaps remain in the last position used.No overstepping is performed after ignition OFF.
Electrical information
Fuse box information illustrated using Vauxhall’s TIS (Technical Information System which is
CD-ROM based).
Fuse box/relay plate
figure 3.168
tabel
Figure 3.169
tabel
ECC block diagram
The block diagram in Figure 3.170 illustrates the input and output relationships between the
A/C system module,A/C components and other modules that share information via a multiplexed
network. The use of the component information chart is used to match the codes with the
Figure 3.170
Figure 3.171
components (DIN Standard Codes).Once an understanding of the block diagram is achieved
make use of the wiring schematic.
Component information
ECC system wiring schematic
The wiring schematic and pin layout in Figure 3.171 is used to aid the understanding of the
operation of the system.
Explanation of wiring schematics
The ECC is the central control unit for controlling the interior vehicle temperature.This mod-
ule controls all the heating and ventilation controls and acts as a user interface by including
selection knobs and switches. The module controls HVAC door motor positions and blower
speed based on information provided from sensor inputs on temperature, sun intensity and air
quality.The ECC module also controls the independent heater (see Chapter 1).The ECC has
two connections to the mid-speed CAN bus. They serve to loop the mid-speed CAN bus
through the control unit. The control unit electronics is then internally connected to the
looped-through mid-speed CAN bus. If the ECC control unit is not connected, the mid-speed
CAN bus is interrupted.
In order to prevent overloading the engine (in particular during idling), the ECC exchanges
the ECC operating conditions and requests signals with the engine control unit via the CAN
bus.These messages are transmitted to and from the HSCAN and MSCAN via CIM interface
(HSCAN to LSCAN) and the DIS interface (LSCAN to MSCAN).The activation of the A/C
compressor is not carried out by the ECC module, it is activated upon a request signal gener-
ated by the ECC module which is sent to the engine control module (A84) via the CAN bus
system.
P6 (information display,Graphics Information Display (GID), Colour Information Display
(CID)) shares information on a medium speed CAN data bus. Information will consist of sig-
nals for display purposes (temperature and blower speed etc.). The communication between
the control panel and display takes place via the mid-speed CAN bus.Among other tasks, the
GID/CID is responsible for the display of all ECC menus. Furthermore, information that
needs to be transmitted from the ECC to other control units in the CAN network is transmit-
ted to the low speed CAN bus by the GID/CID (interface function).
Important
If this information is destined for control units connected to the high-speed CAN bus, the CIM
effects the transmission from the low-speed CAN bus to the high-speed CAN bus. For exam-
ple, if the evaporator temperature sensor (B5-A14) output voltage equated to a temperature
approaching ice formation on the evaporator housing then this signal would be sent via the
MSCAN to P6. The signal would then be sent from P6 (display) to BCM (A15 body control
unit) via the LSCAN.The BCM is connected to the CIM (A105 column integrated module) via
the LSCAN. The CIM has the facility to interface with LSCAN and HSCAN systems so the
signal will travel via the HSCAN to the ECM (A84 engine control module). Upon receiving
the signal the ECM will de-energise the compressor coil.
figureeee.....................
Engine Control Module (ECM) – compressor control (Fig. 3.172)
Compressor clutch L7 is controlled by the ECM. The ECM provides a ground signal to K8
compressor relay. This allows current to flow from relay K8 to compressor coil L7 and to
ground. Current will also flow to pin 4 of the ECC module.This acts as confirmation that the
ECM has activated or deactivated the A/C compressor clutch.
The compressor has a control pressure sensor to protect the system in case of overpressure
or loss of pressure.This signal is sent to the ECM enabling the clutch to be de-energised in the
event of a system failure.
Diagnostic information
These are the procedures to be followed to obtain the required test results.
Delivery temperature
Preparatory conditions:
1. All windows and doors closed.
2. All ventilation outlets fully open.
Figure 3.172
3. Engine idling.
4. Select ‘LO’ on the A/C control module.
5. A/C/heater blower motor set to maximum speed.
6. Recirculation mode selected on the A/C control module.
7. A/C control module set to vent.
Checking:
1. Run engine at 1500–2000 rpm.
2. Position temperature probe 100mm into fascia ventilation centre outlet.
3. Measure temperature after 5 minutes.
figure...............
Refrigerant pressures
Preparatory conditions:
1. All windows and doors closed.
2. All ventilation outlets fully open.
3. Engine idling.
4. Select ‘LO’ on the A/C control module.
5. A/C/heater blower motor set to maximum speed.
6. Recirculation mode selected on the A/C control module.
7. A/C control module set to vent.
8. Run air-conditioning for 5 minutes prior to testing.
Checking:
1. Run engine at 1500–2000 rpm.
figure...............
Self-diagnosis
The A/C control module fault memory can only be checked using diagnostic equipment con-
nected to the Data Link Connector (DLC).
Trouble codes
Suitable diagnostic equipment is required to obtain and erase data from A/C control module
memory. See Table 3.11 for a list of codes.
Data logger using Tech 2 – ECC system
Table 3.12 provides a data list that was obtained from a vehicle at the Vauxhall Training Centre
by the author. The data list was accessed using the scan tool Tech 2. Note this data is not
live but simulated by the module (interfaced) to enable the technician to understand what
operating conditions and input/output information is being received and sent by the ECC
module.
figure,,,,,,Table 3.11
Table 3.12
Actuator tests
The following actuator tests are available using a Tech 2 tester:
● Recirculation motor test results: recirculation – moving – fresh.
● LED test on display results: dim/bright.
Technical data
figure............
Service note
The dashboard does not need to be removed to gain access to the evaporator.
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