Automatic A/c-Heater Systems - 9-5: Other Saab 9-5 I рестайлинг

AUTOMATIC CLIMATE CONTROL (ACC) CONTROL UNIT

Automatic Climate Control (ACC) control unit consists of a control panel with an active function display, control buttons, and an integrated control module. (Scheme 13) Under normal conditions the ACC control module maintains selected temperatures for one driver and two passenger zones (front and rear). Control of temperature in each zone is based on pre-selected temperatures and information from 5 sensors. ACC control module calculates actual zone temperature and compares it with outside and pre-selected temperatures. When a difference in temperature is detected, ACC control module changes position of mixed-air flap for affected zone.

When engine is started, ACC control module begins to regulate cabin temperature. Automatic system control will be cancelled if a manual mode function has been selected or operator programming has been performed. When a manual mode function has been selected, like changing blower motor speed for example, system will lock in on selected mode. Remaining modes will continue to be controlled automatically.

When ignition is turned off, ACC control panel display goes out, no buttons operate, all stepping motors are turned off, and air recirculation off is selected after 10 seconds. Diagnostics communication will remain active if it was active when ignition was turned off. ACC control module is active for 10 minutes after ignition is turned off. If ignition is turned on within 10 minutes, any manual selections will be retained. After 10 minutes, ACC control module will start in AUTO mode or operator programmed mode. If battery voltage is less than 9.5 volts and starter is not operating, ACC display will show OFF until battery voltage is more than 10.0 volts.

Scheme 13

A/C COMPRESSOR CLUTCH ACTIVATION

A/C compressor operation is activated automatically when ACC control panel is on (OFF button has not be selected), ECON is not selected, engine is operating, and ambient air temperature is more than 41°F (5°C). A/C request goes to Dashboard Integrated Central Electronics (DICE) control module via the communication bus. DICE control module receives information from sensors and the TRIONIC engine control module and confirms A/C operating parameters are met.

The DICE control module will send an A/C request to TRIONIC module if engine coolant temperature is less than 257°F (125°C), A/C system pressure is 29.0-391.6 psi (2.0-27.5 kg/cm 2 ), and evaporator temperature is more than 37°F (3°C). If evaporator temperature is less than 32°F (0°C) then DICE control module will only send an A/C request if ambient temperature is more than 77°F (25°C), engine has been operating for less than 30 minutes, and vehicle speed is less than 3 MPH. When conditions for A/C operation are met, the TRIONIC module will ground A/C relay and energize A/C compressor clutch.

COMPRESSOR SAFETY VALVE

Compressor safety valve is a mechanical valve located on top of compressor. Safety valve opens, releasing refrigerant to the atmosphere, when refrigerant pressure increases to 565.7 psi (39.8 kg/cm 2 ). Safety valve closes when refrigerant pressure decreases to 493.1 psi (34.7 kg/cm 2 ) or less.

AUTO Mode

When AUTO button is selected, all climate control functions are automatically controlled. (Scheme 13) Occupant selected temperature and AUTO are displayed. When AUTO button is selected again, the full display is shown and current settings are stored in ACC control module memory as the default value. ECON, electrically heated rear window, and temperature up or down can be selected without deselecting AUTO. ACC system always starts in AUTO mode, unless it has been reprogrammed.

ECON Mode

When ECON button is selected, A/C and air recirculation are turned off, and ECON will be displayed. (Scheme 13) AUTO will continue to be displayed. When manual operation has been selected by selecting the OFF button, ECON functions can be programed.

Air Recirculation Mode

The air recirculation button turns manual air recirculation on and off. (Scheme 13) When air recirculation button is selected, air recirculation is turned on and button symbols are displayed. AUTO will be displayed even though air recirculation is manually controlled. To return to automatic control, AUTO button must be selected.

Defrost Mode

When front defrost button is selected, blower motor is activated, heated rear window and door mirror heating elements are activated, A/C is turned on, and ECON is turned off. (Scheme 13) Air is directed through front defrost outlets to windshield and front side windows. Air recirculation is turned off. Normal temperature control continues. All active function symbols and selected temperatures will be displayed, except AUTO. When air distribution is in defrost mode, diagnostic scan tool will indicate 100 percent.

Defrost/Floor Mode

When front defrost and floor buttons are selected, air is directed through front defrost and floor outlets. (Scheme 13) All active function symbols and selected temperatures will be displayed, except AUTO. When air distribution is in defrost/floor mode, diagnostic scan tool will indicate 70 percent.

Floor Mode

When floor button is selected, a majority of air is directed through floor outlets with a small amount directed through front defrost outlets. (Scheme 13) There are 4 floor outlets, 2 direct air to floor under instrument panel and 2 direct air to back seat floor and to rear door windows. All active function symbols and selected temperatures will be displayed, except AUTO. When air distribution is in floor mode, diagnostic scan tool will indicate 50 percent.

Floor/Panel Mode

When floor/panel button is selected, air is directed through floor and panel outlets. (Scheme 13) All active function symbols and selected temperatures will be displayed, except AUTO. When air distribution is in floor/panel mode, diagnostic scan tool will indicate 25 percent.

Panel Mode

When panel button is selected, air is directed through 4 instrument panel outlets and 2 rear center console outlets. (Scheme 13) All active function symbols and selected temperatures will be displayed, except AUTO. When air distribution is in panel mode, diagnostic scan tool will indicate zero percent.

MIXED-AIR TEMPERATURE SENSORS

There are 2 mixed-air temperature sensors. One sensor is inserted into each floor outlet. (Scheme 14) ACC control module uses sensor values, to control positions of right and left mixed-air flaps, to maintain selected mixed-air temperature at floor outlets.

The mixed-air temperature sensors are a rod thermistor, which has a negative temperature coefficient. Voltage across sensor decreases as temperature increases. ACC control module supplies sensor ground from terminal No. 37 (right side) and terminal No. 38 (left side), and 5 volts through a 5600 ohm integrated resistor to each sensor from terminal No. 18 (right side) and terminal No. 19 (left side).

Scheme 14

AIR RECIRCULATION MOTOR

Two linked air recirculation flaps are operated by a direct current motor. (Scheme 14)and (Scheme 15). Depending on position of recirculation flaps, the blower motor can be supplied with either outside air or cabin air. There are no intermediate positions. Battery voltage is supplied from ACC control module terminals No. 2 and 21 for only 10 seconds during flap position change. Polarity of battery voltage is reversed to change direction of motor rotation and flap position. When ignition is turned off, ACC system will default to outside air position after 10 seconds.

MIXED-AIR FLAP STEPPING MOTORS

Mixed-air flaps and air distribution flap are operated by electrical stepping motors. (Scheme 14)and (Scheme 15). Each stepping motor has 2 windings that are energized with short pulses in a specific order. When air flap is in desired position, both windings are energized continuously to lock stepping motor in position.

The ACC control module controls air flap position by sending a specific number of pulses to energized stepping motor. The ACC system stepping motors do not require a flap position feedback signal to ACC control module. The ACC control module calibrates each air flap position by setting air flap to both end positions.

If a stepping motor has been replaced, air flap position has been changed independent of ACC control module control, or battery has been disconnected, ACC control module must be recalibrated. During calibration, ACC control module moves each flap to its end position. See ACC CONTROL MODULE CALIBRATION under PROGRAMMING.

SOLAR SENSOR

The solar sensor is located on top of dashboard. (Scheme 14) ACC control module calculates intensity, height, and angle of sun in relation to car using information from solar sensor. ACC control module uses sensor value to calculate head height temperature for driver and front passenger. Every 440 milliseconds the ACC control module looks for a solar sensor signal.

Solar sensor consists of 5 infrared-sensitive elements that face left, right, forward, back and up. ACC control module supplies pulsed battery voltage to sensor from terminal No. 16 and ground from terminal No. 36. Each solar sensor element signal is sent consecutively to ACC control module terminal No. 17. A continuous 5-volt, 0-volt, 5-volt identification pulse precedes each group of signals so ACC control module can separate each signal. Solar sensor pulse signals are synchronized by short ground pulses from ACC control module terminal No. 16.

HEATER CORE

The heater core is located in A/C-heater assembly. (Scheme 15) Flow of engine coolant to heater core is controlled by a vacuum operated heater core shutoff valve. To increase temperature control, ACC control module will increase or decrease flow of engine coolant through heater core. Vehicle may be equipped with a heater core circulation pump to increase coolant flow through heater core during low engine speed.

COOLANT CIRCULATION PUMP

Some models are equipped with an engine coolant circulation pump. (Scheme 14)and (Scheme 15). Circulation pump is used to increase coolant flow to heater core during low engine speeds. Circulation pump can be used to circulate engine coolant when parking heater function is activated.

During engine operation, circulation pump will be activated by ACC control module when engine speed is less than 1600 RPM and outside temperature is less than 32°F (0°C). Circulation pump will be deactivated when engine speed is more than 2000 RPM, or outside temperature is more than 41°F (5°C).

HEATER CORE SHUTOFF VALVE

To increase cooling efficiency, the climate system is equipped with a vacuum controlled heater core shutoff valve to control coolant flow through heater core. ACC control module closes shutoff valve by energizing a solenoid vacuum valve. Heater core shutoff valve will be closed when cabin temperature must be reduced more than 10°F (6°C) to attain selected temperature for all cabin zones. Heater core shutoff valve is located in front of firewall, under charge air by-pass valve solenoid valve.

Scheme 15

COLD START FUNCTION

When ambient air temperature is cold during engine start, ACC control module attempts to defrost windshield and then warm cabin air as quickly as possible. Cold start function will be activated if calculated air temperature at head height of driver is less than selected temperature displayed on ACC panel display and ambient temperature is less than 43°F (6°C). Air distribution and blower motor speed are determined based on engine coolant and ambient air temperatures.

When ambient air temperature and engine coolant are cold, blower motor speed selected will be slow in an attempt to maintain highest air temperature possible after heater core. Blower motor speed will be increased as engine coolant temperature increases. Air distribution at engine start will be in defrost mode until engine coolant temperature is 149-167°F (65-75°C). When engine coolant has increased to specified temperature defrost/floor mode will be selected.

Default ambient air temperature, used by ACC control module to select defrost mode during cold start function, can be adjusted using a scan tool. Default coolant temperature, used by ACC control module to select defrost/floor mode during cold start function, can be adjusted using a scan tool.

CONDENSER COOLING FANS

Vehicle is equipped with two dual-speed condenser cooling fans, located behind radiator. Fan operation is controlled by DICE control module based on A/C system pressure and 3 other input signals. Communications bus sends engine coolant temperature signal from TRIONIC engine control module, vehicle speed from Main Instrument Unit (MIU), and ambient air temperature from Saab Information Display (SID).

When engine coolant temperature is 212°F (100°C) or more, DICE control module will energize low speed fan relay (located in engine compartment main fuse/relay box). Both fans will operate at low speed. When engine coolant temperature increases to 232°F (111°C), DICE control module energizes 2 more relays (high speed fan relays).

When ignition is turned off, and for 30 seconds thereafter, low speed cooling fans will continue to operate, or start if engine coolant temperature is more than 220°F (104°C). Cooling fans will stop when coolant temperature decreases to less than 220°F (104°C). After one minute from turning ignition off, low speed cooling fans will continue to operate, or start if engine coolant temperature is more than 228°F (109°C). Cooling fans will stop when coolant temperature decreases to less than 228°F (109°C). After 3.5 minutes cooling fan operation will stop regardless of coolant temperature.

During A/C compressor operation, fans will operate at low speed if ambient air temperature is more than 72°F (22°C), or vehicle speed is less than 24 MPH and A/C system pressure is less than 131 psi (9.2 kg/cm 2 ). During A/C compressor operation, fans will operate at high speed if A/C system pressure increases to more than 261 psi (18.4 kg/cm 2 ).

EVAPORATOR

The evaporator is located in A/C-heater assembly. (Scheme 15)and (Scheme 16). The evaporator cools and dehumidifies the air before it enters passenger compartment. Warm air passing from outside or inside cabin, through evaporator core and back to cabin, is cooled to 41-50°F (5-10°C) and dehumidified. The amount of cooled, dehumidified air returning to cabin is controlled by ACC control module based on pre-selected temperature compared to current temperature. Any moisture (humidity) in incoming air condenses on the surface of evaporator core and is drained off as water. An evaporator temperature sensor protects evaporator from freeze-up by monitoring evaporator temperature.

EVAPORATOR TEMPERATURE SENSOR

The evaporator temperature sensor is inserted into a hole in evaporator cooling fins. (Scheme 16) Evaporator temperature sensor protects evaporator from freeze-up by monitoring evaporator temperature. Evaporator temperature signal is sent to DICE control module which controls operation of A/C compressor clutch. DICE control module will de-energize compressor clutch when evaporator temperature is approximately 32°F (0°C). DICE control module will energize compressor clutch when evaporator temperature increases to approximately 37°F (3°C).

Scheme 16

FRESH AIR FILTERS

The air filter is located on intake side of evaporator. (Scheme 15) The air filter is electrostatically charged to assist in trapping particles of all sizes including pollen and plant spores. Vehicle may also be equipped with an optional carbon filter located between air filter and evaporator. Carbon filter is designed to reduce fumes. Carbon filter can be installed if not originally equipped.

PARKING HEATER

Parking heater is used to maintain occupant selected temperature when vehicle is parked in cold weather. Parking heater function is activated when AUTO button is pressed after engine has been turned off. When ignition is turned off, ACC will continue cabin temperature control. When engine coolant temperature at parking heater outlet is at least 104°F (40°C), parking heater will supply battery voltage to ACC control module terminal No. 3.

The mixed-air flaps are controlled automatically according to selected temperature, air distribution flap is set to defrost position for 25 minutes and then to defrost/floor position, air recirculation flap is set to fresh air position unless outside temperature is less than 14°F (-10°C), and blower motor is set to low speed. ACC control panel will display blower motor speed.

Manual selections can be made with all buttons, except blower motor speed, ECON, and heated rear window. (Scheme 13) If AUTO button is pressed, a full ACC system function display is shown. Parking heater function will stop after about 30 minutes, when coolant temperature is less than 104°F (40°C), when ignition is turned on, or OFF button is pressed. ACC control module will return to normal system control when battery voltage to terminal No. 3 is interrupted.

WARM START FUNCTION

When ambient air temperature is warm during engine start, ACC control module attempts to cool cabin air as quickly as possible. Warm start function will be activated if calculated air temperature at head height of driver is approximately 9°F (5°C) more than selected temperature displayed on ACC panel display. Warm start function activation will continue until calculated air temperature at head height of driver corresponds with selected temperature. Warm function sets air distribution to panel position and blower motor speed almost to maximum. If necessary, blower motor speed will be gradually increased to maximum speed until calculated air temperature is the same as selected temperature.

FILLING ENGINE COOLING SYSTEM

Fill engine cooling system with a 50 percent concentration of anti-freeze to MAX level. Install pressure cap and start engine. Operate engine with A/C turned off at varying speeds until radiator/condenser cooling fans comes on. Carefully remove pressure cap and add coolant to MAX level again. Reinstall pressure cap and operate engine at varying speeds until radiator/condenser cooling fans have come on 3 times. Turn engine off and ensure coolant is at MAX level.

ACC CONTROL MODULE PROGRAMMING

Note. Manufacturer has found that approximately half of all ACC control modules thought to be faulty were actually user programmed. Before replacing ACC control module ensure user programming has been cancelled and malfunction verified.

User Programming

The ACC control module can have manual selections programmed by user that activate when vehicle is started. Functions not programmed by user will activate automatically according to ACC system parameters. ACC control module processor is active for 10 minutes after ignition is turned off. If ignition is turned on within 10 minutes of being turned off, any manual selections made during the last trip will be retained. After 10 minutes the ACC control module will use user-programmed selections.

To access ACC control module user programming, turn ignition on and press function button corresponding to desired function. (Scheme 13) Press OFF and heated rear window buttons simultaneously to save selection. Selected function will flash on ACC display. When user programming is complete, turn ignition off for at least 10 minutes to save selections in ACC system memory.

To cancel user programming, press AUTO and blower motor speed down buttons simultaneously. ACC display will flash to confirm selections have been cancelled. ACC control module can be programmed using a scan tool to always start with any manual selections made during the last trip.

Extended User Programming

Note. Extended user programming allows user to change activation parameters of certain automatic functions. These selections are stored and used by ACC control module until programming is cancelled, activating default parameters.

1. Turn ignition on. To program or cancel an automatic function, press ECON, air recirculation control, or heated rear window control button. (Scheme 13) Hold button until selected function symbol is displayed, flashes 4 times, and a chime is sounded. During programming a message will be displayed on Saab Information Display (SID). When programming is done, AUTO will still be displayed on ACC control panel.
2. During ECON programming, SID will display ACC: LOW TEMP A/C CTRL. During ECON program cancelling, SID will display ACC: NORMAL A/C CTRL. The ACC control module automatic default selection of ECON function will occur when outside temperature is less than 50°F (10°C) and calculated solar intensity is less than a specific value. ECON function will disengage when outside temperature is more than 55°F (13°C) or calculated solar intensity is more than a specific value. ACC control module will not accept increased temperatures if vehicle speed is less than 19 MPH. ACC control module can be programmed using a scan tool so ECON is selected at other temperatures.
3. During air recirculation control programming, SID will display ACC: RECIRC ACC: SPEED CTRL. During air recirculation control program cancelling, SID will display ACC: RECIRC ACC: NORMAL CTRL. The ACC control module automatic default selection for air recirculation function will occur when vehicle speed is less than 6 MPH. Air recirculation function will disengage when vehicle speed is more than 19 MPH. In addition, vehicle speed must have exceeded 19 MPH at least once during trip for air recirculation function to activate. ACC control module can be programmed using a scan tool to automatically select air recirculation at other vehicle speeds.
4. During heated rear window control programming, SID will display ACC: AUTO RDEFR CTRL. During heated rear window control program cancelling, SID will display ACC: MANUAL RDEFR CTRL. The ACC control module automatic default request for electrically heated rear window and door mirrors function occurs 5 seconds after engine has been started when outside temperature is less than 41°F (5°C) and cabin temperature is less than 50°F (10°C). Heated rear window function will remain active for 2 minutes when outside temperature is 41°F (5°C) and up to 10 minutes when outside temperature is less than 14°F (-10°C).

BLOWER MOTOR DOES NOT OPERATE

1. Check for continuity between terminals of fuse No. 22 (40-amp), located in main fuse board. Main fuse board is located between instrument panel and driver's door. If fuse is okay, go to next step. If fuse is blown, replace fuse and recheck blower motor operation. If blower motor operates, repair is complete. If blower motor does not operate and fuse blows, repair short in Red wire between fuse No. 22 (40-amp) and blower motor. If blower motor does not operate and fuse is okay, go to step 8.
2. Disconnect blower motor 2-pin connector located on passenger-side of A/C-heater assembly. (Scheme 17) Connect a test light between ground and female side of blower motor 2-pin connector terminal No. 1 (Red wire). See «WIRING DIAGRAMS»(ref-97913-S32792199362001051400000). If test light comes on, go to next step. If test light does come on, repair open in Red wire and go to step 8.
3. Connect test light between female side of blower motor 2-pin connector terminal No. 1 (Red wire) and terminal No. 2 (Black wire). If test light comes on, go to next step. If test light does come on, repair suspect circuit and go to step 8.
4. Reconnect blower motor 2-pin connector. Using a fused (30-amp) jumper wire, backprobe blower motor 2-pin connector terminal No. 2 (Black wire) and connect to blower motor terminal No. 1 (Red/Brown wire). If blower motor operates at full speed, go to next step. If blower motor does not operate, replace blower motor. See «BLOWER MOTOR ASSEMBLY»(ref-97913-S04821551122001051400000) under REMOVAL & INSTALLATION. When repair is completed, go to step 8.
5. Turn ignition off. Disconnect blower motor speed control module 4-pin connector. (Scheme 17) Connect a test light between ground and speed control 4-pin connector terminal No. 3 (Orange/White wire). Turn ignition on. If test light comes on, go to next step. If test light does not come on, repair open in Orange/White wire between connector terminal No. 3 and ACC control module connector, and go to step 8.
6. Turn ignition off. Using a fused jumper wire, backprobe between ACC control module 39-pin connector terminal No. 1 (Black wire) and terminal No. 35 (White/Green wire). (Scheme 18) Connect a test light between blower motor speed control module 4-pin connector terminal No. 2 (Green/White wire) and terminal No. 3 (Orange/White wire). Turn ignition on. If test light comes on, go to next step. If test light does not come on, repair open in Green/White wire and go to step 8.
7. Turn ignition off. Disconnect ACC control module 39-pin connector. Ensure terminals and wiring are clean, tight and properly connected. (Scheme 18) If connector terminals and wiring are okay, go to «DTC B2425: BLOWER MOTOR CONTROL VOLTAGE»(ref-97913-S08706238452001051400000). If connector terminals and wiring are not okay, perform repairs as necessary and go to next step.
8. Using scan tool, clear all DTCs from all systems. Recheck A/C system operation for original complaint. If A/C system is operating properly and no DTC has been detected, repair is complete. If A/C system is not operating properly and/or a DTC has been detected, ACC control module may need to be replaced. See «CONTROL MODULES»(ref-97913-S40998985912001051400000) under SYSTEM TESTS.

Scheme 17

Scheme 18

NO OR INSUFFICIENT HEATING

Note. Vehicle is equipped with a vacuum controlled heater core shutoff valve. Vehicle may be equipped with an electric coolant circulation pump. Check for impurities in coolant and verify correct amount and mixture. Ensure that ACC control module is not user programmed. See ACC CONTROL MODULE PROGRAMMING under PROGRAMMING.

1. Turn ignition on and calibrate ACC control module. See «ACC CONTROL MODULE CALIBRATION»(ref-97913-S31322663742001051400000) under PROGRAMMING. Connect scan tool to Data Link Connector (DLC) located under instrument panel, below steering column. Using scan tool, contact ACC control module and read any stored DTCs. If no DTCs are stored, go to next step. If any DTCs are stored, go to «RETRIEVING DIAGNOSTIC TROUBLE CODES»(ref-97913-S01632241722001051400000) under SELF-DIAGNOSTICS. Perform repairs as necessary.
2. Using a vacuum pump, ensure heater core shutoff valve opens and closes properly and allows coolant to pass through it. (Scheme 15) If heater core shutoff valve operates properly, go to next step. Replace heater core shutoff valve if it does not operate properly. After repairs ensure ACC system operates properly.
3. If vehicle is equipped with coolant circulation pump, ensure pump is operating properly. (Scheme 14)and (Scheme 15). See «COOLANT CIRCULATION PUMP»(ref-97913-S11630002482001051400000) under SYSTEM TESTS. Perform repairs as necessary. After repairs, ensure ACC system operates properly. If vehicle is not equipped with coolant circulation pump, go to next step.
4. Start engine and allow to idle until thermostat opens and radiator/condenser cooling fans operate. Using scan tool, contact TRIONIC engine control module and read engine coolant temperature. Compare scan tool temperature with actual coolant temperature. Thermostat should open when coolant temperature is 188-196°F (87-91°C).
5. Radiator/condenser cooling fans should operate at low speed when coolant is 208-216°F (98-102°C). Radiator/condenser cooling fans should operate at high speed when coolant is 231-239°F (111-115°C). If thermostat and radiator/condenser cooling fans operate as specified, engine cooling system is operating properly. If thermostat and radiator/condenser cooling fans do not operate as specified, perform repairs as necessary.

NO OR INSUFFICIENT COOLING

Note. A/C compressor clutch engages but A/C system cooling is insufficient.

1. Ensure ambient temperature is more than 41°F (5°C) and that radiator/condenser cooling fans are operating properly. Check areas on both sides of A/C condenser and ensure they are clear, free of debris and have an adequate airflow. Ensure temperatures of receiver-drier inlet and outlet lines are the same. Using an A/C system manifold gauge set, ensure A/C system refrigerant operating pressures are within specifications. See «SPECIFICATIONS»(ref-97913-S36665738622001051400000). Perform repairs as necessary. If areas specified are okay, go to next step.
2. Start engine and allow to idle. Turn air recirculation on, select maximum heat for both zones and set blower motor to maximum speed. (Scheme 13) Close hood and all doors and windows. Operate A/C system for 5 minutes, ensuring A/C compressor operates continuously. If A/C compressor operates as specified, go to next step. If A/C compressor does operate as specified, go to step 10.
3. Using scan tool contact DICE control module and read EVAPORATOR TEMPERATURE. If indicated evaporator temperature is less than 50°F (10°C), go to next step. If indicated evaporator temperature is not less than 50°F (10°C), go to step 7.
4. Start engine and allow to idle. Select AUTO and maximum cooling for both zones. (Scheme 13) Check heater core return line temperature. If return line temperature does not decrease, go to next step. If return line temperature decreases, ensure mixed-air flap is operating properly and air filter and/or carbon filter are not clogged. Restricted fresh-air intake can diminish ACC system cooling capacity. When repairs are complete, go to step 12.
5. Check vacuum hoses between heater core shutoff valve, heater core shutoff valve control solenoid valve and intake manifold. (Scheme 14)and (Scheme 15). Repair hoses as necessary and go to step 12. If vacuum hoses are okay, go to next step.
6. Disconnect heater core shutoff valve control solenoid valve 2-pin connector. Turn ignition on. Connect a test light between ground and solenoid valve 2-pin connector terminal No. 1 (Violet wire). If test light comes on, go to step 12. If test light does not come on, repair open in Violet wire and go to step 12.
7. Check A/C system for refrigerant leaks. If no refrigerant leaks exist, go to next step. Repair any refrigerant leaks as necessary, evacuate and charge A/C system. Go to step 12.
8. Measure amount of refrigerant in system. See «SPECIFICATIONS»(ref-97913-S36665738622001051400000). If A/C system contains correct amount of refrigerant, replace expansion valve. See «EXPANSION VALVE»(ref-97913-S35642556882001051400000) under REMOVAL & INSTALLATION. Evacuate and charge A/C system and go to next step. If A/C system does not contain correct amount of refrigerant, evacuate and charge A/C system with correct amount of refrigerant. Go to 12.
9. Using scan tool, contact DICE control module. Read EVAPORATOR TEMPERATURE. If indicated value is less than 50°F (10°C), go to step 12. If indicated value is more than 50°F (10°C), replace A/C compressor clutch. See COMPRESSOR SERVICING article under GENERAL SERVICING. When repairs are complete, go to step 12.
10. Connect scan tool to Data Link Connector (DLC) located under instrument panel, below steering column. Using scan tool, contact TRIONIC engine control module and read engine COOLANT TEMPERATURE. Using scan tool, contact DICE control module and read A/C PRESSURE and EVAPORATOR TEMPERATURE. If indicated A/C condenser pressure is less than 392 psi (27.6 kg/cm 2 ), go to next step. If indicated evaporator temperature is less than 32°F (0°C), replace evaporator temperature sensor. See «EVAPORATOR TEMPERATURE SENSOR»(ref-97913-S10747369902001051400000) under REMOVAL & INSTALLATION. When repairs are complete, go to step 12. If scan tool indicated engine coolant temperature is more than 257°F (125°C), A/C compressor operation has been cancelled because of high coolant temperature. Ensure cooling system and engine coolant temperature sensor are operating properly. Perform repairs as necessary. When repairs are complete, go to step 12.
11. Connect A/C system manifold gauge set to A/C refrigerant system. With engine idling at normal operating temperature, read A/C PRESSURE using scan tool. If value displayed on scan tool and value displayed on high-side pressure gauge agree, repair A/C refrigerant system overcharge condition. Evacuate and charge A/C system, and ensure proper A/C operation. If value displayed on scan tool and value displayed on high-side pressure gauge do not agree, replace A/C pressure sensor. See «A/C PRESSURE SENSOR»(ref-97913-S05404597742001051400000) under REMOVAL & INSTALLATION. When repairs are complete, go to next step.
12. Using scan tool, clear all DTCs from all systems. Recheck A/C system operation for original complaint. If A/C system is operating properly and no DTC has been detected, repair is complete. If A/C system is not operating properly, or a DTC has been detected, a control module may need to be replaced. See «CONTROL MODULES»(ref-97913-S40998985912001051400000) under SYSTEM TESTS.

Fault Conditions

The following conditions may cause DTC to set

1. An open circuit or communication error between solar sensor and ACC control module.
2. When there are 5 consecutive periods without a solar sensor pulse pattern signal. Every 440 milliseconds ACC control module looks for a solar sensor signal. DTC will set when there are 5 consecutive periods without a solar sensor signal.
3. When a DTC is set, a default value is used by ACC control module. Default value used is the last valid value used.

A DTC will set if

1. There is an open or short to battery voltage between left mixed-air temperature sensor and ACC control module 39-pin connector terminal No. 19 (Brown/Orange wire). Voltage measured at ACC control module connector terminal No. 19 will be more than 4.9 volts.
2. There is a short to ground between left mixed-air temperature sensor and ACC control module. Voltage measured at terminal No. 19 is less than 0.1 volt.
3. There are 5 consecutive periods without a sensor signal. Every 440 milliseconds ACC control module looks for a sensor signal.
4. Mixed-air temperature sensor is out of range. See «MIXED-AIR TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS»(ref-97913-S32454995012001051400000) table. Measure sensor resistance between sensor terminals with sensor probe immersed in water.

MIXED-AIR TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS

A DTC will set if

1. There is an open or short to battery voltage indicated between cabin temperature sensor and ACC control module 39-pin connector terminal No. 20 (Orange/White wire). Voltage measured at ACC control module terminal No. 20 will be more than 4.9 volts.
2. There is a short to ground indicated between cabin temperature sensor and ACC control module 39-pin connector terminal No. 20. Voltage measured at terminal No. 20 is less than 0.1 volt.
3. There are 5 consecutive periods without a cabin temperature signal. Every 440 milliseconds the ACC control module looks for a cabin temperature sensor signal.
4. Cabin temperature sensor is out of range. See «CABIN TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS»(ref-97913-S22046049182001051400000) table. Measure sensor resistance between sensor terminals with sensor probe immersed in water.

CABIN TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS

A DTC will set

1. When current on an ACC control module stepping motor output exceeds a certain value. DTC set will be for a short circuit.
2. When current on an ACC control module stepping motor output is less than 55 mA. DTC set will be for an open circuit.
3. During ACC control module monitoring and calibration, if a malfunction is detected.

A loose flap DTC will set

1. When ACC control module moves stepping motor toward an end position and stepping motor continues more than 20 percent past expected position.
2. If ACC control module has not been calibrated.
3. During monitoring and calibration, if a malfunction is detected.

A DTC will set

1. When stepping motor is operating within a 10-90 percent range and ACC control module detects excessive voltage usage. Mixed-air stepping motor operating range is considered to be 0-100 percent.
2. If ACC control module has not been calibrated.
3. During monitoring and calibration, if a malfunction is detected.

A DTC will set if

1. There is an open or short to battery voltage between right mixed-air temperature sensor and ACC control module 39-pin connector terminal No. 18 (Brown/Red wire). Voltage measured at connector terminal No. 18 will be more than 4.9 volts.
2. There is a short to ground between right mixed-air temperature sensor and ACC control module 39-pin connector terminal No. 18. Voltage measured at connector terminal No. 18 is less than 0.1 volt.
3. There are 5 consecutive periods without a mixed-air temperature sensor signal. Every 440 milliseconds ACC control module looks for a mixed-air temperature sensor signal.
4. Mixed-air temperature sensor is out of range. See «MIXED-AIR TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS»(ref-97913-S14259124342001051400000) table. Measure sensor resistance between sensor terminals with sensor probe immersed in water.

MIXED-AIR TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS

A DTC will set if

1. There is a short to ground between evaporator temperature sensor 2-pin connector terminal No. 1 and Dashboard Integrated Central Electronics (DICE) control module 70-pin connector terminal No. 10 (Blue/White wire).
2. There is an open or short to battery voltage between evaporator temperature sensor 2-pin connector terminal No. 2 and DICE control module 70-pin connector terminal No. 30 (Green/Red wire on 2000 models; Red/Green wire on 2001 models).
3. Evaporator temperature sensor is out of range. See «EVAPORATOR TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS»(ref-97913-S08322112522001051400000) table. Measure sensor resistance between sensor terminals with senor probe immersed in ice water.

EVAPORATOR TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS

A DTC will set if

1. There is a short to ground detected at DICE control module 70-pin connector terminal No. 9 (Blue/Green wire on 2000 models; Green/Blue wire on 2001 models).
2. Voltage detected at DICE control module connector terminal No. 9 is less than normal range.
3. There is an open or short to battery voltage detected at DICE control module connector terminal No. 9.
4. Voltage detected at DICE control module connector terminal No. 9 is more than normal range.
5. Evaporator A/C pressure sensor is out of range. See «A/C PRESSURE SENSOR VOLTAGE»(ref-97913-S27584208222001051400000) table. Measure sensor voltage with connector connected by backprobing terminals.

A/C PRESSURE SENSOR VOLTAGE

A DTC will set if

1. A short to battery voltage is detected when heater core shutoff valve solenoid is activated. Voltage detected at ACC control module 39-pin connector terminal No. 24 (White/Green wire on 2000 models; Green/White wire on 2001 models) is more than 6 volts.
2. A short to ground is detected when heater core shutoff valve solenoid is not activated. Voltage detected at ACC control module connector terminal No. 24 is more than 6 volts.
3. There are 5 consecutive voltage measurements (one every 440 milliseconds).

A DTC will set if

1. A short to battery voltage is detected when circulation pump is activated. Voltage detected at ACC control module 39-pin connector terminal No. 23 (White wire) is more than 6 volts.
2. A short to ground is detected when circulation pump is not activated. Voltage detected at ACC control module connector terminal No. 23 is more than 6 volts.
3. There are 5 consecutive voltage measurements (one every 440 milliseconds).

A DTC will set

1. When current on an ACC control module stepping motor output exceeds a certain value. DTC set will be for a short circuit.
2. When current on an ACC control module stepping motor output is less than 55 mA. DTC set will be for an open circuit.
3. During ACC control module monitoring and calibration, if a malfunction is detected.

A loose flap DTC will set

1. When ACC control module moves stepping motor toward an end position and stepping motor continues more than 20 percent past expected position.
2. If ACC control module has not been calibrated.
3. During ACC control module monitoring and calibration, if a malfunction is detected.

A DTC will set

1. When stepping motor is operating within a 10-90 percent range and ACC control module detects excessive voltage usage. Air distribution flap stepping motor operating range is considered to be 0-100 percent. During stepping motor operation ACC control module monitors stepping motor voltage use.
2. If ACC control module has not been calibrated.
3. During monitoring and calibration, if a malfunction is detected.

A DTC will set

1. When a short to battery voltage is indicated between air recirculation motor and ACC control module, and air recirculation motor is not activated. Voltage measured at 39-pin connector terminal No. 21 (Green/White wire) will be more than 9 volts.
2. When a short to ground or open is indicated between air recirculation motor and ACC control module, and air recirculation motor is not activated. Voltage measured at connector terminal No. 21 will be less than 3 volts.
3. There are 5 consecutive voltage measurements (one every 440 milliseconds).

A DTC will set if a short to ground or battery voltage is detected.

A DTC will set

1. When current on an ACC control module stepping motor output exceeds a certain value. DTC set will be for a short circuit.
2. When current on an ACC control module stepping motor output is less than 55 mA. DTC set will be for an open circuit.
3. During ACC control module monitoring and calibration, if a malfunction is detected.

A DTC will set

1. When ACC control module moves stepping motor toward an end position and stepping motor continues more than 20 percent past expected position.
2. If ACC control module has not been calibrated.
3. During ACC control module monitoring and calibration, if a malfunction is detected.

A DTC will set

1. When stepping motor is operating within a 10-90 percent range and ACC control module detects excessive voltage usage. Air distribution flap stepping motor operating range is considered to be 0-100 percent.
2. If ACC control module has not been calibrated.
3. During monitoring and calibration, if a malfunction is detected.

A DTC will set

1. When voltage measured at ACC control module 39-pin connector terminals No. 36 (Blue/Red wire on 2000 models; Red/Blue wire on 2001 models), No. 37 (Violet wire), No. 38 (Brown/White wire) or No. 39 (Yellow/White wire) is more than 0.4 volt.
2. During monitoring, if a malfunction is detected. ACC control module measures voltage every 40 milliseconds.

A/C SYSTEM PERFORMANCE

1. Ensure ambient temperature is 68-77°F (20-25°C). Attach manifold gauge set to A/C system. Ensure all panel outlets are open. Insert thermometer 2" (50 mm) into center panel outlet. Close hood and all doors and windows. Start engine and operate at 1500-2000 RPM.
2. Select maximum blower motor speed. Select LO temperature as displayed on ACC control panel. Select panel mode control. (Scheme 13) After 5 minutes of A/C system operation, center panel outlet temperature should be less than 45°F (7°C).

Note. Coolant circulation pump is not used on all vehicles.

1. Disconnect coolant circulation pump 2-pin connector. Connect a test light between ground and pump connector terminal No. 2 (Red wire). If test light comes on, go to next step. If test light does not come on, repair open or short in Red wire between pump and fuse No. 20 (15-amp).
2. Connect test light between coolant circulation pump connector terminals. If test light comes on, go to next step. If test light does not come on, repair open White wire between pump and ACC control module 39-pin connector terminal No. 23.
3. Using a fused jumper wire, connect battery voltage to pump terminal No. 2. Using another jumper wire, ground pump terminal No. 1. If pump operates, replace ACC control module. See «CONTROL MODULES»(ref-97913-S40998985912001051400000). Replace coolant circulation pump if it does not operate. (Scheme 14) Ensure ACC system operates properly.

CONTROL MODULES

Manufacturer has found many control modules that have been replaced were not the cause of the problem and replacement of the control module did not correct the problem. Upon examination, these control modules were found to be free of defects. Before replacing a suspect control module, perform the following

1. Control modules are sensitive to static electricity. Before touching a control module touch a ground point. Never touch control module pins.
2. Connect test light, DVOM, or scan tool and wiggle wiring harness at several points and in different directions to detect intermittent opens and/or shorts. See «WIRING DIAGRAMS»(ref-97913-S32792199362001051400000) . Preform repairs as necessary and recheck.
3. Ensure all control module power supply circuits are okay.
4. Ensure all control module ground connections are clean and tight.
5. Using a scan tool or DVOM, ensure control module input and output signal values okay. If replacing ACC control module, see «ACC CONTROL MODULE PIN VOLTAGE TEST»(ref-97913-S02195814432001051400000) under SYSTEM TESTS. Before replacing a TRIONIC engine control module or DICE control module, see appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
6. Before replacing ACC control module, ensure that all user programming has been cleared. See «ACC CONTROL MODULE PROGRAMMING»(ref-97913-S20981095972001051400000) under PROGRAMMING.
7. Using a scan tool, ensure that all functions are operating properly. A fault in one output signal may affect another output signal.
8. If problem continues, replace ACC control module with a known-good control module and recheck. Replace ACC control module if problem is corrected. See «ACC CONTROL MODULE»(ref-97913-S38588013282001051400000) under REMOVAL & INSTALLATION.

A/C-HEATER UNIT