Heating, Ventilation & Air Conditioning: Overview Hyundai Elantra IV

OIL RETURN OPERATION

There is close affinity between the oil and the refrigerant. During normal operation, part of the oil recirculates with the refrigerant in the system. When checking the amount of oil in the system, or replacing any component of the system, the compressor must be run in advance for oil return operation. The procedure is as follows

1. Open all the doors and the engine hood.
2. Start the engine and air conditioning switch to "ON" and set the blower motor control knob at its highest position.
3. Run the compressor for more than 20 minutes between 800 and 1,000 rpm in order to operate the system.
4. Stop the engine.

DESCRIPTION

The A/C pressure transducer converts the pressure value of the high pressure line into a voltage value after measurement. By a converted voltage value the ECU controls the cooling fan by operating it at high or low speed. The ECU stops the compressor operation when the temperature of the refrigerant line is too high or too low.

Scheme 16

1. Measure the pressure of high pressure line by measuring voltage output between NO.1 and NO.2 terminals. see scheme 30: Identifying A/C Pressure Transducer Connector Terminal
2. Inspect the voltage value whether it is sufficient to be regular value or not. Voltage = 0.00878835 * Pressure + 0.37081095 [PSIA]
3. If the measured voltage value is not specification, replace the A/C pressure transducer.

Scheme 17

1. Disconnect the negative (-) battery terminal.
2. Recover the refrigerant with a recovery/charging station.
3. Disconnect A/C pressure transducer connector (3P) (A).
4. Remove the A/C pressure transducer (B). (Scheme 16): Identifying A/C Pressure Transducer And Connector CAUTION: Take care that liquid & suction pipe are not bent.
5. Installation is the reverse order of removal. TORQUE: 10~12N.m (1.0~1.2kgf.m, 7.4~8.8lbf.ft)

The evaporator temperature sensor will detect the evaporator core temperature and interrupt compressor relay power in order to prevent evaporator freezing by excessive cooling.

It is a negative type thermistor whose resistance is inversely proportional to temperature.

Scheme 18

1. Ignition "OFF"
2. Disconnect evaporator temperature sensor.
3. Using the multi-tester, Measure resistance between terminal "1" and "2" of evaporator temperature sensor. (Scheme 17): Measuring Resistance Between Terminal Of Evaporator Temperature Sensor SPECIFICATION TEMPERATURE SPECIFICATION Evaporator core temperature [°C (°F)] Resistance [kohms] -10 (14) 43.35 0 (32) 27.62 10 (50) 18.07 15 (59) 14.75 30 (86) 8.30 40 (104) 5.71 50 (122) 4.15
4. If the measured resistance is not specification, substitute with a known-good evaporator temperature sensor and check for proper operation.
5. If the problem is corrected, replace the evaporator temperature sensor.

Scheme 19

Scheme 20

1. Disconnect the evaporator sensor connector (A).
2. Remove the evaporator temperature sensor (B), by pulling it after rotating 90° in a counter clock wise direction. (Scheme 19): Identifying Evaporator Sensor Connector And Temperature Sensor
3. Installation is the reverse order of removal

1. In-car air temperature sensor is located at the crash pad.
2. The sensor contains thermistor which measures the temperature of the inside. The signal decided by the resistance value which changes in accordance with perceived inside temperature, is delivered to heater control unit and according to this signal the control unit regulates incar temperature to intended value.
3. It perceives the inside temperature, changes the resistance value, and enters the corresponding voltage into the automatic temperature control module.
4. It is used for discharge temperature control, sensor failsafe, temperature door control, blower motor level control, and A/C auto control.

Scheme 21

1. The photo sensor (A) is located at the center of defrost nozzle.
2. The photo sensor contains a photo voltaic (sensitive to sunlight) diode. The solar radiation received by its light receiving portion, generates an electromotive force in proportion to the amount of radiation received which is transferred to the automatic temperature control module so that the solar radiation compensation will be performed.

1. Water temperature sensor is located at the heater unit.
2. It detects coolant temperature. Its signal is used for cold engine lockout control. When the driver operates the heater before the engine is warmed up, the signal from sensor causes the heater control unit to reduce blower motor speed until coolant temperature reaches the threshold value.

Scheme 22

Scheme 23

1. Ignition "ON"
2. Using the multi-tester, Measure resistance between terminal "1" and "2" of water temperature sensor. (Scheme 22): Measuring Resistance Between Terminal Of Water Temperature Sensor SPECIFICATION TEMPERATURE SPECIFICATION Coolant temperature [°C (°F)] Resistance (kohms) Voltage (V) -10 (14) 55.85 ± 3% 4.24 ± 3% 0 (32) 32.91 ± 3% 3.83 ± 3% 10 (50) 19.99 ± 3% 3.33 ± 3% 20 (68) 12.51 ± 3% 2.78 ± 3% 30 (86) 8.047 ± 3% 2.23 ± 3% 40 (104) 5.311 ± 3% 1.73 ± 3% 50 (122) 3.588 ± 3% 1.32 ± 3% 60 (140) 2.476 ± 3% 0.99 ± 3% 70 (158) 1.742 ± 3% 0.74 ± 3% 80 (176) 1.246 ± 3% 0.55 ± 3%
3. If the measured resistance is not specification, substitute with a known-good water temperature sensor and check for proper operation.
4. If the problem is corrected, replace the water temperature sensor.

Note. Negative type thermistor that resistance will rise with lower temperature, and reduce with higher temperature.

Scheme 24

Scheme 25

Scheme 26

1. Disconnect the negative (-) battery terminal.
2. Remove the crash pad lower cover (A). (Refer to «CRASH PAD»(ref-287418-S12947596922008061200000) ) (Scheme 23): Identifying Crash Pad Lower Cover
3. Disconnect the connector (A) of water temperature sensor and then remove the water temperature sensor (B) by pulling out. (Scheme 24): Identifying Water Temperature Sensor Connector (Scheme 25): Identifying Water Temperature Sensor
4. Installation is the reverse order of removal.

Note. Take care that wire of water temperature sensor is not to be damaged. Apply caulk to the water temperature sensor. Make sure that there is no air leakage

1. The ambient temperature sensor is located at the front of the condenser and detects ambient air temperature. It is a negative type thermistor; resistance will increase with lower temperature, and decrease with higher temperatures.
2. The sensor output will be used for discharge temperature control, temperature regulation door control, blower motor level control, mix mode control and in-car humidity control.

Note. If the ambient temperature is below 2.0°C (35.6°F), the A/C compressor will be stopped. The compressor will be operated by manual operating.

Scheme 27

Scheme 28

1. Ignition "OFF"
2. Disconnect ambient temperature sensor.
3. Check the resistance of ambient temperature sensor between terminals 1 and 2 whether it is changed by changing of the ambient temperature. (Scheme 26): Identifying Ambient Temperature Sensor (Scheme 27): Identifying Ambient Temperature Sensor Connector Terminals [SPECIFICATION TEMPERATURE SPECIFICATION Temperature (°C) Resistance (kohms ± 3%) -20 290.17 -10 165.79 0 97.83 10 59.67 20 37.47 30 24.17 40 15.99 50 10.82
4. If the measured resistance is not specification, substitute with a known-good ambient temperature sensor and check for proper operation.
5. If the problem is corrected, replace the ambient temperature sensor.

1. A.Q.S is located at center support in front of the engine radiator, and detects hazardous elements in ambient air providing output signal to control.
2. It will detect sulfurous acid gas, carbon dioxide, carbon monoxide, hydrocarbon and allergen.

1. Heater unit includes mode control actuator and temperature control actuator.
2. Temperature control actuator is located at the heater unit. It regulates the temperature by the procedure as follows. Signal from control unit adjusts position of temperature door by operating temperature switch and then temperature will be regulated by the hot/cold air ratio decided by position of temperature door.

Scheme 29

1. Ignition "OFF"
2. Disconnect the connector of temperature control actuator.
3. Verify that the temperature control actuator operates to the hot position when connecting 12V to the terminal 3 and grounding terminal 4. Verify that the temperature control actuator operates to the cool position when connecting in the reverse. see scheme 60: Identifying Temperature Control Actuator Connector Terminal
4. Check the voltage between terminals 6 and 7. SPECIFICATION VOLTAGE SPECIFICATION Door position Voltage (6-7) Error detecting Max. cooling 0.3 ± 0.15V Low voltage: 0.1V or less Max. heating 4.7 ± 0.15V High voltage: 4.9V or more It will feedback current position of actuator to controls.
5. If the measured voltage is not specification, substitute with a known-good temperature control actuator and check for proper operation.
6. If the problem is corrected, replace the temperature control actuator.

Scheme 30

1. Disconnect the negative (-) battery terminal.
2. Remove the driver's crash pad lower panel (Refer to «CRASH PAD»(ref-287418-S12947596922008061200000) ).
3. Disconnect the temperature control actuator connector after removing the air duct.
4. Loosen the mounting screw and then remove the temperature control actuator (B). (Scheme 29): Identifying Temperature Control Actuator And Mounting Screws
5. Installation is the reverse order of removal.

Scheme 31

The mode control actuator is located at the heater unit. It adjusts position of mode door by operating mode control actuator based on signal of A/C control unit. Pressing mode select switch makes the mode control actuator shift in order of vent--> B/L --> floor --> mix.

Scheme 32

1. Ignition "OFF"
2. Disconnect the connector of mode control actuator.
3. Verify that the mode control actuator operates to the defrost mode when connecting 12V to the terminal 3 and grounding terminal 4.
4. Verify that the mode control actuator operates to the vent mode when connecting in the reverse. (Scheme 31): Identifying Mode Control Actuator Connector Terminal
5. Check the voltage between terminals 5 and 6. VOLTAGE SPECIFICATION Door position Voltage (5-6) Error detecting Vent 0.3 ± 0.15V Low voltage; 0.1V or less Defrost 4.7 ± 0.15V High voltage: 4.9V or more It will feedback current position of actuator to controls.
6. If the measured voltage is not with in specification, substitute with a known-good mode control actuator and check for proper operation.
7. If the problem is corrected, replace the mode control actuator.

Scheme 33

1. Disconnect the negative (-) battery terminal.
2. Remove the driver's crash pad lower panel. (Refer to «CRASH PAD»(ref-287418-S12947596922008061200000) )
3. Disconnect the mode control actuator connector after removing the air duct.
4. Loosen the mounting screws and then remove the mode control actuator (B). (Scheme 32): Identifying Mode Control Actuator And Mounting Screws
5. Installation is the reverse order of removal.

Identifying Blower Unit Components. Scheme 34

This has particle filter which eliminates foreign materials and odor. The particle filter includes odor filter as well as conventional dust filter to ensure comfortable interior environment.

Scheme 35

Scheme 36

1. Open the glove box (A). Lower the glove box down completely by removing the glove box stopper (B) to the glove box. see scheme 78: Identifying Glove Box And Glove Box Stopper
2. Remove the filter cover (A) with pushing the knob.
3. Replace the air filter (B), install it after making sure of the direction of air filter. (Scheme 35): Identifying Filter Cover And Air Filter NOTE: In case of driving in an air-polluted area or rugged terrain, check and replace the air filter as frequently as possible. Replacement period: 15,000 km (9320 mile)

Scheme 37

1. The intake actuator is located at the blower unit.
2. It regulates the intake door by signal from control unit.
3. Pressing the intake selection switch will shift between recirculation and fresh air modes.

Scheme 38

1. Ignition "OFF"
2. Disconnect the intake actuator connector.
3. Verify that the actuator operates to the recirculation position when connecting 12V to the terminal 3 and grounding terminal 4.
4. Verify that the intake actuator operates to the fresh position when connecting in the reverse. (Scheme 37): Identifying Intake Actuator Connector Terminal VOLTAGE SPECIFICATION Door position Voltage (5-6) Error detecting Recirculation 0.3 ± 0.15V Low voltage: 0.1V or less Fresh 4.7 ± 0.15V High voltage: 4.9V or more
5. If the intake actuator is not operated well, substitute with a known-good intake actuator and check for proper operation.
6. If the problem is corrected, replace the intake actuator.

Scheme 39

1. Disconnect the negative (-) battery terminal.
2. Remove the glove box (Refer to «CRASH PAD»(ref-287418-S12947596922008061200000) ).
3. Disconnect the intake actuator connector.
4. Loosen the mounting screw and then remove the intake actuator (A) from the blower unit. (Scheme 38): Identifying Intake Actuator
5. Installation is the reverse order of removal.

Scheme 40

CONNECTOR PIN FUNCTION

CONNECTOR PIN FUNCTION CHART

Scheme 41

Scheme 42

Scheme 43

Scheme 44

1. Disconnect the negative (-) battery terminal.
2. After disconnect the mounting clip, remove the center fascia panel (A). (Scheme 40): Identifying Center Fascia Panel
3. After loosening the mounting screw, remove the center fascia lower panel (A). (Scheme 41): Identifying Center Fascia Lower Panel With Mounting Screw
4. Remove the heater & A/C controller (A) after loosening 4 screws. (Scheme 42): Identifying Heater & A/C Controller With Screws
5. Disconnect the connectors (A) from the center fascia. (Scheme 43): Identifying Center Fascia Connectors
6. Installation is the reverse order of removal.

Scheme 45

CONNECTOR PIN FUNCTION

CONNECTOR PIN FUNCTION CHART

Scheme 46

Scheme 47

Scheme 48

Scheme 49

1. Self-diagnosis process The F.A.T.C. module self test feature will detect electrical malfunction and provide error codes for system components with suspected failures. (Scheme 45): Self-Diagnosis Procedure Chart NOTE: DTC data can be retrieved from the control panel directly or from the DLC using the Hi-Scan Pro.
2. How to read self-diagnostic code After the display panel flickers three times every 0.5 second, the corresponding fault code flickers on the setup temperature display panel every 0.5 second and will show two figures. Codes are displayed in numerical format FAULT CODE FAULT CODE CHART Fault code Fail description Control unit 0 Normal 11 In-car temperature sensor open (High) 12 In-car temperature sensor short (Low) 13 Ambient temperature sensor open (High) 14 Ambient temperature sensor short (Low) 15 Water temperature sensor open (High) 16 Water temperature sensor short (Low) 17 Evaporator temperature sensor open (High) 18 Evaporator temperature sensor short (Low) 19 Air mix potentiometer open (Low) - Driver 19 Air mix potentiometer short (High) - Driver 20 Air mix motor (Driver) 21 Direction potentiometer open (Low) - Driver 21 Direction potentiometer short (High) - Driver 22 Direction control motor (Driver) 23 Humidity sensor open (High) 24 Humidity sensor short (Low) DIAGNOSTIC TROUBLE CODE DTC (LIST) DTC Description «B1202»(ref-287428-S10973689932008061200000) WATER TEMPERATURE SENSOR OPEN (HIGH) «B1203»(ref-287428-S41633933172008061200000) WATER TEMPERATURE SENSOR SHORT (LOW) «B1208»(ref-287428-S13614540432008061200000) INTAKE POTENTIOMETER OPEN «B1209»(ref-287428-S09793683792008061200000) INTAKE POTENTIOMETER SHORT «B1233»(ref-287428-S22193199972008061200000) IN-CAR TEMPERATURE SENSOR SHORT (LOW) «B1234»(ref-287428-S04587655832008061200000) IN-CAR TEMPERATURE SENSOR OPEN (HIGH) «B1237»(ref-287428-S35772143552008061200000) AMBIENT TEMPERATURE SENSOR SHORT (LOW) «B1238»(ref-287428-S26708466462008061200000) AMBIENT TEMPERATURE SENSOR OPEN (HIGH) «B1241»(ref-287428-S18978924962008061200000) EVAPORATOR TEMPERATURE SENSOR SHORT (LOW) «B1242»(ref-287428-S31793554482008061200000) EVAPORATOR TEMPERATURE SENSOR OPEN (HIGH) «B1245»(ref-287428-S41940837452008061200000) AIR MIX POTENTIOMETER OPEN (LOW) «B1246»(ref-287428-S37991488032008061200000) AIR MIX POTENTIOMETER SHORT (HIGH) «B1249»(ref-287428-S42586104612008061200000) DIRECTION POTENTIOMETER OPEN (LOW) «B1250»(ref-287428-S07109902062008061200000) DIRECTION POTENTIOMETER SHORT (HIGH) «B1257»(ref-287428-S23531724492008061200000) AQS OPEN «B1258»(ref-287428-S23945073852008061200000) AQS SHORT «B1259»(ref-287428-S25069064512008061200000) AQS FAILURE «B2406»(ref-287428-S16654050192008061200000) AIR MIX MOTOR (DRIVER) «B2408»(ref-287428-S35168031872008061200000) INTAKE MOTOR FAILURE «B2409»(ref-287428-S15078520172008061200000) DIRECTION CONTROL MOTOR
3. Fault code display Continuance operation: DTC code is one. (Scheme 46): Fault Code Display - Continuance Operation DTC Code One Continuance operation: DTC code is more two. (Scheme 47): Fault Code Display - Continuance Operation DTC Code More Two STEP operation Normal or one fault code is same as a continuance operation. DTC code is more two. (Scheme 48): Fault Code Display - Step Operation If fault codes are displayed during the check, inspect malfunction causes by referring to fault codes. Fail safe In-car temperature sensor: Control with the value of 25°C (77°F) Ambient temperature sensor: Control with the value of 20°C (67°F) Evaporator temperature sensor: Control with the value of -2°C (28.4°F) Humidity sensor: Control with the value of 10% Photo sensor: Control with the value of 0 w/m 2 Temperature control actuator (Air mix potentiometer): If temperature set 17°C-24.5°C, fix at maximum cooling position. If temperature set 25°C-32°C, fix at maximum heating position. Mode control actuator (Direction potentiometer): Fix vent position, while selecting vent mode. Fix defrost position, while selecting all except vent mode. A.Q.S sensor: AQS operation OFF. Intake position: the position before selecting AQS switch. Water temperature sensor: control with the value of -2°C (28.4°F) Intake control actuator Fix FRE position, while selecting FRE mode. Fix REC position, while selecting REC mode.

GENERAL DESCRIPTION

A water temp, sensor located at heater unit, detects coolant temperature. Its signal is used for cold engine lockout control. When the driver operates the heater before the engine is warmed up, the signal from sensor causes the heater control unit to reduce blower motor speed until coolant temperature reaches the threshold value.

DTC DESCRIPTION

The A/C controller sets DTC B1202 if there is an open circuit in water temp, sensor signal harness or the measured resistance value of the sensor is more than the threshold value (about 176.3kohms)

Refer to DTC B1202 .

The A/C controller sets DTC B1203 if there is a short circuit in water temp, sensor signal harness or the measured resistance value of sensor is less than threshold value (about 1.2kohms)

Intake door located at heater unit controls the inlet of car. When driver operates the intake switch, A/C controller recirculation mode signal from intake switch and operates intake door actuator to turn intake door to intended position, (with fresh mode signal, intake door is closed and with fresh mode signal, intake door is opened).

The A/C controller sets DTC B1208 if there is an open circuit or poor connection in the intake potentiometer.

Refer to DTC B1208 .

The A/C controller sets DTC B1209 if there is a short to power in the Intake potentiometer.

The incar temperature sensor located at crush pad, control unit contains a thermistor which measures the temperature of the inside. The signal, decided by the resistance value which changes in accordance with perceived inside temperature, is delivered to heater control unit and according to this signal, the control unit regulates incar temperature to intended value.

The A/C controller sets DTC B1233 if there is a short circuit in incar temp, sensor signal harness or the measured resistance value of sensor is less than threshold value (about 7.46kohms)

Refer to DTC B1233 .

The A/C controller sets DTC B1234 if there is an open circuit in incar temp, sensor signal harness or the measured resistance value of sensor is more than threshold value (about 509.57kohms)

The ambient temperature senor located at the center stay of the condenser, detects ambient air temperature. It is a negative type thermistor whose resistance is inversely proportional to temperature. Its output is used for discharge temperature sensor, sensor fail-safe, temperature regulation door lock, blower motor level control, mix mode control and in-car humidity control.

The A/C controller sets DTC B1237 if there is a short circuit in ambient temp, sensor signal harness or the measured resistance value of sensor is less than threshold value (about 7.48kohms)

Refer to DTC B1237 .

The A/C controller sets DTC B1238 if there is an open circuit in ambient temp, sensor signal harness or the measured resistance value of sensor is more than threshold value (about 527kohms)

The Evaporator temperature sensor located on heater unit, detects the core temperature and interrupts compressor relay power, in order to prevent evaporator freezing by excessive cooling. It is a negative type thermistor whose resistance is inversely proportional to temperature.

The A/C controller sets DTC B1241 if there is a short circuit in evaporator temp, sensor signal harness or the measured resistance value of sensor is less than threshold value (about 0.9kohms)

Refer to DTC B1241 .

The A/C controller sets DTC B1242 if there is an open circuit in evaporator temp, sensor signal harness or the measured resistance value of sensor is more than threshold value (about 13.6kohms)

Temperature control actuator located at heater unit, regulates the temperature by the procedure as follows. Signal from control unit adjusts position of temp, door by operating temp, motor and then temperature will be regulated by the hot/cold air ratio decided by position of temp. door.

The A/C controller sets DTC B1245 if there is an open circuit or poor connection in the air mix potentiometer.

Refer to DTC B1245 .

The A/C controller sets DTC B1246 if there is a short to power in the air mix potentiometer.

The mode control actuator mounted on heater unit, adjusts position of mode door by operating Direction Motor based on signal of A/C control unit. Pressing mode select switch makes the mode control actuator shift in order of vent --> B/L --> floor --> mix.

The A/C controller sets DTC B1249 if there is an open circuit or poor connection in the Direction potentiometer.

Refer to DTC B1249 .

The A/C controller sets DTC B1250 if there is a short to power in the Direction potentiometer.

AQS (Air Quality System) keeps air inside in the most suitable state for driver. In polluted area AQS detects hazardous gas and intercepts inflow automatically, Inversely, In fresh area it allows the inflow of air to prevent the shortage of air and the accumulation of carbon dioxide. AQS sensor is located at front side of condenser and once hazardous gas is detected, it delivers the voltage signal to A/C controller for closing intake door.

The A/C controller sets DTC B1257 if there is an open circuit in AQS sensor signal harness or the measured voltage value of sensor is more than threshold value.

Refer to DTC B1257 .

The A/C controller sets DTC B1258 if there is a short circuit in AQS sensor signal harness or the measured voltage value of the sensor is less than the threshold value.

Refer to DTC B1257 .

The A/C controller sets DTC B1259 if preheating time of AQS sensor is over 40sec or signal from AQS sensor is not within specifications.

Temperature control actuator located at heater unit, regulates the temperature by the procedure as follows. Signal from control unit adjusts position of temp, door by operating temp, motor and then temperature will be regulated by the hot/cold air ratio decided by position of temp. door.

The A/C controller sets DTC B2406 if the air mix actuator doesn't move to intended position within 40sec (In this case, A/C controller try to move temp, door for 2sec. 3 times, every 20 sec. before setting DTC).

Intake door located at heater unit controls the inlet of car. When driver operates the intake switch, A/C controller recirculation mode signal from intake switch and operates intake door actuator to turn intake door to intended position, (with fresh mode signal, intake door is closed and with fresh mode signal, intake door is opened.

The A/C controller sets DTC B2408 if the intake motor Doesn't move to intended position within 40sec (The A/C controller attempts to move the intake door for a 2 second duration at a frequency of 3 times every 20 seconds before storing a DTC.)

The mode control actuator mounted on heater unit, adjusts position of mode door by operating Direction Motor based on signal of A/C control unit. Pressing mode select switch makes the mode control actuator shift in order of vent --> B/L --> floor --> mix.

The A/C controller sets DTC B2409 if the direction motor doesn't move to intended position within 40sec (In this case, A/C controller try to move mode door for 2sec. 3 times, every 20 sec. before setting DTC).