SAFETY PRECAUTIONS
| WARNING | Wear safety goggles and gloves when servicing the refrigeration system to prevent severe damage to eyes and hands. |
Because R-134a refrigerant is a hydro fluorocarbon (HFC) which contains hydrogen atoms in place of chlorine atoms, it will not cause damage to the ozone layer.
Ozone filters out harmful radiation from the sun. To assist in protecting the ozone layer, Mitsubishi Motors Corporation recommends an R-134a refrigerant recycling device.
Refrigerant R-134a is transparent and colorless in both the liquid and vapor state. Since it has a boiling point of - 29.8°C (-21.64°F) at atmospheric pressure, it will be a vapor at all normal temperatures and pressures. The vapor is heavier than air, non-flammable, and non-explosive. The following precautions must be observed when handling R-134a.
| WARNING | Do not heat R-134a above 40°C (104.0°F) or it may catch fire and explode. |
R-134a evaporates so rapidly at normal atmospheric pressures and temperatures that it tends to freeze anything it contacts. For this reason, extreme care must be taken to prevent any liquid refrigerant from contacting the skin and especially the eyes. Always wear safety goggles when servicing the refrigeration part of the A/C system. Keep a bottle of sterile mineral oil handy when working on the refrigeration system.
- If any liquid refrigerant gets into your eyes, use a few drops of mineral oil to wash them out. R-134a is rapidly absorbed by the oil.
- Next, splash your eyes with plenty of cold water.
- Call your doctor immediately even if irritation has ceased.
| CAUTION | Keep R-134a containers upright when charging the system. |
In most instances, moderate heat is required to bring the pressure of the refrigerant in its container above the pressure of the system when charging or adding refrigerant.
A bucket or large pan of hot water not over 40°C (104.0°F) is all the heat required for this purpose. Do not heat the refrigerant container with a blow torch or any other means that would raise temperature and pressure above this temperature. Do not weld or steam-clean on or near the system components or refrigerant lines.
| WARNING | A leak detector for R-134a should be used to check for refrigerant gas leaks. |
| CAUTION | Do not allow liquid refrigerant to touch bright metal or it will be stained. |
When metering R-134a into the refrigeration system, keep the supply tank or cans in an upright position. If the refrigerant container is on its side or upside down, liquid refrigerant will enter the system and damage the compressor.
Refrigerant will tarnish bright metal and chrome surfaces, and in combination with moisture can severely corrode all metal surfaces.
CONDENSER FAN AND RADIATOR FAN CONTROL
The ECM < M/T > or PCM < A/T > judges the required revolution speed of radiator fan motor and condenser fan motor using the input signals transmitted from A/C switch, output shaft speed sensor and engine coolant temperature sensor. The PCM activates the fan control relays to drive the radiator fan motor and condenser fan motor.
When operating the air conditioning switch
- The air thermo sensor, which senses the temperature of the air flowing out of the evaporator, deactivates the compressor at 3°C (37.4°F) or below.
- The dual pressure switch turns OFF when the refrigerant pressure becomes excessively high or low, thus protecting the compressor circuit (See «A/C COMPRESSOR CLUTCH RELAY ON CONDITIONS»(ref-308267-S20300341142009020200000) ).
- When the air thermo sensor is activated, and the ignition switch, blower switch, and air conditioning switch are ON, the A/C compressor clutch relay is energized.
When operating the mode selection dial
- The air conditioning will work when the mode selection dial is set to the "Defroster" or "Defroster/foot" position, or the temperature control dial is set to the "MAXIMUM A/C" position. In other dial positions, when the air conditioning switch is turned on, the air conditioning will work.
A/C Compressor Clutch Relay ON Conditions
| Ignition switch (IG2) | ON | NOTE: A/C compressor clutch relay is de-energized when any one switch, sensor or control unit shown on the left turns off. NOTE: The components marked by () communicate with the ECM < M/T > or PCM < A/T >. If the air thermo sensor detects a temperature of 3°C (37.4°F), the A/C-ECU will turn off the A/C compressor clutch relay. | |
|---|---|---|---|
| Blower switch | ON | ||
| Air conditioning switch, mode selection dial defroster, defroster/foot position or temperature control MAX A/C | ON | ||
| Air thermo sensor | () | ||
| Pressure detected by A/C pressure sensor | 2.94 MPa (427 psi) or less (If the refrigerant pressure exceeds 2.94 MPa (427 psi), A/C compressor clutch relay is not ON condition until the refrigerant pressure has been measured up to 2.35 MPa (341 psi) a or less.) | ON | |
| 0.19 MPa (27 psi) or more (If the refrigerant pressure falls short of 0.19 MPa (27 psi), A/C compressor clutch relay is not ON condition until the refrigerant pressure has been measured up to 0.22 MPa (32 psi) or more.) | |||
| A/C compressor clutch relay driving transistor (within ECM < M/T > or PCM < A/T >) | ON | ||
| NOTE |
|---|
| A/C compressor clutch relay is de-energized when any one switch, sensor or control unit shown on the left turns off. |
| NOTE |
|---|
| The components marked by () communicate with the ECM < M/T > or PCM < A/T >. If the air thermo sensor detects a temperature of 3°C (37.4°F), the A/C-ECU will turn off the A/C compressor clutch relay. |
A/C COMPRESSOR CLUTCH RELAY ON CONDITIONS
HOW TO READ DATA LIST
Required Special Tools
- MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A
| CAUTION | To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958. |
Scheme 390
- Connect the scan tool MB991958 to the data link connector.
- Turn the ignition switch to the "ON" position.
- Select "Interactive Diagnosis" from the start-up screen.
- Select "System Select."
- Choose "AUTO A/C" from the "BODY" tab.
- Select "MITSUBISHI."
- Select "Data List."
- Choose an appropriate item and select the "OK" button.
FUNCTION
The Heater Air Intake Duct Sensor has characteristics that the resistance drops when the temperature rises, and it sends the information of the temperature inside the vehicle to the A/C-ECU to control the temperature.
DETECTION LOGIC
This code is set when the Heater Air Intake Duct Sensor circuit (power supply side) is shorted to ground.
PROBABLE CAUSES
- Malfunction of connector.
- Malfunction of the harness.
- Malfunction of the heater air intake duct sensor.
- Malfunction of the A/C-ECU.
The Heater Air Intake Duct Sensor has characteristics that the resistance drops when the temperature rises, and it sends the information of the temperature inside the vehicle to the A/C-ECU to control the temperature.
This code is set when the Heater Air Intake Duct Sensor circuit (power supply side and ground side) is open.
- Malfunction of connector.
- Malfunction of the harness.
- Malfunction of the heater air intake duct sensor.
- Malfunction of the A/C-ECU.
The ambient air temperature sensor has characteristics that the resistance drops when the temperature rises, and it sends the temperature information outside the vehicle to the A/C-ECU to control the temperature.
This code is set when the ambient air temperature sensor circuit (power supply side) is shorted to ground.
- Malfunction of connector.
- Malfunction of the harness.
- Malfunction of the ambient air temperature sensor.
- Malfunction of the A/C-ECU.
The ambient air temperature sensor has characteristics that the resistance drops when the temperature rises, and it sends the temperature information outside the vehicle to the A/C-ECU to control the temperature.
This code is set when the ambient air temperature sensor circuit (power supply side and ground side) is open.
- Malfunction of connector.
- Malfunction of the harness.
- Malfunction of the ambient air temperature sensor.
- Malfunction of the A/C-ECU.
The air thermo sensor sends the temperature information inside the heater unit to the A/C-ECU. The A/C-ECU controls the air mixing damper control motor and potentiometer to control the temperature of the air coming out of the vents.
This code is set when the air thermo sensor circuit (power supply side) is shorted to ground.
- Malfunction of connector.
- Malfunction of the harness.
- Malfunction of the air thermo sensor.
- Malfunction of the A/C-ECU.
The air thermo sensor sends the temperature information inside the heater unit to the A/C-ECU and controls the temperature of the air coming out of the vents.
This code is set when the air thermo sensor circuit is open (power supply side and ground side).
- Malfunction of connector.
- Malfunction of the harness.
- Malfunction of the air thermo sensor.
- Malfunction of the A/C-ECU.
Read the position of air mixing damper from the drive motor.
This code is set when the air mixing damper control motor and potentiometer do not send any signal to the A/C-ECU due to short to power supply of the air mixing damper control motor and potentiometer circuit.
- Malfunction of connector.
- Malfunction of the harness (air mixing damper control motor and potentiometer circuit is open/shorted to its power supply)
- Malfunction of the air mixing damper control motor and potentiometer.
- Malfunction of the A/C-ECU.
Read the position of air mixing damper from the drive motor.
This code is set when the air mixing damper control motor and potentiometer do not send any signal to the A/C-ECU due to an open circuit and short to ground of the air mixing damper control motor and potentiometer circuit.
- Malfunction of connector.
- Malfunction of the harness (Air mixing damper control motor and potentiometer circuit is open/shorted to ground)
- Malfunction of the Air mixing damper control motor and potentiometer.
- Malfunction of the A/C-ECU.
Takes in fresh air or inside air from the blower, and activates the damper on the side of the heater core to control the volume of the warm air that passes through the heater core and the cool air that does not pass through the heater core.
This code is set when the air mixing damper control motor and potentiometer cannot be rotated to the preset opening angle.
- Malfunction of connector.
- Malfunction of the harness (open circuit, damage or short to ground of air mixing damper control motor and potentiometer circuit, short to ground of pressure sensor circuit, and open circuit or damage of power supply (IG2) circuit)
- Malfunction of the air mixing damper control motor and potentiometer.
- Malfunction of the A/C-ECU.
- Malfunction of the junction block.
Read the position of mode selection damper from the drive motor.
This code is set when the mode selection damper control motor and potentiometer do not send any signal due to a short to power supply of the mode selection damper control motor and potentiometer circuit.
- Malfunction of connector.
- Malfunction of the harness (mode selection damper control motor and potentiometer circuit is open.)
- Malfunction of the mode selection damper control motor and potentiometer.
- Malfunction of the A/C-ECU.
Read the position of mode selection damper from the drive motor.
This code is set when the mode selection damper control motor and potentiometer do not send any signal to the A/C-ECU due to an open circuit and short to ground of the mode selection damper control motor and potentiometer circuit.
- Malfunction of connector.
- Malfunction of the harness (mode selection damper control motor and potentiometer circuit is open/damaged/shorted to ground)
- Malfunction of the mode selection damper control motor and potentiometer.
- Malfunction of the A/C-ECU.
Drive the mode selection damper control motor and control the outlet selection.
This code is set when the mode selection damper cannot be rotated to the preset opening angle.
- Malfunction of connector.
- Malfunction of the harness (mode selection damper control motor and potentiometer circuit is open, shorted to ground, or the resistance has increased)
- Malfunction of the mode selection damper control motor and potentiometer.
- Malfunction of the A/C pressure sensor.
- Malfunction of the A/C-ECU.
- Malfunction of connector.
- Malfunction of the harness (CAN line is open/shorted to ground)
- Malfunction of the A/C-ECU
- Malfunction of connector.
- Malfunction of the harness (CAN line is open/shorted to ground)
- Malfunction of the A/C-ECU.
- Malfunction of the ECM < M/T > or PCM < A/T >.
- Malfunction of connector.
- Malfunction of the harness.
- Malfunction of the A/C-ECU.
Changeover between inside air recirculation mode and fresh air mode
- Malfunction of connector.
- Malfunction of the harness (outside/inside air selection damper control motor circuit is open/shorted to ground)
- Malfunction of the outside/inside air selection damper control motor.
- Malfunction of the A/C-ECU.
Compressor that recovers the refrigerant, which evaporated in the evaporator and became a high-temperature and high-pressure gas, and turns it into liquid again.
- Insufficient refrigerant
- Malfunction of connector.
- Malfunction of the harness (A/C compressor circuit is open/shorted to ground)
- Malfunction of the A/C pressure sensor.
- Malfunction of the A/C compressor.
- Malfunction of the A/C compressor clutch relay.
- Malfunction of the A/C-ECU.
The air from the blower fan is cooled or warmed to control the temperature.
The air from the blower fan is cooled or warmed to control the temperature.
- Improper amount of refrigerant
- Malfunction of the A/C-ECU
The resistance of the photo sensor varies by the volume of the insulation intensity of sun light, and the sensor sends the information to the A/C-ECU to control the temperature.
- Malfunction of the harness (photo sensor circuit is open/shorted to ground)
- Malfunction of the photo sensor
- Malfunction of the A/C-ECU
- Malfunction of connector.
The condenser turns the high-temperature and high-pressure refrigerant into liquid by cooling it down with fresh air, and it is cooled down by the air from the condenser fan.
- Malfunction of connector.
- Malfunction of the harness (Pressure sensor circuit is open)
- Malfunction of the A/C pressure sensor.
- Malfunction of the condenser fan motor.
- Malfunction of the A/C-ECU.
DATA LIST REFERENCE TABLE
| MUT-III SCAN TOOL DISPLAY | ITEM NO. | INSPECTION ITEM | INSPECTION REQUIREMENT | NORMAL VALUE | |
|---|---|---|---|---|---|
| Air conditioning switch | 12 | Air conditioning switch | Ignition switch: ON | Air conditioning switch: ON | Scan tool indication: ON |
| Air conditioning switch: OFF | Scan tool indication: OFF | ||||
| Air thermo sensor | 20 | Air thermo sensor | Ignition switch: ON | The temperature measured behind the evaporator matches the displayed value on the scan tool while the engine is cold. | |
| Interior temperature sensor | 21 | Heater air intake duct sensor | Ignition switch: ON | Inside air temperature and temperature displayed on the scan tool are identical. | |
| Temperature setting | 23 | Preset temperature | Ignition switch: ON | The heater control preset temperature is the same as the scan tool display. | |
| Refrigerant leak | 29 | Refrigerant leak | Ignition switch: ON | The scan tool indication is normal | |
| Air outlet c/o potentiometer | 55 | Mode selection damper control motor potentiometer | Ignition switch: ON | Damper position | Opening degree (%) |
| FACE | Approx. 100 | ||||
| FOOT | Approx. 75 | ||||
| FOOT/DEF. | Approx. 50 | ||||
| DEF. | Approx. 0 | ||||
| Air outlet c/o potentiometer. (target) | 56 | Target value for mode selection damper control motor potentiometer | Ignition switch: ON | Damper position | Opening degree (%) |
| FACE | Approx. 100 | ||||
| FOOT | Approx. 75 | ||||
| FOOT/DEF. | Approx. 50 | ||||
| DEF. | Approx. 0 | ||||
| Low pressure judgment | 57 | Refrigerant pressure | Ignition switch: ON | The scan tool indication is normal | |
| Ambient air temperature sensor | 58 | Ambient air temperature sensor | Ignition switch: ON | Outside air temperature and temperature displayed on the scan tool are identical. | |
| Rear defogger switch | 60 | Rear window defogger switch | Ignition switch: ON | Rear window defogger switch: ON | Scan tool indication: ON |
| Rear window defogger switch: OFF | Scan tool indication: OFF | ||||
| Pressure sensor | 61 | A/C pressure sensor | Ignition switch: ON | Measured refrigerant pressure is nearly equal to the value shown on the scan tool. | |
| Water temperature sensor | 62 | Engine coolant temperature sensor (Data received by CAN Communication) | Ignition switch: ON | Engine coolant temperature and temperature displayed on the scan tool are identical. | |
| Air mix potentiometer | 63 | Air mixing damper control motor potentiometer | Ignition switch: ON | Damper position | Opening degree (%) |
| MAX. HOT | Approx. 100 | ||||
| MAX. COOL | Approx. 0 | ||||
| Air mix potentiometer (Target) | 64 | Target value for air mixing damper control motor potentiometer | Ignition switch: ON | Damper position | Opening degree (%) |
| MAX. HOT | Approx. 100 | ||||
| MAX. COOL | Approx. 0 | ||||
| In/out air c/o damper motor | 65 | Outside/inside air selection damper control motor | Ignition switch: ON | Damper set position | Damper position |
| Fresh air position | FRESH | ||||
| Air recirculation position | RECIRC | ||||
| Photo sensor | 67 | Photo sensor | Ignition switch: ON | Amount of light is proportional to voltage displayed on the scan tool. | |
| Front blower fan | 68 | Blower motor | Ignition switch: ON | Display the blower motor speed. | |
| Front blower fan (Target) | 68 | Blower motor (Target) | Ignition switch: ON | Display the target value of blower motor speed. | |
DATA LIST REFERENCE
HEATER AIR INTAKE DUCT SENSOR CHECK
When the resistance between the sensor terminals is measured under two or more temperature conditions, the resistance should approximately satisfy the illustrated values.
Note. The temperature conditions when checking should not exceed the range shown in the diagram.
Scheme 391
Scheme 392
- Connect scan tool MB991958, and check the data list of the photo sensor. Refer to «DATA LIST REFERENCE TABLE»(ref-308267-S25037714842009020200000) .
- Check that the displayed value changes when you cover the photo sensor with your hands or a shop towel.