Air Conditioning System (For Automatic A/c) (Diagnostic Codes & Circuit Tests): Overview Toyota Corolla X рестайлинг

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1. ACTUATOR CHECK Start the engine and warm it up. Perform the indicator check. Refer to «DIAGNOSIS SYSTEM»(ref-426063-S16986265902011101200000). Push the "R/F" switch to perform the actuator check. HINT: Be sure to perform the actuator check after starting the engine. As the actuator check is repeated from steps 1 to 10 at 1 second intervals, check the temperature and air flow visually and by hand. HINT: The display blinks at 1 second intervals in the step operation. Push the "OFF" switch to finish panel diagnosis. Push the "AUTO" switch to enter the sensor check mode. Step No. Display Code Condition Blower Level Air Mix Damper Airflow Vent Air Inlet Damper Compressor 1 0 0 0% open FACE FRESH OFF 2 1 1 0% open FACE FRESH OFF 3 2 17 0% open FACE RECIRCULATION/FRESH ON 4 3 17 0% open FACE RECIRCULATION ON 5 4 17 50% open B/L RECIRCULATION ON 6 5 17 50% open B/L RECIRCULATION ON 7 6 17 50% open FOOT FRESH ON 8 7 17 100% open FOOT-0 FRESH ON 9 8 17 100% open F/D FRESH ON 10 9 31 100% open DEF FRESH ON If the steps are difficult to read because they change automatically, push the "DEF" switch to display the steps one at a time so that they can be read easily. The items are displayed step by step each time the "DEF" switch is pushed. HINT: Push the "OFF" switch to finish panel diagnosis. Push the "R/F" switch to enter the sensor check mode.

DESCRIPTION

This sensor detects the cabin temperature that is used as the basis for temperature control and sends a signal to the A/C amplifier.

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Scheme 285

1. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the ignition switch to ON. Turn the Techstream on. Enter the following menus: Body / Air Conditioner / Data List. Check the value(s) by referring to the table below. AIR CONDITIONER Tester Display Measurement Item/Range Normal Condition Diagnostic Note Room Temperature Sensor (Room Temp) Room temperature sensor / Min.: -6.5°C (20.3°F), Max.: 57.25°C (135.05°F) Actual cabin temperature displayed - OK The display is as specified in the "Normal Condition" column. Result Result Proceed to NG A OK (When troubleshooting according to Problem Symptoms Table) B OK (When troubleshooting according to DTC) C C --> See step 5 B --> See step 4 A: Go to next step
2. INSPECT ROOM TEMPERATURE SENSOR Remove the room temperature sensor. Disconnect the connector from the room temperature sensor. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition E25-1 - E25-2 10°C (50°F) 3.00 to 3.73 kohms E25-1 - E25-2 15°C (59°F) 2.45 to 2.88 kohms E25-1 - E25-2 20°C (68°F) 1.95 to 2.30 kohms E25-1 - E25-2 25°C (77°F) 1.60 to 1.80 kohms E25-1 - E25-2 30°C (86°F) 1.28 to 1.47 kohms E25-1 - E25-2 35°C (95°F) 1.00 to 1.22 kohms E25-1 - E25-2 40°C (104°F) 0.80 to 1.00 kohms E25-1 - E25-2 45°C (113°F) 0.65 to 0.85 kohms E25-1 - E25-2 50°C (122°F) 0.50 to 0.70 kohms E25-1 - E25-2 55°C (131°F) 0.44 to 0.60 kohms E25-1 - E25-2 60°C (140°F) 0.36 to 0.50 kohms NOTE: Hold the sensor only by its connector. Touching the sensor may change the resistance value. When measuring, the sensor temperature must be the same as the ambient temperature. HINT: As the temperature increases, the resistance decreases (see the graph. (Scheme 285)). TEXT IN ILLUSTRATION *a Component without harness connected (Room Temperature Sensor) *b Sensing Portion *c Resistance (kohms) *d Allowable Range *e Temperature (°C (°F)) NG --> See step 6 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (ROOM TEMPERATURE SENSOR - AIR CONDITIONING AMPLIFIER) Disconnect the connector from the A/C amplifier. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition E30-29 (TR) - E25-1 Always Below 1 ohms E30-34 (SG-1) - E25-2 Always Below 1 ohms E30-29 (TR) - Body ground Always 10 kohms or higher E30-34 (SG-1) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 5
4. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-426063-S09610016122011101200000)
5. REPLACE AIR CONDITIONING AMPLIFIER. Refer to «REMOVAL»(ref-426074-S42757149022011101200000)
6. REPLACE ROOM TEMPERATURE SENSOR. Refer to «REMOVAL»(ref-426074-S08084820182011101200000)

This sensor detects the temperature outside the cabin and sends the appropriate signals to the A/C amplifier via the CAN communication system.

Scheme 286

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Scheme 288

1. CHECK CAN COMMUNICATION SYSTEM (COMBINATION METER - A/C AMPLIFIER) Use the Techstream. Check that the CAN communication system functions normally between the combination meter and the A/C amplifier. Result Result Proceed to CAN DTC is not output A CAN DTC is output B B --> See step 6 A: Go to next step
2. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the ignition switch to ON. Turn the Techstream on. Enter the following menus: Body / Air Conditioner / Data List. Check the value(s) by referring to the table below. AIR CONDITIONER Tester Display Measurement Item/Range Normal Condition Diagnostic Note Ambient Temp Sensor (Ambi Temp Sens) Ambient temperature sensor / Min: -23.3°C (-9.94°F), Max: 65.95°C (150.71°F) Actual ambient temperature displayed Open in circuit: -23.3°C (-9.94°F) Short in circuit: 65.95°C (150.71°F) OK The display is as specified in the "Normal Condition" column. Result Result Proceed to NG A OK (When troubleshooting according to Problem Symptoms Table) B OK (When troubleshooting according to DTC) C C --> See step 8 B --> See step 7 A: Go to next step
3. CHECK HARNESS AND CONNECTOR (AMBIENT TEMPERATURE SENSOR CIRCUIT) Disconnect the connector from the combination meter. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition E46-9 (TX1+) - E46-23 (TEMP) Outside temperature: 25°C (77°F) 1.60 to 1.80 kohms E46-9 (TX1+) - E46-23 (TEMP) Outside temperature: 40°C (104°F) 0.80 to 1.00 kohms HINT: As the temperature increases, the resistance decreases. TEXT IN ILLUSTRATION *a Front view of wire harness connector (to Combination Meter) NG --> See step 5 OK: Go to next step
4. REPLACE COMBINATION METER Replace the combination meter. Refer to «REMOVAL»(ref-426052-S32990996932011101200000). HINT: Since the combination meter cannot be inspected while it is removed from the vehicle, replace the combination meter with a known good one and check that the condition returns to normal. Check for DTCs. Result Result Proceed to DTC B1412 is not output A DTC B1412 is output B B --> See step 8 A --> END
5. INSPECT AMBIENT TEMPERATURE SENSOR Remove the ambient temperature sensor. Disconnect the connector from the ambient temperature sensor. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A23-1 - A23-2 10°C (50°F) 3.00 to 3.73 kohms A23-1 - A23-2 15°C (59°F) 2.45 to 2.88 kohms A23-1 - A23-2 20°C (68°F) 1.95 to 2.30 kohms A23-1 - A23-2 25°C (77°F) 1.60 to 1.80 kohms A23-1 - A23-2 30°C (86°F) 1.28 to 1.47 kohms A23-1 - A23-2 35°C (95°F) 1.00 to 1.22 kohms A23-1 - A23-2 40°C (104°F) 0.80 to 1.00 kohms A23-1 - A23-2 45°C (113°F) 0.65 to 0.85 kohms A23-1 - A23-2 50°C (122°F) 0.50 to 0.70 kohms A23-1 - A23-2 55°C (131°F) 0.44 to 0.60 kohms A23-1 - A23-2 60°C (140°F) 0.36 to 0.50 kohms NOTE: Hold the sensor only by its connector. Touching the sensor may change the resistance value. When measuring, the sensor temperature must be the same as the ambient temperature. HINT: As the temperature increases, the resistance decreases (see the graph. (Scheme 288)). TEXT IN ILLUSTRATION *a Component without harness connected (Ambient Temperature Sensor) *b Sensing Portion *c Resistance (kohms) *d Allowable Range *e Temperature (°C (°F)) NG --> See step 9 OK --> REPAIR OR REPLACE HARNESS OR CONNECTOR (COMBINATION METER - AMBIENT TEMPERATURE SENSOR)
6. GO TO CAN COMMUNICATION SYSTEM. Refer to «HOW TO PROCEED WITH TROUBLESHOOTING»(ref-426086-S42356372512011101200000)
7. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-426063-S09610016122011101200000)
8. REPLACE AIR CONDITIONING AMPLIFIER. Refer to «REMOVAL»(ref-426074-S42757149022011101200000)
9. REPLACE AMBIENT TEMPERATURE SENSOR. Refer to «REMOVAL»(ref-426074-S31210559182011101200000)

The evaporator temperature sensor (A/C thermistor) is installed on the evaporator in the air conditioning unit. It detects the temperature of the cooled air that has passed through the evaporator and its signal is used to control the air conditioning. It sends a signal to the A/C amplifier. The resistance of the evaporator temperature sensor (A/C thermistor) changes in accordance with the temperature of the cooled air that has passed through the evaporator. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The A/C amplifier applies voltage (5 V) to the evaporator temperature sensor (A/C thermistor) and reads voltage changes as the resistance of the evaporator temperature sensor (A/C thermistor) changes. This sensor is used to prevent the evaporator from freezing.

Scheme 289

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Scheme 291

1. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the ignition switch to ON. Turn the Techstream on. Enter the following menus: Body / Air Conditioner / Data List. Check the value(s) by referring to the table below. AIR CONDITIONER Tester Display Measurement Item/Range Normal Condition Diagnostic Note Evaporator Fin Thermistor (Evap Fin Temp) Evaporator fin temperature / Min.: -29.7°C (-21.46°F), Max.: 59.55°C (139.19°F) Actual evaporator temperature displayed Open in circuit: -29.7°C (-21.46°F) Short in circuit: 59.55°C (139.19°F) OK The display is as specified in the "Normal Condition" column. Result Result Proceed to NG A OK (When troubleshooting according to Problem Symptoms Table) B OK (When troubleshooting according to DTC) C C --> See step 4 B --> See step 5 A: Go to next step
2. INSPECT EVAPORATOR TEMPERATURE SENSOR Remove the evaporator temperature sensor. Disconnect the connector from the evaporator temperature sensor. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition x2-1 - x2-2 -10°C (14°F) 7.30 to 9.10 kohms x2-1 - x2-2 -5°C (23°F) 5.65 to 6.95 kohms x2-1 - x2-2 0°C (32°F) 4.40 to 5.35 kohms x2-1 - x2-2 5°C (41°F) 3.40 to 4.15 kohms x2-1 - x2-2 10°C (50°F) 2.70 to 3.25 kohms x2-1 - x2-2 15°C (59°F) 2.14 to 2.58 kohms x2-1 - x2-2 20°C (68°F) 1.71 to 2.05 kohms x2-1 - x2-2 25°C (77°F) 1.38 to 1.64 kohms x2-1 - x2-2 30°C (86°F) 1.11 to 1.32 kohms NOTE: Hold the sensor only by its connector. Touching the sensor may change the resistance value. When measuring, the sensor temperature must be the same as the ambient temperature. HINT: As the temperature increases, the resistance decreases (see the graph. (Scheme 290)). TEXT IN ILLUSTRATION *a Component without harness connected (Evaporator Temperature Sensor) *b Sensing Portion *c Resistance (kohms) *d Allowable Range *e Temperature (°C (°F)) NG --> See step 6 OK: Go to next step
3. INSPECT AIR CONDITIONING HARNESS Remove the air conditioning harness. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition X1-6 (TEA) - x2-2 Always Below 1 ohms X1-5 (SGA) - x2-1 Always Below 1 ohms X1-6 (TEA) - Body ground Always 10 kohms or higher X1-5 (SGA) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *a Front view of wire harness connector (to Evaporator Temperature Sensor) *b Front view of wire harness connector (to A/C Amplifier) NG --> See step 7 OK --> See step 4
4. REPLACE AIR CONDITIONING AMPLIFIER. Refer to «REMOVAL»(ref-426074-S42757149022011101200000)
5. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-426063-S09610016122011101200000)
6. REPLACE EVAPORATOR TEMPERATURE SENSOR. Refer to «REMOVAL»(ref-426074-S37986888622011101200000)
7. REPLACE AIR CONDITIONING HARNESS. Refer to «DISASSEMBLY»(ref-426074-S09310264522011101200000)

Scheme 292

The solar sensor, which is installed on the upper side of the instrument panel, detects sunlight and controls the air conditioning in AUTO mode. The output voltage from the solar sensor varies according to the amount of sunlight. When the sunlight increases, the output voltage increases. As the sunlight decreases, the output voltage decreases. The A/C amplifier detects voltage output from the solar sensor.

Scheme 293

This DTC is output when refrigerant pressure on the high pressure side is extremely low (0.19 MPa (2.0 kgf/cm 2 , 28 psi) or less) or extremely high (3.14 MPa (32.0 kgf/cm 2 , 455 psi) or more). The A/C pressure sensor, which is installed on the high pressure side pipe to detect refrigerant pressure, outputs a refrigerant pressure signal to the A/C amplifier. The A/C amplifier converts this signal to a pressure value according to the sensor characteristics to control the compressor.

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1. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) Disconnect the connector from the A/C pressure sensor. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition A16-3 (+) - Body ground Ignition switch ON 4.75 to 5.25 V TEXT IN ILLUSTRATION *a Front view of wire harness connector (to A/C Pressure Sensor) NG --> See step 11 OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A16-1 (-) - Body ground Always Below 1 ohms TEXT IN ILLUSTRATION *a Front view of wire harness connector (to A/C Pressure Sensor) NG --> See step 12 OK: Go to next step
3. INSPECT A/C PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT) Reconnect the connector to the A/C pressure sensor. Remove the A/C amplifier with the connectors still connected. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition E30-9 (PRE) - Body ground Ignition switch ON (A/C: OFF) 0.7 to 4.8 V HINT: If the measured voltage is not within the normal range, there may be a malfunction in the A/C amplifier, A/C pressure sensor, or wire harness. It is also possible that the amount of refrigerant may not be appropriate. TEXT IN ILLUSTRATION *a Component with harness connected (A/C Amplifier) NG --> See step 13 OK: Go to next step
4. INSPECT A/C PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT) Measure the voltage when the following conditions are satisfied. Item Condition Vehicle Doors Fully open Temperature Setting MAX COLD Blower Speed HI A/C Switch ON R/F Switch RECIRCULATION Interior Temperature 25 to 35°C (77 to 95°F) Engine Speed 2000 RPM NOTE: If refrigerant pressure on the high pressure side becomes extremely high during the inspection (if the voltage exceeds 4.8 V), the fail-safe function stops compressor operation. Therefore, measure the voltage before the fail-safe function operates. It is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) because the problem symptom may recur after a while. HINT: When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to the operation of the ambient temperature and the evaporator temperature sensor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition E30-9 (PRE) - Body ground Ignition switch ON (A/C: ON) 0.7 to 4.8 V Result Result Proceed to NG A OK (When troubleshooting according to Problem Symptoms Table) B OK (When troubleshooting according to DTC) C TEXT IN ILLUSTRATION *a Component with harness connected (A/C Amplifier) C --> See step 21 B --> See step 19 A: Go to next step
5. INSPECT COOLING FAN SYSTEM Check that the cooling fan operates normally. HINT: Refer to Cooling Fan Circuit for 2AZ-FE. Refer to «Cooling Fan Circuit»(ref-426085-S28836061272011101200000) for 2ZR-FE. NG --> REPAIR COOLING FAN SYSTEM OK: Go to next step
6. CHARGE REFRIGERANT Use a refrigerant recovery unit to recover refrigerant. Evacuate the A/C system. Add an appropriate amount of refrigerant. Refer to «REPLACEMENT - Step 2»(ref-426074-S42468343772011101200000). HINT: If refrigerant is added and the system has not been properly evacuated (insufficient vacuum time), moisture in the air remaining in the system will freeze in the expansion valve, blocking the flow on the high pressure side. Therefore, in order to confirm the problem, recover the refrigerant and properly evacuate the system. Add an appropriate amount of refrigerant, and check for DTCs. NEXT: Go to next step
7. RECHECK DTC Recheck for DTCs when the following conditions are satisfied. Item Condition Vehicle Doors Fully open Temperature Setting MAX COLD Blower Speed HI A/C Switch ON R/F Switch RECIRCULATION Interior Temperature 25 to 35°C (77 to 95°F) Engine Speed 2000 RPM NOTE: If refrigerant pressure on the high pressure side becomes high, the DTC will be set. Therefore, it is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) because the DTC may be set after the A/C operates for a while. HINT: When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to operation of the ambient temperature sensor and the evaporator temperature sensor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment. If refrigerant is added and the system has not been properly evacuated (insufficient vacuum time), moisture in the air remaining in the system will freeze in the expansion valve, blocking the flow on the high pressure side. Therefore, in order to confirm the problem, recover the refrigerant and properly evacuate the system. Add an appropriate amount of refrigerant, and check for DTCs. If the DTC is not output after this work, it indicates that the cooler dryer in the condenser is not able to absorb moisture in the refrigerant cycle. In this case, to complete the repair, it is necessary to replace the cooler dryer. Result Result Proceed to DTC B1423 is not output A DTC B1423 is output B B --> See step 8 A --> See step 23
8. REPLACE EXPANSION VALVE Replace the expansion valve with a new one. Refer to «DISASSEMBLY»(ref-426074-S09310264522011101200000). HINT: Replace the expansion valve with a new one because the expansion valve is either stuck or clogged. NEXT: Go to next step
9. CHARGE REFRIGERANT Add an appropriate amount of refrigerant. Refer to «REPLACEMENT - Step 2»(ref-426074-S42468343772011101200000). NEXT: Go to next step
10. RECHECK DTC Recheck for DTCs when the following conditions are satisfied. Item Condition Vehicle Doors Fully open Temperature Setting MAX COLD Blower Speed HI A/C Switch ON R/F Switch RECIRCULATION Interior Temperature 25 to 35°C (77 to 95°F) Engine Speed 2000 RPM NOTE: If refrigerant pressure on the high pressure side becomes high, the DTC will be set. Therefore, it is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) because the DTC may be set after the A/C operates for a while. HINT: When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to the operation of the ambient temperature sensor and the evaporator temperature sensor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment. If refrigerant pressure is not normal after replacing the expansion valve with a new one, the condenser or pipes may be clogged due to dirt, dust or other contaminants. In this case, clean or replace the condenser or pipes. Result Result Proceed to DTC B1423 is not output A DTC B1423 is output B B --> See step 24 A --> END
11. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - A/C PRESSURE SENSOR) Disconnect the connector from the A/C amplifier. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A16-3 (+) - E30-10 (S5-3) Always Below 1 ohms E30-10 (S5-3) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 21
12. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - A/C PRESSURE SENSOR) Disconnect the connector from the A/C amplifier. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A16-1 (-) - E30-13 (SG-2) Always Below 1 ohms E30-13 (SG-2) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 21
13. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - A/C PRESSURE SENSOR) Disconnect the connector from the A/C amplifier. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A16-2 (PR) - E30-9 (PRE) Always Below 1 ohms E30-9 (PRE) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
14. INSPECT FOR A/C SYSTEM LEAK Install the manifold gauge set. Recover the refrigerant from the A/C system using a refrigerant recovery unit. Evacuate the A/C system and check that vacuum can be maintained. OK Vacuum can be maintained in the A/C system. HINT: If vacuum cannot be maintained in the A/C system, there may be a refrigerant leak. In this case, it is necessary to repair or replace the leaking part of the A/C system. NG --> See step 18 OK: Go to next step
15. CHARGE REFRIGERANT Add an appropriate amount of refrigerant. Refer to «REPLACEMENT - Step 2»(ref-426074-S42468343772011101200000). NEXT: Go to next step
16. RECHECK DTC Recheck for DTCs when the following conditions are satisfied. Item Condition Vehicle Doors Fully open Temperature Setting MAX COLD Blower Speed HI A/C Switch ON R/F Switch RECIRCULATION Interior Temperature 25 to 35°C (77 to 95°F) Engine Speed 2000 RPM NOTE: If refrigerant pressure on the high pressure side becomes high, the DTC will be set. Therefore, it is necessary to measure the voltage for a certain amount of time (approximately 10 minutes) because the DTC may be set after the A/C operates for a while. HINT: When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to the operation of the ambient temperature sensor and the evaporator temperature sensor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment. Result Result Proceed to DTC B1423 is not output A DTC B1423 is output B NOTE: If the DTC was set due to an insufficient or excessive amount of refrigerant, the problem may have been solved after performing the previous step. However, the root cause of insufficient refrigerant may be refrigerant leaks. The root cause of excessive refrigerant may be adding refrigerant when the level was insufficient. Therefore, identify and repair the area where refrigerant leaks from as necessary. B --> See step 17 A --> END
17. INSPECT A/C PRESSURE SENSOR Install the manifold gauge set. Disconnect the connector from the A/C pressure sensor. Connect the three 1.5 V dry cell batteries' positive (+) lead to terminal 3, and the negative (-) lead to terminal 1. Connect the voltmeter's positive (+) lead to terminal 2, and the negative (-) lead to terminal 1. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition A16-2 (PR) - A16-1 (-) Refrigerant pressure: 0.39 to 3.187 MPa (57 to 463 psi) 1.0 to 4.8 V TEXT IN ILLUSTRATION *a Component without harness connected (A/C Pressure Sensor) *b Voltage (V) *c Refrigerant Pressure (MPa (psi)) NG --> See step 20 OK --> See step 21
18. REPAIR A/C SYSTEM LEAK Identify the area where refrigerant leaks from. Refer to «REPLACEMENT - Step 4»(ref-426074-S42468343772011101200000). Repair the identified area of the A/C system. Evacuate the A/C system. NEXT --> See step 22
19. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-426063-S09610016122011101200000)
20. REPLACE A/C PRESSURE SENSOR. Refer to «REMOVAL»(ref-426074-S29168219202011101200000)
21. REPLACE AIR CONDITIONING AMPLIFIER. Refer to «REMOVAL»(ref-426074-S42757149022011101200000)
22. CHARGE REFRIGERANT. Refer to «REPLACEMENT - Step 2»(ref-426074-S42468343772011101200000)
23. REPLACE COOLER DRYER. Refer to «DISASSEMBLY»(ref-426074-S09484468392011101200000)
24. REPLACE CONDENSER. Refer to «REMOVAL»(ref-426074-S10093443852011101200000)

The air mix damper servo sends pulse signals to inform the air conditioning amplifier of the damper position. The air conditioning amplifier activates the motor (normal, reverse) based on the signals to move the air mix damper (passenger seat) to any position, which adjusts the amount of air passing the heater core after passing the evaporator to control the blowing temperature. The A/C amplifier communicates with the servo through a communication/driver IC and wiring assembly called the air conditioning harness.

HINT

Confirm that no mechanical problem is present because this DTC can be output when either a damper link or the damper is mechanically locked.

Scheme 300

The damper servo (air inlet control) sends pulse signals to inform the air conditioning amplifier of the damper position. The air conditioning amplifier activates the motor (normal, reverse) based on the signals to move the air inlet damper to any position, which controls the intake air settings (FRESH, FRESH/RECIRCULATION, and RECIRCULATION). The A/C amplifier communicates with the servo through a communication/driver IC and wiring assembly called the air conditioning harness.

HINT

Confirm that no mechanical problem is present because this DTC can be output when either a damper link or the damper is mechanically locked.

Scheme 301

The mode damper servo sends pulse signals to inform the air conditioning amplifier of the damper position. The air conditioning amplifier activates the motor (normal, reverse) based on the signals to move the air outlet damper to any position, which controls the air outlet switching. The A/C amplifier communicates with the servo through a communication/driver IC and wiring assembly called the air conditioning harness.

HINT

Confirm that no mechanical problem is present because this DTC can be output when either a damper link or the damper is mechanically locked.

Scheme 302

Through this circuit, the compressor assembly with pulley receives a refrigerant compression demand signal from the air conditioning amplifier.

Based on this signal, the compressor assembly with pulley changes the amount of compressor output.

Scheme 303

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Scheme 305

1. INSPECT COMPRESSOR ASSEMBLY WITH PULLEY Disconnect the compressor assembly with pulley (compressor solenoid) connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition B7-2 (SOL+) - B7-1 (SOL-)*1 20°C (68°F) 10 to 11 ohms B94-2 (SOL+) - B94-1 (SOL-)*2 20°C (68°F) 10 to 11 ohms *1: for TMC Made *2: except TMC Made TEXT IN ILLUSTRATION *A for TMC Made *B except TMC Made *a Component without harness connected (Compressor Assembly with Pulley (Compressor Solenoid)) Result Result Proceed to OK A NG (for 2AZ-FE) B NG (for 2ZR-FE) C C --> See step 7 B --> See step 6 A: Go to next step
2. CHECK HARNESS AND CONNECTOR (COMPRESSOR ASSEMBLY WITH PULLEY - BODY GROUND) Disconnect the compressor assembly with pulley (compressor solenoid) connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition B7-1 (SOL-) - Body ground*1 Always Below 1 ohms B94-1 (SOL-) - Body ground*2 Always Below 1 ohms *1: for TMC Made *2: except TMC Made TEXT IN ILLUSTRATION *A for TMC Made *B except TMC Made *a Front view of wire harness connector (to Compressor Assembly with Pulley (Compressor Solenoid)) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (COMPRESSOR ASSEMBLY WITH PULLEY - A/C AMPLIFIER) Disconnect the compressor assembly with pulley (compressor solenoid) connector. Disconnect the A/C amplifier connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition E30-2 (SOL+) - B7-2 (SOL+)*1 Always Below 1 ohms E30-2 (SOL+) - B94-2 (SOL+)*2 Always Below 1 ohms E30-2 (SOL+) - Body ground Always 10 kohms or higher *1: for TMC Made *2: except TMC Made Result Result Proceed to NG A OK (When troubleshooting according to Problem Symptoms Table) B OK (When troubleshooting according to DTC) C C --> See step 5 B --> See step 4 A --> REPAIR OR REPLACE HARNESS OR CONNECTOR
4. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-426063-S09610016122011101200000)
5. REPLACE AIR CONDITIONING AMPLIFIER. Refer to «REMOVAL»(ref-426074-S42757149022011101200000)
6. REPLACE COMPRESSOR ASSEMBLY WITH PULLEY (for 2AZ-FE). Refer to «REMOVAL»(ref-426074-S32589387912011101200000)
7. REPLACE COMPRESSOR ASSEMBLY WITH PULLEY (for 2ZR-FE). Refer to «REMOVAL»(ref-426074-S20165499472011101200000)

The A/C flow sensor, which is mounted on the compressor assembly with pulley, is used to detect the amount of refrigerant flow. The A/C flow sensor converts the amount of refrigerant flow that is detected to a voltage value to send it to the A/C amplifier. The voltage value sent from the A/C flow sensor changes depending on the amount of refrigerant flow. As the amount of refrigerant flow becomes larger, the voltage becomes lower. As the amount of refrigerant flow becomes smaller, the voltage becomes higher. The A/C amplifier supplies 5 V to the A/C flow sensor and monitors change in the voltage value sent from the A/C flow sensor. The A/C amplifier then sends a signal to the ECM via CAN communication to allow the ECM to control the engine speed while the air conditioning is on.

Scheme 306

The air conditioning harness connects the air conditioning amplifier and each servo motor. The air conditioning amplifier supplies power and sends operation instructions to each servo motor through the air conditioning harness. Each servo motor sends the damper position information to the air conditioning amplifier. The A/C amplifier communicates with the servo through a communication/driver IC and wiring assembly called the air conditioning harness.

Scheme 307

Scheme 308

Scheme 309

1. CHECK HARNESS AND CONNECTOR Remove the A/C amplifier. Disconnect the connector from the A/C amplifier. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition E30-14 (GND) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
2. INSPECT AIR CONDITIONING AMPLIFIER Reconnect the connector to the A/C amplifier. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition X1-2 (BUS G) - E30-14 (GND) Always Below 1 ohms TEXT IN ILLUSTRATION *a Component with harness connected (A/C Amplifier) NG --> See step 5 OK: Go to next step
3. INSPECT AIR CONDITIONING AMPLIFIER Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition X1-4 (B BUS) - Body ground Ignition switch off Below 1 V X1-4 (B BUS) - Body ground Ignition switch ON 11 to 14 V TEXT IN ILLUSTRATION *a Component with harness connected (A/C Amplifier) NG --> See step 5 OK: Go to next step
4. REPLACE AIR CONDITIONING HARNESS Replace the air conditioning harness. Refer to «DISASSEMBLY»(ref-426074-S09310264522011101200000). HINT: Since the air conditioning harness cannot be inspected while it is removed from the vehicle, replace the air conditioning harness with a known good one and check that the condition returns to normal. Check for DTCs. Result Result Proceed to DTC B1497/97 is not output A DTC B1497/97 is output B B --> See step 5 A --> END
5. REPLACE AIR CONDITIONING AMPLIFIER. Refer to «REMOVAL»(ref-426074-S42757149022011101200000)

The blower motor is operated by signals from the A/C amplifier. Blower motor speed signals are transmitted in accordance with changes in the duty ratio.

Scheme 310

Battery voltage is supplied to the A/C control assembly through the ECU-IG No. 2 fuse.

Scheme 311

The PTC heater is installed in the heater unit and operates when the coolant temperature is low and normal heater operation is insufficient.

The A/C amplifier switches the circuit in the PTC relay and operates the PTC heater when the operating conditions (the coolant temperature is below 65°C (149°F), setting temperature is MAX. HOT, ambient temperature is below 10°C (50°F) and blower switch is not OFF) are met.

The PTC heater controls the number of the heater elements to be heated based on the electrical load and the amount of voltage generated. Therefore, when inspecting the PTC heater, be sure to turn off other electrical devices.

Scheme 312

The A/C amplifier receives headlight operational signals to determine the electrical load. The electrical load signals are used for controlling the number of the PTC heater elements to be heated.

Scheme 313

Scheme 314

1. INSPECT HEADLIGHT ASSEMBLY Check if the headlights come on when the light control switch is turned to the HEAD position. OK The headlights come on. NG --> See step 4 OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (HEADLIGHT SIGNAL) Disconnect the connector from the A/C amplifier. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition E30-27 (HLS) - Body ground Light control switch: OFF 11 to 14 V E30-27 (HLS) - Body ground Light control switch: HEAD Below 1 V TEXT IN ILLUSTRATION *a Front view of wire harness connector (to A/C Amplifier) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 3
3. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-426063-S09610016122011101200000)
4. GO TO LIGHTING SYSTEM. Refer to «Headlight Relay Circuit»(ref-426115-S17908980842011101200000)

When the engine is started, the generator rotates and a pulsed voltage signal is generated. This signal is used by the A/C amplifier. The generated voltage signals sent from the generator are used for controlling the number of the heater elements to be heated.

Scheme 315

The main power source is supplied to the A/C amplifier when the ignition switch is ON.

The power source is used for operating the A/C amplifier and servo motor, etc.

Scheme 316

The back-up power source circuit for the A/C amplifier is shown below. Power is supplied even when the ignition switch is off and is used for diagnostic trouble code memory, etc.

Scheme 317

Switch operational signals are exchanged between terminal LIN1 of the A/C control assembly and terminal LIN1 of the A/C amplifier.

Scheme 318

See also:
• INSPECTION