Air Conditioning System (Diagnostic Codes & Circuit Tests): Overview Scion xB II рестайлинг

DESCRIPTION

The ambient temperature sensor is installed in front of the condenser. This sensor detects the temperature outside the cabin and sends the appropriate signals to the A/C amplifier via the CAN communication system.

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1. CHECK CAN COMMUNICATION SYSTEM Use the Techstream to check if the CAN communication system DTC. Result Result Proceed to B1499 is not output A B1499 is output B B --> See step 12 A: Go to next step
2. READ VALUE USING TECHSTREAM (AMBIENT TEMPERATURE SENSOR) Use the Data List to check if the ambient temperature sensor is functioning properly. AIR CONDITIONER: Tester Display Measurement Item / Display (Range) Normal Condition Diagnostic Note Ambient Temp Sensor Ambient temperature sensor / Min: -23.3°C (-9.94°F), Max: 65.95°C (150.71°F) Actual ambient temperature is 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 (Checking from the PROBLEM SYMPTOMS TABLE) B OK (Checking from the DTC) C B --> See step 10 C --> See step 13 A: Go to next step
3. INSPECT COMBINATION METER Disconnect the C37 combination meter connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition C37-23 (TX1+) - C37-18 (TEMP) 25°C (77°F) 1.60 to 1.80 kohms C37-23 (TX1+) - C37-18 (TEMP) 40°C (104°F) 0.80 to 1.00 kohms Reconnect the combination meter connector. NG --> See step 6 OK: Go to next step
4. REPLACE COMBINATION METER Replace the combination meter. Refer to «REMOVAL»(ref-511398-S03938641392012102600000). HINT: Since the combination meter cannot be inspected while it is removed from the vehicle, replace the combination meter with a normal one and check that the condition returns to normal. NEXT: Go to next step
5. CHECK FOR DTC Clear the DTC. Refer to «DTC CHECK / CLEAR»(ref-511402-S00684680972012102600000). Check for DTCs. Refer to «DTC CHECK / CLEAR»(ref-511402-S00684680972012102600000). Result Result Proceed to DTC B1412 is not output A DTC B1412 is output B B --> See step 13 A --> END
6. INSPECT AMBIENT TEMPERATURE SENSOR Remove the ambient temperature sensor. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition A15-1 - A15-2 10°C (50°F) 3.00 to 3.73 kohms A15-1 - A15-2 15°C (59°F) 2.45 to 2.88 kohms A15-1 - A15-2 20°C (68°F) 1.95 to 2.30 kohms A15-1 - A15-2 25°C (77°F) 1.60 to 1.80 kohms A15-1 - A15-2 30°C (86°F) 1.28 to 1.47 kohms A15-1 - A15-2 35°C (95°F) 1.00 to 1.22 kohms A15-1 - A15-2 40°C (104°F) 0.80 to 1.00 kohms A15-1 - A15-2 45°C (113°F) 0.65 to 0.85 kohms A15-1 - A15-2 50°C (122°F) 0.50 to 0.70 kohms A15-1 - A15-2 55°C (131°F) 0.44 to 0.60 kohms A15-1 - A15-2 60°C (140°F) 0.36 to 0.50 kohms NOTE: Even slightly touching the sensor may change the resistance value. Be sure to hold the connector of the sensor. 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 187) ). NG --> See step 11 OK: Go to next step
7. CHECK HARNESS AND CONNECTOR (AMBIENT TEMPERATURE SENSOR - COMBINATION METER) Disconnect the A15 ambient temperature sensor connector. Disconnect the C37 combination meter connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition C37-23 (TX1+) - A15-2 Always Below 1 ohms C37-18 (TEMP) - A15-1 Always Below 1 ohms C37-23 (TX1+) - Body ground Always 10 kohms or higher C37-18 (TEMP) - Body ground Always 10 kohms or higher Reconnect the ambient temperature sensor connector. Reconnect the combination meter connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
8. REPLACE COMBINATION METER Replace the combination meter. Refer to «REMOVAL»(ref-511398-S03938641392012102600000). HINT: Since the combination meter cannot be inspected while it is removed from the vehicle, replace the combination meter with a normal one and check that the condition returns to normal. NEXT: Go to next step
9. CHECK FOR DTC Clear the DTC. Refer to «DTC CHECK / CLEAR»(ref-511402-S00684680972012102600000). Check for DTCs. Refer to «DTC CHECK / CLEAR»(ref-511402-S00684680972012102600000). Result Result Proceed to DTC B1412 is not output A DTC B1412 is output B B --> See step 13 A --> END
10. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-511402-S35284386912012102600000)
11. REPLACE AMBIENT TEMPERATURE SENSOR. Refer to «REMOVAL»(ref-511412-S16397541262012102600000)
12. GO TO DTC B1499. Refer to «DTC B1499: Multiplex Communication Circuit»(ref-511444-S27837751802012102600000)
13. REPLACE AIR CONDITIONING AMPLIFIER. Refer to «REMOVAL»(ref-511412-S04462163122012102600000)

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.

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1. READ VALUE USING TECHSTREAM (EVAPORATOR FIN THERMISTOR) Use the Data List to check if the evaporator fin thermistor is functioning properly. AIR CONDITIONER: Tester Display Measurement Item/Range Normal Condition Diagnostic Note Evaporator Fin Thermistor Evaporator fin thermistor / Min.: -29.7°C (-21.46°F), Max.: 59.55°C (139.19°F) Actual evaporator temperature is 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 the DTC output) C B --> See step 5 C --> See step 4 A: Go to next step
2. INSPECT EVAPORATOR TEMPERATURE SENSOR Disconnect the C32 evaporator temperature sensor connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition C32-1 - C32-2 -10°C (14°F) 7.30 to 9.10 kohms C32-1 - C32-2 -5°C (23°F) 5.65 to 6.95 kohms C32-1 - C32-2 0°C (32°F) 4.40 to 5.35 kohms C32-1 - C32-2 5°C (41°F) 3.40 to 4.15 kohms C32-1 - C32-2 10°C (50°F) 2.70 to 3.25 kohms C32-1 - C32-2 15°C (59°F) 2.14 to 2.58 kohms C32-1 - C32-2 20°C (68°F) 1.71 to 2.05 kohms C32-1 - C32-2 25°C (77°F) 1.38 to 1.64 kohms C32-1 - C32-2 30°C (86°F) 1.11 to 1.32 kohms NOTE: Even slightly touching the sensor may change the resistance value. Be sure to hold the connector of the sensor. 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 190) ). Reconnect the evaporator temperature sensor connector. NG --> See step 6 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - EVAPORATOR TEMPERATURE SENSOR) Disconnect the C32 evaporator temperature sensor connector. Disconnect the C8 A/C amplifier connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition C8-10 (TE) - C32-1 Always Below 1 ohms C8-11 (SG-3) - C32-2 Always Below 1 ohms C8-10 (TE) - Body ground Always 10 kohms or higher C8-11 (SG-3) - Body ground Always 10 kohms or higher Reconnect the A/C amplifier connector. Reconnect the evaporator temperature sensor connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 4
4. REPLACE AIR CONDITIONING AMPLIFIER. Refer to «REMOVAL»(ref-511412-S04462163122012102600000)
5. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-511402-S35284386912012102600000)
6. REPLACE EVAPORATOR TEMPERATURE SENSOR. Refer to «DISASSEMBLY - Step 10»(ref-511412-S04299697002012102600000)

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 pressure sensor, which is installed on the pipe of the high pressure side to detect refrigerant pressure, outputs a refrigerant pressure signal to the A/C amplifier. The A/C amplifier converts this signal to pressure according to the sensor characteristics to control the compressor.

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1. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) Disconnect the A10 A/C pressure sensor connector. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Switch Condition Specified Condition A10-3 (+) - Body ground Ignition switch ON 4.5 to 5.5 V Reconnect the A/C pressure sensor connector. NG --> See step 5 OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT) Disconnect the A10 A/C pressure sensor connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition A10-1 (-) - Body ground Always Below 1 ohms Reconnect the A/C pressure sensor connector. NG --> See step 6 OK: Go to next step
3. INSPECT A/C PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT) Remove the A/C amplifier with connectors still connected. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Switch Condition Specified Condition C8-6 (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. NG --> See step 7 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) or higher 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 operation. 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 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 C8-6 (PRE) - Body ground Ignition switch ON (A/C: ON) 0.7 to 4.8 V Result Result Proceed to OK (When troubleshooting according to DTC) A OK (When troubleshooting according to PROBLEM SYMPTOMS TABLE) B NG C B --> See step 19 C --> See step 13 A --> See step 21
5. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - A/C PRESSURE SENSOR) Disconnect the C8 A/C amplifier connector. Disconnect the A10 A/C pressure sensor connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition A10-3 (+) - C8-1 (S5-3) Always Below 1 ohms A10-1 (S5-3) - Body ground Always 10 kohms or higher Reconnect the A/C amplifier connector. Reconnect the A/C pressure sensor connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 21
6. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - A/C PRESSURE SENSOR) Disconnect the C8 A/C amplifier connector. Disconnect the A10 A/C pressure sensor connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition A10-1 (-) - C8-4 (SG-2) Always Below 1 ohms C8-4 (SG-2) - Body ground Always 10 kohms or higher Reconnect the A/C amplifier connector. Reconnect the A/C pressure sensor connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 21
7. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - A/C PRESSURE SENSOR) Disconnect the C8 A/C amplifier connector. Disconnect the A10 A/C pressure sensor connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition A10-2 (PR) - C8-6 (PRE) Always Below 1 ohms C8-6 (PRE) - Body ground Always 10 kohms or higher Reconnect the A/C amplifier connector. Reconnect the A/C pressure sensor connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
8. CHECK 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 in it. OK Vacuum can be maintained in the A/C system. HINT: If vacuum cannot be maintained in the A/C system, refrigerant may be leaking from it. In this case, it is necessary to repair or replace the leaking part of the A/C system. NG --> See step 12 OK: Go to next step
9. CHARGE REFRIGERANT Add an appropriate amount of refrigerant. Refer to «REPLACEMENT - Step 2»(ref-511412-S16365449842012102600000). NEXT: Go to next step
10. RECHECK DTC Recheck for the DTC 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) or higher 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. Result Result Proceed to DTC B1423 is output A DTC B1423 is not 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 --> END A: Go to next step
11. INSPECT A/C PRESSURE SENSOR Install the manifold gauge set. Disconnect the A10 A/C pressure sensor connector. 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 1 - 2 Refrigerant pressure: 0.39 to 3.187 MPa (57 to 463 psi) 1.0 to 4.8 V Reconnect the A/C pressure sensor connector. NG --> See step 20 OK --> See step 21
12. REPAIR A/C SYSTEM LEAK Identify the area where refrigerant leaks from. Refer to «ON-VEHICLE INSPECTION»(ref-511412-S18650167822012102600000). Repair the identified area of the A/C system. Evacuate the A/C system. NEXT --> See step 22
13. INSPECT COOLING FAN SYSTEM Inspect that the cooling fan operates normally. Refer to «ON-VEHICLE INSPECTION»(/scion/xb/ii-2010-2015/remont/cooling-fan/#engine-cooling-fan-system-inspection__on-vehicle-inspection) . NG --> REPAIR COOLING FAN SYSTEM OK: Go to next step
14. CHARGE REFRIGERANT Use a refrigerant recovery unit to recover refrigerant. Evacuate the A/C system. Add an appropriate amount of refrigerant. Refer to «ON-VEHICLE INSPECTION»(ref-511412-S18650167822012102600000). 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, properly evacuate the system. Add an appropriate amount of refrigerant, and check for the DTC. NEXT: Go to next step
15. RECHECK DTC Recheck for the DTC 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) or higher 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, properly evacuate the system, add an appropriate amount of refrigerant, and check for the DTC. 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 output A DTC B1423 is not output B B --> See step 24 A: Go to next step
16. REPLACE EXPANSION VALVE Replace the expansion valve with a normal one. HINT: Replace the expansion valve with a normal one because the expansion valve is either stuck or clogged. NEXT: Go to next step
17. CHARGE REFRIGERANT Add an appropriate amount of refrigerant. Refer to «ON-VEHICLE INSPECTION»(ref-511412-S18650167822012102600000). NEXT: Go to next step
18. RECHECK DTC Recheck for the DTC 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) or higher 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 pressure is not normal after replacing the expansion valve with a normal 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 23 A --> END
19. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-511402-S35284386912012102600000)
20. REPLACE A/C PRESSURE SENSOR. Refer to «COMPONENTS»(ref-511412-S26560404652012102600000)
21. REPLACE AIR CONDITIONING AMPLIFIER. Refer to «REMOVAL»(ref-511412-S04462163122012102600000)
22. CHARGE REFRIGERANT. Refer to «REPLACEMENT - Step 2»(ref-511412-S16365449842012102600000)
23. REPLACE CONDENSER. Refer to «REMOVAL»(ref-511412-S22217841762012102600000)
24. REPLACE COOLER DRYER. Refer to «DISASSEMBLY - Step 2»(ref-511412-S00648551542012102600000)

In this circuit, the compressor receives a refrigerant compression demand signal from the air conditioning amplifier.

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

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1. INSPECT A/C COMPRESSOR (COMPRESSOR SOLENOID) Disconnect the B7 A/C compressor (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-) 20°C (68°F) 10 to 11 ohms Reconnect the A/C compressor (compressor solenoid) connector. NG --> See step 6 OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (A/C COMPRESSOR - BODY GROUND) Disconnect the B7 A/C compressor (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 Always Below 1 ohms Reconnect the A/C compressor (compressor solenoid) connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (A/C COMPRESSOR - A/C AMPLIFIER) Disconnect the B7 A/C compressor (compressor solenoid) connector. Disconnect the C8 A/C amplifier connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition C8-7 (SOL+) - B7-2 (SOL+) Always Below 1 ohms C8-7 (SOL+) - Body ground Always 10 kohms or higher Result Result Proceed to NG A OK (When troubleshooting according to the PROBLEM SYMPTOMS TABLE) B OK (When troubleshooting according to the DTC) C Reconnect the A/C compressor (compressor solenoid) connector. Reconnect the A/C amplifier connector. B --> See step 4 C --> See step 5 A --> REPAIR OR REPLACE HARNESS OR CONNECTOR
4. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-511402-S35284386912012102600000)
5. REPLACE AIR CONDITIONING AMPLIFIER. Refer to «REMOVAL»(ref-511412-S04462163122012102600000)
6. REPLACE A/C COMPRESSOR. Refer to «REMOVAL»(ref-511412-S03559195072012102600000)

The recirculation damper servo motor and No. 1 heater control (air inlet control switch) are powered through the HTR-IG fuse. Operating No. 1 heater control (air inlet control switch) drives the recirculation damper servo motor to switch between "FRESH" and "RECIRCULATION".

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1. INSPECT FUSE (HTR-IG) Remove the HTR-IG fuse from the main body ECU. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition HTR-IG fuse Always Below 1 ohms NG --> See step 8 OK: Go to next step
2. INSPECT RECIRCULATION DAMPER SERVO MOTOR Remove the recirculation damper servo motor. Apply battery voltage to the terminals and check that the recirculation damper servo motor operates. OK Measurement Condition Specified Condition Positive battery - terminal 5 Negative battery - terminal 2 Turns to the "FRESH" side smoothly. Positive battery - terminal 5 Negative battery - terminal 1 Turns to the "RECIRCULATION" side smoothly. Reinstall the recirculation damper servo motor. NG --> See step 9 OK: Go to next step
3. INSPECT NO. 1 HEATER CONTROL (AIR INLET CONTROL SWITCH) Remove the No. 1 heater control (air inlet control switch). Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Switch Condition Specified Condition C39-3 (FRS) - C39-4 (REC) Air inlet control switch: FREE Below 1 ohms C39-3 (FRS) - C39-4 (REC) Air inlet control switch: LOCK 10 kohms or higher Check that the indicator light comes on. Turn the No. 1 heater control (air inlet control switch) to LOCK. OK Measurement Condition Specified Condition Positive battery - terminal 2 Negative battery - terminal 4 The indicator light comes on. Reinstall the No. 1 heater control (air inlet control switch). NG --> See step 10 OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (RECIRCULATION DAMPER SERVO MOTOR - BATTERY) Disconnect the C38 Recirculation damper servo motor connector. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Switch Condition Specified Condition C38-5 (IG+) - Body ground Ignition switch OFF Below 1 V C38-5 (IG+) - Body ground Ignition switch ON 11 to 14 V Reconnect the Recirculation damper servo motor connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. CHECK HARNESS AND CONNECTOR (NO. 1 HEATER CONTROL (AIR INLET CONTROL SWITCH) - BATTERY) Disconnect the C39 No. 1 heater control (air inlet control switch) connector. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Switch Condition Specified Condition C39-2 (A/C+) - Body ground Ignition switch OFF Below 1 V C39-2 (A/C+) - Body ground Ignition switch ON 11 to 14 V Reconnect the No. 1 heater control (air inlet control switch) connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
6. CHECK HARNESS AND CONNECTOR (NO. 1HEATER CONTROL (AIR INLET CONTROL SWITCH) - BODY GROUND) Disconnect the C39 No. 1 heater control (air inlet control switch) connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition C39-4 (REC) - Body ground Always Below 1 ohms Reconnect the No. 1 heater control (air inlet control switch) connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
7. CHECK HARNESS AND CONNECTOR (NO. 1 HEATER CONTROL - RECIRCULATION DAMPER SERVO MOTOR) Disconnect the C39 No. 1 heater control (air inlet control switch) connector. Disconnect the C38 Recirculation damper servo motor connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition C39-3 (FRS) - C38-2 (FRS) Always Below 1 ohms C39-5 (LED+) - C38-1 (REC) Always Below 1 ohms C39-3 (FRS) - Body ground Always 10 kohms or higher C39-5 (LED+) - Body ground Always 10 kohms or higher Reconnect the No. 1 heater control (air inlet control switch) connector. Reconnect the Recirculation damper servo motor connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 11
8. REPLACE FUSE. Refer to «PARTS LOCATION»(ref-511402-S08389744022012102600000)
9. REPLACE RECIRCULATION DAMPER SERVO MOTOR. Refer to «REMOVAL»(ref-511412-S20958502732012102600000)
10. REPLACE NO. 1 HEATER CONTROL (AIR INLET CONTROL SWITCH). Refer to «DISASSEMBLY - Step 1»(ref-511412-S08831243822012102600000)
11. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-511402-S35284386912012102600000)

When the No. 2 heater control (blower switch) is operated, the HTR relay will turn on to allow current to flow to the blower motor and then the motor will start rotating. Operating the No. 2 heater control (blower switch) switches the current flow between the blower resistor and body ground, thus, shifting the rotation speed of the blower motor.

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Scheme 228

1. INSPECT FUSE (HTR, ECU-IG NO. 2) Remove the HTR fuse from the engine room relay block. Remove the ECU-IG No. 2 fuse from the main body ECU. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition HTR fuse Always Below 1 ohms ECU-IG NO. 2 fuse Always Below 1 ohms Reinstall the HTR and ECU-IG No. 2 fuses. NG --> See step 12 OK: Go to next step
2. INSPECT RELAY (HTR) Remove the HTR relay from the main body ECU. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition 3 - 4 Battery is not applied between terminals 1 and 2 Below 1 ohms 3 - 4 Apply the battery voltage between terminals 1 and 2 10 kohms or higher 3 - 5 Battery is not applied between terminals 1 and 2 10 kohms or higher 3 - 5 Apply the battery voltage between terminals 1 and 2 Below 1 ohms Reinstall the HTR relay. NG --> See step 13 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BATTERY) Disconnect the C8 A/C amplifier connector. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Switch Condition Specified Condition C8-9 (SBLW) - Body ground Ignition switch ON Blower switch: OFF 11 to 14 V C8-9 (SBLW) - Body ground Ignition switch ON Blower switch: ON Below 1 V Reconnect the A/C amplifier connector. NG --> See step 4 OK --> See step 14
4. INSPECT BLOWER MOTOR Remove the blower motor. Connect the positive (+) lead from the battery to terminal 2 and negative (-) to terminal 1, and check that the motor operates. OK The blower motor operates smoothly. NG --> See step 15 OK: Go to next step
5. INSPECT BLOWER RESISTOR Remove the blower resistor. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition C21-1 (HI) - C21-4 (E) Always 3.12 to 3.60 ohms C21-3 (M2) - C21-4 (E) Always 1.45 to 1.67 ohms C21-2 (M1) - C21-4 (E) Always 0.52 to 0.60 ohms Reinstall the blower resistor. NG --> See step 16 OK: Go to next step
6. INSPECT NO. 2 HEATER CONTROL (BLOWER SWITCH) Remove the No. 2 heater control (blower switch). Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Switch Condition Specified Condition C40-4 (LO), C40-6 (HI), C40-9 (M1), C40-10 (M2) - C40-5 (E) Blower switch: OFF 10 kohms or higher C40-4 (LO) - C40-5 (E) Blower switch: LO Below 1 ohms C40-4 (LO), C40-9 (M1) - E70-5 (E) Blower switch: M1 Below 1 ohms C40-4 (LO), C40-10 (M2) - C40-5 (E) Blower switch: M2 Below 1 ohms C40-4 (LO), C40-6 (HI) - C40-5 (E) Blower switch: HI Below 1 ohms Reinstall the No. 2 heater control (blower switch). NG --> See step 18 OK: Go to next step
7. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BATTERY) Disconnect the C8 A/C amplifier connector. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Switch Condition Specified Condition C8-9 (SBLW) - Body ground Ignition switch ON 11 to 14 V C8-9 (SBLW) - Body ground Ignition switch OFF Below 1 V Reconnect the A/C amplifier connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
8. CHECK HARNESS AND CONNECTOR (NO. 2 HEATER CONTROL (BLOWER SWITCH) - BATTERY) Disconnect the C40 No. 2 heater control (blower switch) connector. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Switch Condition Specified Condition C40-4 (LO) - Body ground Ignition switch ON 11 to 14 V C40-4 (LO) - Body ground Ignition switch OFF Below 1 V Reconnect the No. 2 heater control (blower switch) connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
9. CHECK HARNESS AND CONNECTOR (BLOWER RESISTOR - NO. 2 HEATER CONTROL (BLOWER SWITCH)) Disconnect the C21 blower resistor connector. Disconnect the C40 No. 2 heater control (blower switch) connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition C21-1 (HI) - C40-6 (HI) Always Below 1 ohms C21-3 (M2) - C40-10 (M2) Always Below 1 ohms C21-2 (M1) - C40-9 (M1) Always Below 1 ohms C21-4 (E) - Body ground Always Below 1 ohms C40-5 (E) - Body ground Always Below 1 ohms C21-1 (HI) - Body ground Always 10 kohms or higher C21-3 (M2) - Body ground Always 10 kohms or higher C21-2 (M1) - Body ground Always 10 kohms or higher Reconnect the blower resistor connector. Reconnect the No. 2 heater control (blower switch) connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
10. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BLOWER RESISTOR, NO. 2 HEATER CONTROL) Disconnect the C19 blower motor connector. Disconnect the C21 blower resistor connector. Disconnect the C40 No. 2 heater control (blower switch) connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition C19-1 - C21-1 (HI) Always Below 1 ohms C19-1 - C40-6 (HI) Always Below 1 ohms C19-1 - Body ground Always 10 kohms or higher Reconnect the blower motor connector. Reconnect the blower resistor connector. Reconnect the No. 2 heater control (blower switch) connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
11. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BATTERY, BODY GROUND) Disconnect the C19 blower motor connector. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Switch Condition Specified Condition C19-2 - Body ground Ignition switch ON Blower switch: OFF Below 1 V C19-2 - Body ground Ignition switch ON Blower switch: ON 11 to 14 V Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Switch Condition Specified Condition C19-2 - Body ground Ignition switch OFF Blower switch: OFF Below 1 ohms Reconnect the blower motor connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 17
12. REPLACE FUSE. Refer to «PARTS LOCATION»(ref-511402-S08389744022012102600000)
13. REPLACE HTR RELAY. Refer to «PARTS LOCATION»(ref-511402-S08389744022012102600000)
14. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-511402-S35284386912012102600000)
15. REPLACE BLOWER MOTOR. Refer to «REMOVAL»(ref-511412-S34862949542012102600000)
16. REPLACE BLOWER RESISTOR. Refer to «REMOVAL»(ref-511412-S12862417822012102600000)
17. CHECK INTERMITTENT PROBLEMS. Refer to «HOW TO PROCEED WITH TROUBLESHOOTING»(ref-511289-S32292085502012102600000)
18. REPLACE NO. 2 HEATER CONTROL. Refer to «DISASSEMBLY - Step 2»(ref-511412-S08831243822012102600000)

The No. 3 heater control is powered through the HTR-IG fuse. The No. 3 heater control transmits operational signals of each switch to the A/C amplifier.

Scheme 229

Scheme 230

Scheme 231

Scheme 232

1. INSPECT FUSE (HTR-IG) Remove the HTR-IG fuse from the main body ECU. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified condition HTR-IG fuse Always Below 1 ohms NG --> See step 5 OK: Go to next step
2. INSPECT NO. 3 HEATER CONTROL Measure the resistance. Remove the No. 3 heater control. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Switch Condition Specified Condition C20-2 (B) - C20-3 (A/C) Heater control base (A/C): LOCK Below 1 ohms C20-2 (B) - C20-3 (A/C) Heater control base (A/C): FREE 10 kohms or higher Check that the indicator light comes on. Connect the positive (+) lead from the battery to terminal 3 and negative (-) to terminal 4, and check that the indicator light comes on. OK The indicator light comes on. Reinstall the No. 3 heater control. NG --> See step 6 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (NO. 3 HEATER CONTROL - BATTERY) Disconnect the C20 No. 3 heater control connector. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Switch Condition Specified condition C20-2 (B) - Body ground Ignition switch ON 11 to 14 V C20-2 (B) - Body ground Ignition switch OFF Below 1 V Reconnect the No. 3 heater control connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (NO. 3 HEATER CONTROL - A/C AMPLIFIER) Disconnect the C20 No. 3 heater control connector. Disconnect the C8 A/C amplifier connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester connection Condition Specified condition C20-3 (A/C) - C8-15 (A/C) Always Below 1 ohms C20-4 (AIND) - C8-16 (LED) Always Below 1 ohms C20-3 (A/C) - Body ground Always 10 kohms or higher C20-4 (AIND) - Body ground Always 10 kohms or higher Reconnect the No. 3 heater control connector. Reconnect the A/C amplifier connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 7
5. REPLACE FUSE. Refer to «PARTS LOCATION»(ref-511402-S08389744022012102600000)
6. REPLACE NO. 3 HEATER CONTROL. Refer to «DISASSEMBLY - Step 3»(ref-511412-S08831243822012102600000)
7. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-511402-S35284386912012102600000)

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

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

Scheme 233

See also:
• ON-VEHICLE INSPECTION