Air Conditioning (Diagnostic Codes & Circuit Tests): Overview Scion xD I

DESCRIPTION

The ambient temperature sensor is installed in the front part of the condenser to detect the ambient temperature and control the air conditioner. The sensor is connected to the air conditioning amplifier and detects fluctuations in the ambient temperature. This data is used for controlling the room temperature. The sensor sends a signal to the air conditioning amplifier. The resistance of the ambient temperature sensor changes in accordance with the ambient temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases. The air conditioning amplifier applies a voltage (5 V) to the ambient temperature sensor and reads voltage changes as the resistance of the ambient temperature sensor changes.

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1. READ VALUE USING TECHSTREAM (AMBIENT TEMPERATURE SENSOR) Connect the Techstream to DLC3. Turn the ignition switch to ON. Turn the tester on. Select the following menus: Body Electrical / Air Conditioner / Data List / Ambient Temp Sensor According to the display on tester, read the "Data List". Ambient Temp Sensor Tester Display Measurement Item/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: -3.3°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 trouble shooting according to the DTC output) C C --> See step 6 B --> See step 4 A: Go to next step
2. INSPECT AMBIENT TEMPERATURE SENSOR Remove the ambient temperature sensor. Refer to «REMOVAL»(ref-388752-S13967690412011031100000). Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition 1 - 2 10°C (50°F) 3.00 to 3.73 kohms 1 - 2 15°C (59°F) 2.45 to 2.88 kohms 1 - 2 20°C (68°F) 1.95 to 2.30 kohms 1 - 2 25°C (77°F) 1.60 to 1.80 kohms 1 - 2 30°C (86°F) 1.28 to 1.47 kohms 1 - 2 35°C (95°F) 1.00 to 1.22 kohms 1 - 2 40°C (104°F) 0.80 to 1.00 kohms 1 - 2 45°C (113°F) 0.65 to 0.85 kohms 1 - 2 50°C (122°F) 0.50 to 0.70 kohms 1 - 2 55°C (131°F) 0.44 to 0.60 kohms 1 - 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 in (Scheme 188) ). Reinstall the ambient temperature sensor. NG --> See step 5 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (AMBIENT TEMPERATURE SENSOR - COMBINATION METER) Disconnect the B4 ambient temperature sensor connector. Disconnect the G7 air conditioning amplifier connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition G7-5 (TAM) - B4-2 Always Below 1 ohms G7-11 (SG-1) - B4-1 Always Below 1 ohms G7-5 (TAM) - Body ground Always 10 kohms or higher G7-11 (SG-1) - Body ground Always 10 kohms or higher Reconnect the ambient temperature sensor connector. Reconnect the air conditioning amplifier connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 6
4. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-388750-S14189559692011031100000)
5. REPLACE AMBIENT TEMPERATURE SENSOR. Refer to «REMOVAL»(ref-388752-S13967690412011031100000)
6. REPLACE AIR CONDITIONING AMPLIFIER. Refer to «REMOVAL»(ref-388752-S16681480862011031100000)

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 air conditioning 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 air conditioning 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) Connect the Techstream to the DLC3. Turn the ignition switch to ON. Turn the tester on. Select the following menus: Body Electrical / Air Conditioner / Data List / Evaporator Fin Thermistor According to the display on tester, read the "Data List". Evaporator Fin Sensor 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 C --> See step 5 B --> See step 4 A: Go to next step
2. INSPECT EVAPORATOR TEMPERATURE SENSOR Disconnect the G2 evaporator temperature sensor connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition 1 - 2 -10°C (14°F) 7.30 to 9.10 kohms 1 - 2 -5°C (23°F) 5.65 to 6.95 kohms 1 - 2 0°C (32°F) 4.40 to 5.35 kohms 1 - 2 5°C (41°F) 3.40 to 4.15 kohms 1 - 2 10°C (50°F) 2.70 to 3.25 kohms 1 - 2 15°C (59°F) 2.14 to 2.58 kohms 1 - 2 20°C (68°F) 1.71 to 2.05 kohms 1 - 2 25°C (77°F) 1.38 to 1.64 kohms 1 - 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 in (Scheme 191) ). Reconnect the evaporator temperature sensor connector. NG --> See step 6 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - EVAPORATOR TEMPERATURE SENSOR) Disconnect the G2 evaporator temperature sensor connector. Disconnect the G7 air conditioning amplifier connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition G7-10 (TE) - G2-2 Always Below 1 ohms G7-4 (SG-2) - G2-1 Always Below 1 ohms G7-10 (TE) - Body ground Always 10 kohms or higher G7-4 (SG-2) - Body ground Always 10 kohms or higher Reconnect the air conditioning amplifier connector. Reconnect the evaporator temperature sensor connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 5
4. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-388750-S14189559692011031100000)
5. REPLACE AIR CONDITIONING AMPLIFIER. Refer to «REMOVAL»(ref-388752-S16681480862011031100000)
6. REPLACE EVAPORATOR TEMPERATURE SENSOR. Refer to «REMOVAL»(ref-388752-S42529439672011031100000)

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 air conditioning amplifier. The air conditioning amplifier converts this signal to pressure according to the sensor characteristics to control the compressor.

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1. CHECK REFRIGERANT PRESSURE Install the manifold gauge set. Refer to «ON-VEHICLE INSPECTION - Step 2»(ref-388752-S03382238152011031100000). Read the manifold gauge pressure when the following conditions are established. Prepare the vehicle in accordance with the chart below. Item Condition Engine speed 1500 RPM Vehicle doors Fully open Temperature setting MAX COLD Blower speed HI A/C switch ON Air inlet RECIRC When the refrigerant volume is correct, the gauge reading indicates as follows: Low pressure side 0.15 to 0.25 MPa (1.5 to 2.5 kgf/cm 2, 22 to 36 psi) High pressure side 1.37 to 1.57 MPa (14 to 16 kgf/cm 2, 199 to 228 psi) HINT: Pressure varies in accordance with certain conditions (outside air temperature, sunlight and wind). NG --> See step 5 OK: Go to next step
2. READ VALUE USING TECHSTREAM (REGULATOR PRESSURE SENSOR) Warm up the engine. Turn the ignition switch to OFF. Connect the Techstream to the DLC3. Turn the ignition switch to ON. Turn the tester on. Select the following menus: Body Electrical / Air Conditioner / Data List / According to the display on tester, read the "Data List". Regulator Pressure Sensor Tester Display Measurement Item/Range Normal Condition Diagnostic Note Regulator Pressure Sensor Regulator pressure sensor / Min.: 0 kgf/cm2G, Max.: 38.25 kgf/ cm2G Actual refrigerant pressure is 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 the DTC output) C C --> See step 13 B --> See step 11 A: Go to next step
3. INSPECT AIR CONDITIONING PRESSURE SENSOR Install the manifold gauge set. Refer to «ON-VEHICLE INSPECTION»(ref-388752-S12574679222011031100000). Disconnect the A1 air conditioning 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 (4 to 32.5 kgf/cm 2, 57 to 463 psi) 1.0 to 4.8 V Reconnect the air conditioning pressure sensor connector. NG --> See step 12 OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER) Disconnect the A1 air conditioning pressure sensor connector. Disconnect the G7 air conditioning amplifier connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition A1-1 (-) - G7-11 (SG-1) Always Below 1 ohms A1-2 (PR) - G7-6 (PRE) Always Below 1 ohms A1-3 (+) - G7-1 (S5-3) Always Below 1 ohms A1-1 (-) - Body ground Always 10 kohms or higher A1-2 (PR) - Body ground Always 10 kohms or higher A1-3 (+) - Body ground Always 10 kohms or higher Reconnect the air conditioning amplifier connector. Reconnect the air conditioning pressure sensor connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 13
5. CHECK FOR A/C SYSTEM LEAK Install the manifold gauge set. Refer to «ON-VEHICLE INSPECTION»(ref-388752-S12574679222011031100000). 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 8 OK: Go to next step
6. CHARGE REFRIGERANT Add an appropriate amount of refrigerant. Refer to «REPLACEMENT - Step 2»(ref-388752-S16248572282011031100000). NEXT: Go to next step
7. 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 --> See step 13
8. REPAIR A/C SYSTEM LEAK Identify the area where refrigerant leaks from. Refer to «REPLACEMENT»(ref-388752-S16733690332011031100000). Repair the identified area of the A/C system. Evacuate the A/C system. NEXT: Go to next step
9. CHARGE REFRIGERANT Use a refrigerant recovery unit to recover refrigerant. Evacuate the A/C system. Add an appropriate amount of refrigerant. Refer to «REPLACEMENT»(ref-388752-S16733690332011031100000). HINT: If refrigerant is added and the system has not been properly evacuated (insufficient vacuum time), moisture in the air remaining in the system may 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
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. If refrigerant is added and the system has not been properly evacuated (insufficient vacuum time), moisture in the air remaining in the system may 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 --> END A --> See step 13
11. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-388750-S14189559692011031100000)
12. REPLACE AIR CONDITIONING PRESSURE SENSOR. Refer to «REMOVAL»(ref-388752-S42947971062011031100000)
13. REPLACE AIR CONDITIONING AMPLIFIER. Refer to «REMOVAL»(ref-388752-S16681480862011031100000)

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 C8 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 1 (SOL+) - 2 (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 C8 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 C8-2 (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 - AIR CONDITIONING AMPLIFIER) Disconnect the C8 A/C compressor (compressor solenoid) connector. Disconnect the G7 air conditioning amplifier connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition G7-7 (SOL+) - C8-1 (SOL+) Always Below 1 ohms G7-7 (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 air conditioning amplifier connector. 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-388750-S14189559692011031100000)
5. REPLACE AIR CONDITIONING AMPLIFIER. Refer to «REMOVAL»(ref-388752-S16681480862011031100000)
6. REPLACE A/C COMPRESSOR. Refer to «REMOVAL»(ref-388752-S38482897292011031100000)

When the heater control (blower switch) is set to position 1 or higher, the contact of the HTR relay is closed, current flows to the blower motor, and the blower motor operates. The blower motor speed can be changed by exchanging the ground and the blower resistor circuit with the heater control (blower switch).

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1. INSPECT FUSES (GAUGE, HTR) Remove the HTR fuse from the engine room relay block. Remove the GAUGE 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 GAUGE fuse Always Below 1 ohms Reinstall the GAUGE fuse. Reinstall the HTR fuse. NG --> See step 12 OK: Go to next step
2. INSPECT HTR RELAY 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 Voltage is not applied between terminals 1 and 2 Below 1 ohms 3 - 5 Voltage is not applied between terminals 1 and 2 10 kohms or higher 3 - 4 Apply the battery voltage 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. INSPECT BLOWER MOTOR Remove the blower motor. Refer to «REMOVAL»(ref-388752-S39472991652011031100000). Apply battery voltage to the terminals and check that the blower motor operates. OK Tester Connection Specified Condition Positive battery - 2 Negative battery - 1 The blower motor operates smoothly. Reinstall the blower motor. NG --> See step 14 OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (HTR FUSE - MAIN BODY ECU) Disconnect the 4L main body ECU connector. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Condition Specified Condition 4L-1 - Body ground Always 11 to 14 V Reconnect the main body ECU connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. INSPECT MAIN BODY ECU Remove the HTR relay from the main body ECU. Disconnect the 4E and 4F main body ECU connectors. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition 4E-17 - HTR-4 Always Below 1 ohms 4F-7 - HTR-3 Always Below 1 ohms Reconnect the main body ECU connectors. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Condition Specified Condition HTR-5 - Body ground Always 11 to 14 V Reinstall the HTR relay. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Condition Specified Condition 4Q-5 - Body ground Ignition switch ON 11 to 14 V NG --> REPLACE MAIN BODY ECU OK: Go to next step
6. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - NO. 2 HEATER CONTROL) Disconnect the G1 No. 2 heater control connector. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Switch Condition Specified Condition G1-9 (LO) - Body ground Ignition switch ON 11 to 14 V Reconnect the No. 2 heater control connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
7. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - BLOWER MOTOR) Disconnect the G4 blower motor connector. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Switch Condition Specified Condition G4-2 - Body ground Ignition switch ON Blower switch ON 11 to 14 V Reconnect the blower motor connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
8. CHECK HARNESS AND CONNECTOR (BLOWER RESISTOR - BLOWER MOTOR) Disconnect the G3 blower resistor connector. Disconnect the G4 blower motor connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition G3-4 - G4-1 Always Below 1 ohms Reconnect the blower resistor connector. Reconnect the blower motor connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
9. INSPECT BLOWER RESISTOR Remove the blower resistor. Refer to «REMOVAL»(ref-388752-S20200520062011031100000). Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition 1 - 4 Always 3.12 to 3.60 ohms 2 - 4 Always 0.52 to 0.60 ohms 3 - 4 Always 1.45 to 1.67 ohms Reinstall the blower resistor. NG --> See step 15 OK: Go to next step
10. INSPECT NO. 2 HEATER CONTROL (BLOWER SWITCH) Remove the No. 2 heater control. Refer to «DISASSEMBLY - Step 2»(ref-388752-S17046979562011031100000). Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Switch Condition Specified Condition ALL - 5 (E) 0 10 kohms or higher 5 (E) - 9 (LO) 1 Below 1 ohms 5 (E) - 7 (M1) - 9 (LO) 1 - 2 Below 1 ohms 5 (E) - 7 (M1) - 9 (LO) 2 Below 1 ohms 5 (E) - 6 (M2) - 7 (M1) - 9 (LO) 2 -3 Below 1 ohms 5 (E) - 6 (M2) - 9 (LO) 3 Below 1 ohms 5 (E) - 6 (M2) - 9 (LO) - 10(HI) 3 - 4 Below 1 ohms 5 (E) - 9 (LO) - 10(HI) 4 Below 1 ohms Reinstall the No. 2 heater control. NG --> See step 16 OK: Go to next step
11. CHECK HARNESS AND CONNECTOR (NO. 2 HEATER CONTROL - BLOWER RESISTOR) Disconnect the G1 No. 2 heater control connector. Disconnect the G3 blower resistor connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition G1-5 (E) - G3-1 Always Below 1 ohms G1-6 (M2) - G3-2 Always Below 1 ohms G1-7 (M1) - G3-3 Always Below 1 ohms G1-10 (HI) - G3-4 Always Below 1 ohms Reconnect the No. 2 heater control connector. Reconnect the blower resistor connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPAIR OR REPLACE HARNESS OR CONNECTOR (BLOWER RESISTOR - BODY GROUND)
12. REPLACE FUSE. Refer to «PARTS LOCATION»(ref-388750-S17418724372011031100000)
13. REPLACE HTR RELAY. Refer to «PARTS LOCATION»(ref-388750-S17418724372011031100000)
14. REPLACE BLOWER MOTOR. Refer to «REMOVAL»(ref-388752-S39472991652011031100000)
15. REPLACE BLOWER RESISTOR. Refer to «REMOVAL»(ref-388752-S20200520062011031100000)
16. REPLACE NO. 2 HEATER CONTROL. Refer to «DISASSEMBLY - Step 2»(ref-388752-S17046979562011031100000)

The No. 1 heater control is powered through the A/C fuse. The No. 1 heater control transmits operational signals of each switch to the air conditioning amplifier.

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1. INSPECT FUSE (A/C) Remove the A/C 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 A/C fuse Always Below 1 ohms Reinstall the A/C fuse. NG --> See step 5 OK: Go to next step
2. INSPECT NO. 1 HEATER CONTROL Remove the No. 1 heater control. Refer to «DISASSEMBLY - Step 3»(ref-388752-S17046979562011031100000). Measure the resistance. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Switch Condition Specified Condition 2 (L) - 4 (E) A/C Switch: off 10 kohms or higher 2 (L) - 4 (E) A/C Switch: on Below 1 ohms Check that the indicator light comes on. OK Tester Connection Switch Condition Specified Condition Positive battery - 2 (L) Negative battery - 3 (E) A/C Switch: Off Indicator light off A/C Switch: On Indicator light comes on Reinstall the No. 1 heater control. NG --> See step 6 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (NO. 1 HEATER CONTROL - BATTERY) Disconnect the G5 No. 1 heater control connector. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Switch Condition Specified Condition G5-2 (L) - Body ground Ignition switch OFF Below 1 V G5-2 (L) - Body ground Ignition switch ON 11 to 14 V Reconnect the No. 1 heater control connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (NO. 1 HEATER CONTROL - AIR CONDITIONING AMPLIFIER) Disconnect the G5 No. 1 heater control connector. Disconnect the G8 air conditioning amplifier connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition G5-3 (E) - G7-16 (LED) Always Below 1 ohms G5-4 (B) - G7-15 (A/C) Always Below 1 ohms G5-3 (E) - Body ground Always 10 kohms or higher G5-4 (B) - Body ground Always 10 kohms or higher Reconnect the No. 1 heater control connector. Reconnect the air conditioning amplifier connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 7
5. REPLACE FUSE. Refer to «PARTS LOCATION»(ref-388750-S17418724372011031100000)
6. REPLACE NO. 1 HEATER CONTROL. Refer to «DISASSEMBLY - Step 1»(ref-388752-S17046979562011031100000)
7. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-388750-S14189559692011031100000)

PTC heater relays are closed in accordance with signals from the air conditioning amplifier assembly and power is supplied to the PTC heater assembly installed on the radiator heater unit.

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1. INSPECT FUSES (HTR SUB 1, HTR SUB 2) Remove the HTR SUB 1 and HTR SUB 2 fuses from the engine room relay block. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition HTR SUB 1 fuse Always Below 1 ohms HTR SUB 2 fuse Always Below 1 ohms Reinstall the HTR SUB 1 and HTR SUB 2 fuses. NG --> REPLACE FUSE OK: Go to next step
2. INSPECT HTR SUB RELAY (HTR SUB 1, HTR SUB 2, HTR SUB 3) Remove the HTR SUB 1 relay from the engine room relay block. Remove the HTR SUB 2 and HTR SUB 3 relays from the No. 2 engine room relay block. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition 3 - 5 Voltage 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 SUB 1 relay. Reinstall the HTR SUB 2 and HTR SUB 3 relays. NG --> REPLACE HTR SUB RELAY OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (FUSE - PTC HEATER RELAY) Remove the HTR SUB 1 relay from the engine room relay block. Remove the HTR SUB 2 and HTR SUB 3 relays from the No. 2 engine room relay block. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Condition Specified Condition HTR SUB 1-5 - Body ground Always 11 to 14 V HTR SUB 2-5 - Body ground Always 11 to 14 V HTR SUB 3-5 - Body ground Always 11 to 14 V Reinstall the HTR SUB 1 relay. Reinstall the HTR SUB 2 and HTR SUB 3 relays. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - BODY GROUND) Remove the HTR SUB 1 relay from the engine room relay block. Remove the HTR SUB 2 and HTR SUB 3 relays from the No. 2 engine room relay block. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition HTR SUB 1-1 - Body ground Always Below 1 ohms HTR SUB 2-1 - Body ground Always Below 1 ohms HTR SUB 3-1 - Body ground Always Below 1 ohms Reinstall the HTR SUB 1 relay. Reinstall the HTR SUB 2 and HTR SUB 3 relays. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. PERFORM ACTIVE TEST USING TECHSTREAM (HEATER ACTIVE LEVEL) Remove the HTR SUB 1 relay from the engine room relay block. Remove the HTR SUB 2 and HTR SUB 3 relays from the No. 2 engine room relay block. Connect the Techstream to the DLC3. Turn the ignition switch to ON. Turn the tester on. Select the following menus: Body Electrical / Air Conditioner / Active Test / Heater Active Level Measure the voltage when changing the control range with a Techstream, according to the value(s) in the table below. Standard voltage Tester Connection Condition Specified Condition HTR SUB 1-2 - Body ground Heater Active Level 0 Below 1 V Heater Active Level 1 11 to 14 V Heater Active Level 2 11 to 14 V Heater Active Level 3 11 to 14 V HTR SUB 2-2 - Body ground Heater Active Level 0 Below 1 V Heater Active Level 1 Below 1 V Heater Active Level 2 11 to 14 V Heater Active Level 3 11 to 14 V HTR SUB 3-2 - Body ground Heater Active Level 0 Below 1 V Heater Active Level 1 Below 1 V Heater Active Level 2 Below 1 V Heater Active Level 3 11 to 14 V Reinstall the HTR SUB1 relay. Reinstall the HTR SUB2 and HTR SUB3 relays. NG --> See step 8 OK: Go to next step
6. INSPECT PTC HEATER ASSEMBLY Disconnect the A18 PTC heater assembly connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition 1 - Ground terminal Always Below 1 ohms 2 - Ground terminal Always Below 1 ohms 3 - Ground terminal Always Below 1 ohms Reconnect the PTC heater assembly connector. NG --> See step 9 OK: Go to next step
7. PERFORM ACTIVE TEST USING TECHSTREAM (HEATER ACTIVE LEVEL) Disconnect the A18 PTC heater assembly connector. Connect the Techstream to the DLC3. Turn the ignition switch to ON. Turn the tester on. Select the following menus: Body Electrical / Air Conditioner / Active Test / Heater Active Level Measure the voltage when changing the control range with a Techstream, according to the value(s) in the table below. Standard voltage. Tester Connection Condition Specified Condition A18-1 - Body ground Heater Active Level 0 Below 1 V Heater Active Level 1 Below 1 V Heater Active Level 2 Below 1 V Heater Active Level 3 11 to 14V A18-2 - Body ground Heater Active Level 0 Below 1 V Heater Active Level 1 11 to 14V Heater Active Level 2 11 to 14V Heater Active Level 3 11 to 14V A18-3 - Body ground Heater Active Level 0 Below 1 V Heater Active Level 1 Below 1 V Heater Active Level 2 11 to 14V Heater Active Level 3 11 to 14V Reconnect the PTC heater assembly connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR (HTR SUB RELAY - PTC HEATER) OK --> See step 11
8. CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - AIR CONDITIONING AMPLIFIER) Remove the HTR SUB 1 relay from the engine room relay block. Remove the HTR SUB 2 and HTR SUB 3 relays from the No. 2 engine room relay block. Disconnect the G8 air conditioning amplifier connector. Measure the resistance. Standard resistance Tester Connection Condition Specified Condition HTR SUB 1-2 - G8-9 (PTC1) Always Below 1 ohms HTR SUB 2-2 - G8-10 (PTC2) Always Below 1 ohms HTR SUB 3-2 - G8-12 (PTC3) Always Below 1 ohms Reinstall the HTR SUB 1 relay. Reinstall the HTR SUB 2 and HTR SUB 3 relays. Reconnect the air conditioning amplifier connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 10
9. REPLACE PTC HEATER ASSEMBLY. Refer to «DISASSEMBLY - Step 5»(ref-388752-S32340465062011031100000)
10. REPLACE AIR CONDITIONING AMPLIFIER. Refer to «REMOVAL»(ref-388752-S16681480862011031100000)
11. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-388750-S14189559692011031100000)

The air conditioning amplifier receives headlight operational signals to determine electrical load conditions. The electrical load condition signals are used for controlling the number of the PTC heater elements to be heated.

Scheme 225

Scheme 226

1. INSPECT HEADLIGHT ASSEMBLY Check that the headlight comes on when the light control switch is turned to the HEAD position. OK The headlight comes on. NG --> See step 4 OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (H-LP RELAY - AIR CONDITIONING AMPLIFIER) Disconnect the G8 air conditioning amplifier connector. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Switch Condition Specified Condition G8-23 (HLS) - Body ground Light control switch: OFF 11 to 14 V G8-23 (HLS) - Body ground Light control switch: HEAD Below 1 V Reconnect the air conditioning amplifier connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 3
3. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-388750-S14189559692011031100000)
4. GO TO LIGHTING SYSTEM. Refer to «Headlight Relay Circuit»(ref-388783-S16234318442011031100000)

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

Scheme 227

Scheme 228

1. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - GENERATOR) Disconnect the G8 air conditioning amplifier connector. Disconnect the C9 generator connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester connection Condition Specified condition G8-24 (ALT) - C9-3 (M) Always Below 1 ohms G8-24 (ALT) - Body ground Always 10 kohms or higher Reconnect the generator connector. Disconnect the air conditioning amplifier connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
2. INSPECT GENERATOR Inspect the generator. Refer to «INSPECTION»(/scion/xd/i-2007-2014/remont/charging-system/#charging-service-information) for ON-VEHICLE INSPECTION. Refer to «INSPECTION»(/scion/xd/i-2007-2014/remont/charging-system/#charging-service-information) for INSPECTION. NG --> See step 4 OK --> See step 3
3. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-388750-S14189559692011031100000)
4. REPLACE GENERATOR. Refer to «REMOVAL»(/scion/xd/i-2007-2014/remont/charging-system/#charging-service-information)

The main power source is supplied to the air conditioning amplifier when the ignition switch is turned to ON.

The power source is used for operating the air conditioning amplifier and servo motor, etc.

Scheme 229

See also:
• INSPECTION