Air Conditioning: Overview Toyota Yaris II

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1. IF ANY OF FOLLOWING CONDITIONS ARE MET, KEEP ENGINE IDLING WITH A/C ON (ENGINE SPEED AT LESS THAN 2000 RPM) FOR AT LEAST 1 MINUTE: Refrigerant gas has been refilled or A/C parts have been replaced. Long time has elapsed since engine was stopped. NOTE: If the engine speed exceeds 2,000 RPM, the A/C compressor may be damaged.
2. DO NOT HANDLE REFRIGERANT IN ENCLOSED AREAS OR NEAR OPEN FLAMES
3. ALWAYS WEAR EYE PROTECTION (Scheme 1): Precaution For Handling Refrigerant In Enclosed Area
4. BE CAREFUL NOT TO GET LIQUID REFRIGERANT IN YOUR EYES OR ON YOUR SKIN If liquid refrigerant gets in your eyes or on your skin: Wash the area with lots of cold water. CAUTION: Do not rub your eyes or skin. Apply clean petroleum jelly to the skin. Go immediately to a hospital or see a physician for professional treatment. (Scheme 2): Precaution For Protecting Eyes From Liquid Refrigerant
5. NEVER HEAT CONTAINER OR EXPOSE IT TO NAKED FLAMES
6. BE CAREFUL NOT TO DROP CONTAINER OR SUBJECT IT TO PHYSICAL SHOCKS
7. DO NOT OPERATE COMPRESSOR WITH INSUFFICIENT REFRIGERANT IN REFRIGERANT SYSTEM If there is not enough refrigerant in the refrigerant system, oil lubrication will be insufficient and compressor burnout may occur. Necessary care should be taken to avoid this.
8. DO NOT OPEN HIGH PRESSURE MANIFOLD VALVE WHILE COMPRESSOR IS OPERATING Open and close only the low pressure valve. Opening and closing the high pressure valve could cause the charging cylinder to rupture. (Scheme 3): Identifying High And Low Pressure Valve
9. BE CAREFUL NOT TO OVERCHARGE SYSTEM WITH REFRIGERANT If the refrigerant is overcharged, it causes problems such as insufficient cooling, poor fuel economy and engine overheating.
10. DO NOT OPERATE ENGINE AND COMPRESSOR WITHOUT REFRIGERANT CAUTION: This may damage the inside of the compressor.

Communication table

COMMUNICATION CHART

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1. GENERAL The air conditioning system has the following features: The air conditioning amplifier controls the operation of parts, such as the air conditioning compressor, automatically in accordance with the operating conditions of the air conditioning system.
2. MODE POSITION AND DAMPER OPERATION (Scheme 4): Model Position And Damper Operation Diagram MODE POSITION AND DAMPER OPERATION Control Damper Control Position Damper Position Operation Air Inlet Control Damper FRESH A Allows outside air to enter. RECIRC B Recirculates internal air. Air Mix Control Damper COOL to HOT C, D Continuously changes mix ratio of warm and cool air between COOL and HOT. Mode Control Damper M, L, E, J Blows air from center register and side registers. N, R, F, J Blows air from center register, side registers, front footwell register and rear footwell register. O, K, F, I Blows air from side registers, front footwell register, and rear footwell register. Also, blows some air from front defroster. O, K, G, H Blows air from front defroster, side registers, front footwell register, and rear footwell register. O, R, E, Q Blows air from front defroster and side registers.
3. AIR OUTLET AND AIR FLOW VOLUME (Scheme 5): Identifying Air Outlets

The circle size (O) indicates the proportion of the flow volume.

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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 changes in the resistance of the ambient temperature sensor.

DTC DETECTION CONDITION AND TROUBLE AREA REFERENCE

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1. READ VALUE USING INTELLIGENT TESTER (AMBI TEMP SENS) Connect the intelligent tester with CAN VIM to the DLC3. Turn the ignition switch ON and turn the intelligent tester main switch ON. Select the item below in the DATA LIST, and read the value displayed on the intelligent tester. DATA LIST / AIR CONDITIONER DATA LIST - AIR CONDITIONER Item Measurement Item / Display (Range) Normal Condition Diagnostic Note AMBI TEMP SENS Ambient temperature sensor / Min.: -23.3°C (-9.94°F) Max.: 65.95°C(150.71°F) Actual ambient temperature is displayed Open circuit: -23.3°C (-9.94°F) Short circuit: 65.95°C (150.71 °F) OK: The display is as specified in the normal condition column. Result RESULT REFERENCE Result Proceed to NG A OK (Checking from the «PROBLEM SYMPTOMS TABLE»(ref-267417-S35547163962007101100000) ) B OK (Checking from the DTC) C B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN «PROBLEM SYMPTOMS TABLE»(ref-267417-S35547163962007101100000) C: REPLACE AIR CONDITIONING AMPLIFIER A: GO TO NEXT STEP
2. INSPECT AMBIENT TEMPERATURE SENSOR Remove the ambient temperature sensor. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION 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: Touching the sensor even slightly 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 on the left). Reinstall the ambient temperature sensor. NG: REPLACE AMBIENT TEMPERATURE SENSOR see scheme 21: Identifying Ambient Temperature Sensor Connector Terminals And Graph OK: GO TO NEXT STEP
3. CHECK HARNESS AND CONNECTOR (AMBIENT TEMPERATURE SENSOR AIR CONDITIONING AMPLIFIER) Disconnect the B5 ambient temperature sensor connector. Disconnect the E8 air conditioning amplifier connector. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition B5-1-E8-11 (SG-1) Below 1 ohms B5-2 - E8-5 (TAM) Below 1 ohms B5-1 - Body ground 10 kohms or higher B5-2 - Body ground 10 kohms or higher Reconnect the ambient temperature sensor connector. Reconnect the air conditioning amplifier connector. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (Scheme 9): Identifying B5 Ambient Temperature Sensor Connector Terminals OK: REPLACE AIR CONDITIONING AMPLIFIER

The No. 1 cooler thermistor (evaporator temperature sensor) is installed on the evaporator in the air conditioner unit to detect the temperature of the cooled air that has passed through the evaporator and to control the air conditioner. It sends signals to the air conditioning amplifier, which change in accordance with the resistance of the No. 1 cooler thermistor (evaporator temperature sensor). As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases. The air conditioning amplifier applies a voltage (5V) to the No. 1 cooler thermistor (evaporator temperature sensor) and reads voltage changes as changes in the resistance of the evaporator temperature sensor. This sensor is used for frost prevention.

DTC DETECTION CONDITION AND TROUBLE AREA REFERENCE

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1. READ VALUE USING INTELLIGENT TESTER (EVAP FIN TEMP) Connect the intelligent tester with CAN VIM to the DLC3. Turn the ignition switch ON and turn the intelligent tester main switch ON. Select the item below in the DATA LIST, and read the value displayed on the intelligent tester. DATA LIST / AIR CONDITIONER DIAGNOSTIC NOTE AND MEASUREMENT ITEM / DISPLAY RANGE Item Measurement Item / Display (Range) Normal Condition Diagnostic Note EVAP FIN TEMP (Evaporator fin thermistor) Evaporator fin thermistor / Min.:-29.7°C(-21.46°F) Max.: 59.55°C (139.019°F) Actual evaporator temperature is displayed Open circuit: -29.7°C (-21.46°F) Short circuit: 59.55°C (139.019°F) OK: The display is as specified in the normal condition column. Result RESULT REFERENCE Result Proceed to NG A OK (Checking from the «PROBLEM SYMPTOMS TABLE»(ref-267417-S35547163962007101100000) ) B OK (Checking from the DTC) C B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN «PROBLEM SYMPTOMS TABLE»(ref-267417-S35547163962007101100000) C: REPLACE AIR CONDITIONING AMPLIFIER A: GO TO NEXT STEP
2. INSPECT NO. 1 COOLER THERMISTOR (EVAPORATOR TEMPERATURE SENSOR) Remove the evaporator temperature sensor. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION 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: Touching the sensor even slightly 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 on the left). Reinstall the evaporator temperature sensor. NG: REPLACE NO. 1 COOLER THERMISTOR (EVAPORATOR TEMPERATURE SENSOR) (Scheme 11): Identifying No. 1 Cooler Thermistor And Temperature Graph OK: GO TO NEXT STEP
3. CHECK HARNESS AND CONNECTOR (No. 1 COOLER THERMISTOR - AIR CONDITIONING AMPLIFIER) Disconnect the E2 No. 1 cooler thermistor (evaporator temperature sensor) connector. Disconnect the E8 air conditioning amplifier connector. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition E2-2-E8-10(TE) Below 1 ohms E2-1 - E8-4 (SG-2) Below 1 ohms E2-2 - Body ground 10 kohms or higher E2-1 - Body ground 10 kohms or higher Reconnect the No. 1 cooler thermistor connector. Reconnect the air conditioning amplifier connector. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (Scheme 12): Identifying E2 No. 1 Cooler Thermistor OK: REPLACE AIR CONDITIONING AMPLIFIER

This DTC is output when the refrigerant pressure is either 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, detects the refrigerant pressure and sends a refrigerant pressure signal to the air conditioning amplifier. The air conditioning amplifier determines the pressure from the signals in accordance with the sensor characteristics, and controls the compressor.

DTC DETECTION CONDITION AND TROUBLE AREA REFERENCE

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1. CHECK REFRIGERANT Check the sight glass of the cooler unit refrigerant liquid pipe. Prepare the vehicle in accordance with the chart below. INSPECTION PROCEDURE CHART Item Condition Vehicle Doors Fully open Temperature Setting MAX COLD Blower Speed HI A/C Switch ON Compare the sight glass to the following chart. (Scheme 14): Identifying Cooler Unit Refrigerant Liquid Pipe Sight Glass SIGHT GLASS DIAGNOSIS CHART Item Symptom Amount of Refrigerant Corrective Procedures 1 Bubbles visible Insufficient* Check for gas leakage and repair if necessary Add refrigerant until bubbles disappear 2 No bubbles visible Empty, insufficient or too much Refer to items 3 and 4 3 No temperature difference between compressor inlet and outlet Empty or nearly empty Check for gas leakage with gas leak detector and repair if necessary Add refrigerant until bubbles disappear 4 Considerable temperature difference between compressor inlet and outlet Correct or too much Refer to items 5 and 6 5 Immediately after A/C turned OFF, refrigerant becomes clear Too much Drain or discharge refrigerant Bleed air and supply proper amount of purified refrigerant 6 Immediately after A/C turned OFF, refrigerant foams and then becomes clear Correct - HINT: *: If the ambient temperature is higher than usual but cooling is sufficient, bubbles in the sight glass are permissible. NG: CHARGE REFRIGERANT OK: GO TO NEXT STEP
2. READ VALUE OF INTELLIGENT TESTER (REG PRESS SENS) Connect the intelligent tester to the DLC3. Turn the ignition switch ON and turn the intelligent tester main switch ON. Select the item below in the DATA LIST, and read the value displayed on the intelligent tester. DATA LIST/ AIR CONDITIONER DATA LIST - AIR CONDITIONER Item Measure Item / Display (Range) Normal Condition Diagnostic Note REG PRESS SENS (Regulator pressure sensor) Regulator Pressure Sensor/ Min.: 0kgf/cm 2 G, Max.: 38.25 kgf/ cm 2G Actual regulator pressure is displayed - OK: The display is as specified in the normal condition column. Result RESULT REFERENCE Result Proceed to NG A OK (Checking from the «PROBLEM SYMPTOMS TABLE»(ref-267417-S35547163962007101100000) ) B OK (Checking from the DTC) C B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN «PROBLEM SYMPTOMS TABLE»(ref-267417-S35547163962007101100000) C: REPLACE AIR CONDITIONING AMPLIFIER A: GO TO NEXT STEP
3. CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - AIR CONDITIONING AMPLIFIER) Disconnect the A3 air conditioning pressure sensor connector. Disconnect the E8 air conditioning amplifier connector. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition A3-1(-)-E8-11 (SG-1) Below 1 ohms A3-2 (PR) - E8-6 (PRE) Below 1ohms A3-3 (+) - E8-1 (S5-3) Below 1 ohms A3-1 (-) - Body ground 10 kohms or higher A3-2 (PR) - Body ground 10 kohms or higher A3-3 (+) - Body ground 10 kohms or higher Reconnect the air conditioning pressure sensor connector. Reconnect the air conditioning amplifier connector. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (Scheme 15): Identifying A3 Air Conditioning Pressure Sensor Connector Terminals OK: GO TO NEXT STEP
4. INSPECT AIR CONDITIONING AMPLIFIER Remove the air conditioning amplifier with its connectors still connected. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition E8-11 (SG-1)-E8-12 (GND) Below 1 ohms Turn the ignition switch ON. Measure the voltage. Standard voltage TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition E8-1(S5-3)-E8-11(SG-1) 4.5 to 5.5 V Reinstall the air conditioning amplifier. NG: REPLACE AIR CONDITIONING AMPLIFIER (Scheme 16): Identifying Air Conditioning Amplifier Connector Terminals OK: GO TO NEXT STEP
5. INSPECT AIR CONDITIONING PRESSURE SENSOR Remove the air conditioning amplifier with its connectors still connected. Set the manifold gauge. Warm up the engine. Turn the A/C switch ON. Measure the voltage. Standard voltage TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Refrigerant Pressure Specified Condition E8-6(PRE)-E8-11 (SG-1) 0.196 to 3.14 MPa (2.0 to 32 kgf/cm 2 ) 0.76 to 4.74 V Reinstall the air conditioning amplifier. NG: REPLACE LIQUID TUBE SUB-ASSEMBLY A (AIR CONDITIONING PRESSURE SENSOR) (Scheme 17): Identifying E8 Air Conditioning Amplifier Connector Terminals OK: REPLACE AIR CONDITIONING AMPLIFIER

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

Based on this signal, the compressor changes the degree of refrigerant compression.

DTC DETECTION CONDITION AND TROUBLE AREA REFERENCE

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1. READ VALUE OF INTELLIGENT TESTER (REG CTRL CURRNT) Connect the intelligent tester with CAN VIM to the DLC3. Turn the ignition switch ON and turn the intelligent tester main switch ON. Select the items below in the DATA LIST, and read the value displayed on the intelligent tester. DATA LIST / AIR CONDITIONER DIAGNOSTIC NOTE AND MEASUREMENT ITEM / DISPLAY RANGE ITEM Measurement Item / Display Normal Condition Diagnostic Note REG CTRL CURRNT (Regulator control current) Regulator control current / Min.: 0A Max.: 0.997 A Value changes between 0 A and 0.997 A in accordance with compressor and pulley operation - OK: The display is as specified in the normal condition column. Result RESULT REFERENCE Result Proceed to NG A OK (Checking from the «PROBLEM SYMPTOMS TABLE»(ref-267417-S35547163962007101100000) ) B OK (Checking from the DTC) c B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN «PROBLEM SYMPTOMS TABLE»(ref-267417-S35547163962007101100000) C: REPLACE AIR CONDITIONING AMPLIFIER A: GO TO NEXT STEP
2. INSPECT COMPRESSOR AND PULLEY Disconnect the C8 compressor and pulley connector. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition C8-1 - C8-2 10.1 to 11.1 ohms at 25°C (77°F) Reconnect the compressor and pulley connector. NG: REPLACE COMPRESSOR AND PULLEY (Scheme 19): Identifying Compressor And Pulley Connector Terminals OK: GO TO NEXT STEP
3. CHECK HARNESS AND CONNECTOR (COMPRESSOR AND PULLEY - AIR CONDITIONING AMPLIFIER) Disconnect the C8 compressor and pulley connector. Disconnect the E8 air conditioning amplifier connector. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition C8-1 - E8-7 (SOL+) Below 1 ohms C8-1 - Body ground 10 kohms or higher Reconnect the compressor and pulley connector. Reconnect the air conditioning amplifier connector. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (Scheme 20): Identifying C8 Compressor And Pulley Connector Terminals OK: GO TO NEXT STEP
4. CHECK HARNESS AND CONNECTOR (COMPRESSOR AND PULLEY - BODY GROUND) Disconnect the C8 compressor and pulley connector. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition C8-2 - Body ground Below 1 ohms Reconnect the compressor and pulley connector. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (Scheme 21): Identifying C8 Compressor And Pulley Connector Terminals OK: REPLACE AIR CONDITIONING AMPLIFIER

The air conditioning amplifier communicates data with the ECM and combination meter assembly through the CAN communication system.

DTC DETECTION CONDITION AND TROUBLE AREA REFERENCE

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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 FUSE (GAUGE, HTR) Remove the GAUGE fuse from the main body ECU. Remove the HTR fuse from the engine room relay block. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Item Specified Condition GAUGE fuse Below 1 ohms HTR fuse Below 1 ohms Reinstall the GAUGE fuse. Reinstall the HTR fuse. NG: REPLACE FUSE OK: GO TO NEXT STEP
2. INSPECT HTR RELAY Remove the HTR relay from the main body ECU. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition 3-4 Below 1 ohms 3-5 10 kohms or higher 3-4 10 kohms or higher (when battery voltage is applied to terminals 1 and 2) 3-5 Below 1 ohms (when battery voltage is applied to terminals 1 and 2) Reinstall the HTR relay. NG: REPLACE HTR RELAY (Scheme 24): Inspecting HTR Relay OK: GO TO NEXT STEP
3. INSPECT BLOWER MOTOR Disconnect the E4 blower motor connector. Connect the positive (+) lead from the battery to terminal 2 and the negative (-) lead to terminal 1, then check that the blower motor operates smoothly. OK: The blower motor operates smoothly. Measure the current. Standard current TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition E4-2 (+B) - E4-1 (GND) 1 to 3A Reconnect the blower motor connector. NG: REPLACE BLOWER MOTOR (Scheme 25): Inspecting Blower Motor 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. Standard voltage TESTER CONNECTION AND SPECIFIED CONDITION 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 (Scheme 26): Identifying 4L Main Body ECU Connector Terminals OK: GO TO NEXT STEP
5. CHECK MAIN BODY ECU Remove the HTR relay from the main body ECU. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition 4F-7 - HTR-3 Below 1 ohms 4E-17-HTR-4 Below 1 ohms Measure the voltage. Standard voltage TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Condition Specified Condition HTR-5 - Body ground Always 11 to 14 V Reinstall the HTR relay. Measure the voltage. Standard voltage TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Condition Specified Condition 4Q-5 - Body ground Ignition switch ON 11 to 14 V NG: REPLACE MAIN BODY ECU (Scheme 27): Identifying HTR Relay Terminals OK: GO TO NEXT STEP
6. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - HEATER CONTROL (BLOWER SWITCH)) Disconnect the E1 heater control (blower switch) connector. Measure the voltage. Standard voltage TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Condition Specified Condition E1-9(LO)-Body ground Ignition switch ON 11 to 14 V Reconnect the heater control (blower switch) connector. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (Scheme 28): Identifying E1 Heater Control (Blower Switch) Connector Terminals OK: GO TO NEXT STEP
7. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - BLOWER MOTOR) Disconnect the E4 blower motor connector. Measure the voltage. Standard voltage TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Condition Specified Condition E4-1 (+B) - Body ground Ignition switch ON 11 to 14 V Reconnect the blower motor connector. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (Scheme 29): Identifying E4 Blower Motor Connector Terminals OK: GO TO NEXT STEP
8. CHECK HARNESS AND CONNECTOR (BLOWER RESISTOR - BLOWER MOTOR) Disconnect the E3 blower resistor connector. Disconnect the E4 blower motor connector. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition E3-4 - E4-1 Below 1 ohms Reconnect the blower resistor connector. Reconnect the blower motor connector. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (Scheme 30): Identifying E3 Blower Resistor Connector Terminals OK: GO TO NEXT STEP
9. INSPECT BLOWER RESISTOR Remove the blower resistor. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition 4-1 3.12 to 3.60ohms 4-3 1.45 to 1.67ohms 4-2 0.52 to 0.60ohms Reinstall the blower resistor. NG: REPLACE BLOWER RESISTOR (Scheme 31): Identifying E4 Blower Motor Connector Terminals OK: GO TO NEXT STEP
10. INSPECT HEATER CONTROL (BLOWER SWITCH) Remove the heater control (blower switch). Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Switch Position Tester Connection Specified Condition 0 ALL - 5 (E) 10 kohms or higher 1 9 (LO) - 5 (E) Below 1 ohms 1-2 9(LO)-5(E)-7(M1) Below 1 ohms 2 9(LO)-5(E)-7(M1) Below 1 ohms 2-3 9(LO)-5(E)-7(M1)-6 (M2) Below 1 ohms 3 9 (LO) - 5 (E) - 6 (M2) Below 1 ohms 3-4 9 (LO) - 5 (E) - 6 (M2) -10 (HI) Below 1 ohms 4 9(LO)-5(E)-10(HI) Below 1 ohms Reinstall the heater control (blower switch). NG: REPLACE HEATER CONTROL (Scheme 32): Identifying Heater Control (Blower Switch) Terminals OK: GO TO NEXT STEP
11. CHECK HARNESS AND CONNECTOR (HEATER CONTROL (BLOWER SWITCH) BLOWER RESISTOR) Disconnect the E1 heater control (blower switch) connector. Disconnect the E3 blower resistor connector. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition E1-5(E)-E3-1 Below 1 ohms E1-6(M2)-E3-2 Below 1 ohms E1-7(M1)-E3-3 Below 1 ohms E1-10(HI)-E3-4 Below 1 ohms Reconnect the heater control (blower switch) connector. Reconnect the blower resistor connector. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (Scheme 33): Identifying E1 Heater Control (Blower Switch) Connector Terminals OK: REPAIR OR REPLACE HARNESS OR CONNECTOR (BLOWER RESISTOR - BODY GROUND)

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 FUSE (A/C, HTR SUB1, HTR SUB2) Remove the A/C fuse from the main body ECU. Remove the HTR SUB1 and HTR SUB2 fuses from the engine room relay block. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Item Specified Condition A/C fuse Below 1 ohms HTR SUB 1 fuse Below 1 ohms HTR SUB 2 fuse Below 1 ohms Reinstall the A/C fuse. Reinstall the HTR SUB1 and HTR SUB2 fuses. NG: REPLACE FUSE OK: GO TO NEXT STEP
2. INSPECT NO. 3 HEATER CONTROL KNOB Remove the No. 3 heater control knob. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Condition Specified Condition 3 (IG+) - 6 (B) Max hot position Below 1 ohms 3 (IG+) - 6 (B) Other than max hot position 10 kohms or higher Reinstall the No. 3 heater control knob. NG: REPLACE NO. 3 HEATER CONTROL KNOB (Scheme 35): Identifying No. 3 Heater Control Knob OK: GO TO NEXT STEP
3. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - AIR CONDITIONING AMPLIFIER) Disconnect the E6 No. 3 heater control knob connector. Measure the voltage. Standard voltage TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Condition Specified Condition E6-3 (IG+) - Body ground Ignition switch ON 11 to 14 V Reconnect the No. 3 heater control knob connector. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (Scheme 36): Identifying No. 3 Heater Control Knob Connector Terminals OK: GO TO NEXT STEP
4. CHECK HARNESS AND CONNECTOR (No. 3 HEATER CONTROL KNOB - AIR CONDITIONING AMPLIFIER) Disconnect the E6 No. 3 heater control knob connector. Disconnect the E9 air conditioning amplifier connector. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition E6-6 (B) - E9-14 (HEAT) Below 1 ohms Reconnect the No. 3 heater control knob connector. Reconnect the air conditioning amplifier connector. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (Scheme 37): Identifying E6 No. 3 Heater Control Knob Connector Terminals OK: GO TO NEXT STEP
5. INSPECT AIR CONDITIONING AMPLIFIER Remove the air conditioning amplifier with its connectors still connected. Turn the ignition switch ON. When the PTC heater operating conditions are met (engine at idling speed or faster, ambient temperature is 10°C (50°F) or less, engine coolant temperature is 65°C (149°F) or less, and No. 3 heater control knob setting is MAX HOT), turn the blower switch to the Lo setting. Wait 30 seconds. Measure the voltage. Standard voltage TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition E9-9 (PTC1) - Body ground 11 to 14 V E9-10 (PTC2) - Body ground 11 to 14 V E9-12 (PTC3) - Body ground 11 to 14 V Reinstall the air conditioning amplifier. (Scheme 38): Identifying Air Conditioning Amplifier Connector Terminals NG: REPLACE AIR CONDITIONING AMPLIFIER OK: GO TO NEXT STEP
6. INSPECT PTC HEATER RELAY (HTR SUB1, HTR SUB2, HTR SUB3) Remove the HTR SUB1 relay from the engine room relay block. Remove the HTR SUB2 and HTR SUB3 relays from the engine room sub relay block. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition 3-5 10 kohms or higher 3-5 Below 1 ohms (when battery voltage is applied to terminals 1 and 2) (Scheme 39): Inspecting PTC Heater Relay (HTR SUB1, HTR SUB2, HTR SUB3) Reinstall the HTR SUB1 relay. Reinstall the HTR SUB2 and HTR SUB3 relays. NG: REPLACE PTC HEATER RELAY OK: GO TO NEXT STEP
7. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - PTC HEATER RELAY) Remove the HTR SUB1 relay from the engine room R/B. Remove the HTR SUB2 and HTR SUB3 relays from the engine room R/B No. 2. Turn the ignition switch ON. When the PTC heater operating conditions are met (engine at idling speed or faster, ambient temperature is 10°C (50°F) or less, engine coolant temperature is 65°C (149°F) or less, and No. 3 heater control knob setting is MAX HOT), turn the blower switch to the Lo setting. Wait 30 seconds. Measure the voltage. Standard voltage. TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition HTR SUB1-2 - Body ground 11 to 14V HTR SUB2-2 - Body ground 11 to 14V HTR SUB3-2 - Body ground 11 to 14V Reinstall the HTR SUB1 relay. Reinstall the HTR SUB2 and HTR SUB3 relays. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: GO TO NEXT STEP (Scheme 40): Identifying HTR SUB2 And HTR SUB3 Relays
8. CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - BODY GROUND) Remove the HTR SUB1 relay from the engine room R/B. Remove the HTR SUB2 and HTR SUB3 relays from the engine room R/B No. 2. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition HTR SUB1-1 - Body ground Below 1 ohms HTR SUB2-1 - Body ground Below 1 ohms HTR SUB3-1 - Body ground Below 1 ohms Reinstall the HTR SUB1 relay. Reinstall the HTR SUB2 and HTR SUB3 relays. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (Scheme 41): Identifying HTR SUB2 And HTR SUB3 Relays OK: GO TO NEXT STEP
9. INSPECT PTC HEATER ASSEMBLY Disconnect the A17 PTC heater assembly connector. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition 1-2 Below 1 ohms 1-3 Below 1 ohms 2-3 Below 1 ohms Reconnect the PTC heater assembly connector. NG: REPLACE PTC HEATER ASSEMBLY (Scheme 42): Identifying PTC Heater Assembly Connector Terminals OK: GO TO NEXT STEP
10. CHECK HARNESS AND CONNECTOR (BATTERY - PTC HEATER RELAY) Remove the HTR SUB1 relay from the engine room R/B. Remove the HTR SUB2 and HTR SUB3 relays from the engine room R/B No. 2. Measure the voltage. Standard voltage TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Condition Specified Condition HTR SUB1-5-Body ground Always 11 to 14 V HTR SUB2-5 - Body ground Always 11 to 14 V HTR SUB3-5 - Body ground Always 11 to 14 V Reinstall the HTR SUB1 relay. Reinstall the HTR SUB2 and HTR SUB3 relays. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR see scheme 56: Identifying HTR SUB2 And HTR SUB3 Relays OK: GO TO NEXT STEP
11. CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - PTC HEATER ASSEMBLY) Remove the HTR SUB1 relay from the engine room R/B. Remove the HTR SUB2 and HTR SUB3 relays from the engine room R/B No. 2. Disconnect the A17 PTC heater assembly connector. Measure the resistance. Standard resistance TESTER CONNECTION AND SPECIFIED CONDITION Tester Connection Specified Condition HTRSUB1-3-A17-2(B) Below 1 ohms HTRSUB2-3-A17-3(B) Below 1 ohms HTRSUB3-3-A17-1(B) Below 1 ohms Reinstall the HTR SUB1 relay. Reinstall the HTR SUB2 and HTR SUB3 relays. Reconnect the PTC heater assembly connector. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (Scheme 43): Identifying HTR SUB2 And HTR SUB3 Relays OK: REPLACE AIR CONDITIONING AMPLIFIER

This is the main power source supplied to the air conditioning amplifier when the ignition switch is turned on. This power source is used for operating components such as the air conditioning amplifier.

Scheme 45

See also:
• PRECAUTION
• REMOVAL