Air Conditioning System (Diagnostic Codes & Circuit Tests) (Base): Overview Toyota Prius Plug-in

DESCRIPTION

The room temperature sensor is installed in the instrument panel. It detects the cabin temperature to control the air conditioning AUTO mode. The resistance of the room temperature sensor changes in accordance with the cabin temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The A/C amplifier applies voltage (5 V) to the room temperature sensor and reads voltage changes as the resistance of the room temperature sensor changes. This sensor also sends appropriate signals to the A/C amplifier. The room temperature sensor is integrated with the room humidity sensor.

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1. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the power switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Air Conditioner / Data List. Check the value(s) by referring to the table below. AIR CONDITIONER Tester Display Measurement Item/Range Normal Condition Diagnostic Note Room Temperature Sensor Room temperature sensor / Min.: -6.5°C (20.3°F) Max.: 57.25°C (135.05°F) Actual cabin temperature displayed - OK The display is as specified in the Normal Condition column. Result Result Proceed to NG A OK (When troubleshooting according to Problem Symptoms Table) B OK (When troubleshooting according to the DTC) C B --> See step 4 C --> See step 5 A: Go to next step
2. INSPECT ROOM TEMPERATURE SENSOR Remove the room temperature sensor. Disconnect the room temperature sensor connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition L44-1 - L44-2 10°C (50°F) 3.00 to 3.73 kohms L44-1 - L44-2 15°C (59°F) 2.45 to 2.88 kohms L44-1 - L44-2 20°C (68°F) 1.95 to 2.30 kohms L44-1 - L44-2 25°C (77°F) 1.60 to 1.80 kohms L44-1 - L44-2 30°C (86°F) 1.28 to 1.47 kohms L44-1 - L44-2 35°C (95°F) 1.00 to 1.22 kohms L44-1 - L44-2 40°C (104°F) 0.80 to 1.00 kohms L44-1 - L44-2 45°C (113°F) 0.65 to 0.85 kohms L44-1 - L44-2 50°C (122°F) 0.50 to 0.70 kohms L44-1 - L44-2 55°C (131°F) 0.44 to 0.60 kohms L44-1 - L44-2 60°C (140°F) 0.36 to 0.50 kohms NOTE: Hold the sensor only by its connector. Touching the sensor may change the resistance value. When measuring, the sensor temperature must be the same as the ambient temperature. HINT: As the temperature increases, the resistance decreases (see the graph (Scheme 83) ). TEXT IN ILLUSTRATION *1 Component without harness connected (Room Temperature Sensor) *2 Sensing Portion NG --> See step 6 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (ROOM TEMPERATURE SENSOR - A/C AMPLIFIER) Disconnect the A/C amplifier connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition L17-29 (TR) - L44-1 Always Below 1 ohms L17-34 (SG-1) - L44-2 Always Below 1 ohms L17-29 (TR) - Body ground Always 10 kohms or higher L17-34 (SG-1) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to Room Temperature Sensor) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 5
4. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-551393-S01699272352013051500000)
5. REPLACE A/C AMPLIFIER. Refer to «REMOVAL»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base)
6. REPLACE ROOM TEMPERATURE SENSOR. Refer to «REMOVAL»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base)

The ambient temperature sensor is installed in front of the condenser. It detects the ambient temperature to control air conditioning AUTO mode. This sensor is connected to the A/C amplifier and detects fluctuations in the ambient temperature. This data is used for controlling the cabin temperature. The sensor sends a signal to the A/C 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 A/C amplifier applies voltage (5 V) to the ambient temperature sensor and reads voltage changes as the resistance of the ambient temperature sensor changes.

Scheme 86

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1. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the power switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Air Conditioner / Data List. Check the value(s) by referring to the table below. AIR CONDITIONER Tester Display Measurement Item/Range Normal Condition Diagnostic Note Ambient Temp Sensor Ambient temperature sensor / Min: -23.3°C (-9.94°F) Max: 65.95°C (150.71°F) Actual ambient temperature displayed - OK The display is as specified in the Normal Condition column. Result Result Proceed to NG A OK (When troubleshooting according to Problem Symptoms Table) B OK (When troubleshooting according to the DTC) C B --> See step 4 C --> See step 5 A: Go to next step
2. INSPECT AMBIENT TEMPERATURE SENSOR Remove the ambient temperature sensor. Disconnect the ambient temperature sensor connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A4-1 - A4-2 10°C (50°F) 3.00 to 3.73 kohms A4-1 - A4-2 15°C (59°F) 2.45 to 2.88 kohms A4-1 - A4-2 20°C (68°F) 1.95 to 2.30 kohms A4-1 - A4-2 25°C (77°F) 1.60 to 1.80 kohms A4-1 - A4-2 30°C (86°F) 1.28 to 1.47 kohms A4-1 - A4-2 35°C (95°F) 1.00 to 1.22 kohms A4-1 - A4-2 40°C (104°F) 0.80 to 1.00 kohms A4-1 - A4-2 45°C (113°F) 0.65 to 0.85 kohms A4-1 - A4-2 50°C (122°F) 0.50 to 0.70 kohms A4-1 - A4-2 55°C (131°F) 0.44 to 0.60 kohms A4-1 - A4-2 60°C (140°F) 0.36 to 0.50 kohms NOTE: Hold the sensor only by its connector. Touching the sensor may change the resistance value. When measuring, the sensor temperature must be the same as the ambient temperature. HINT: As the temperature increases, the resistance decreases (see the graph (Scheme 87) ). TEXT IN ILLUSTRATION *1 Component without harness connected (Ambient Temperature Sensor) *2 Sensing Portion NG --> See step 6 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (AMBIENT TEMPERATURE SENSOR - A/C AMPLIFIER) Disconnect the A/C amplifier connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition L17-5 (TAM) - A4-1 Always Below 1 ohms L17-13 (SG-2) - A4-2 Always Below 1 ohms L17-5 (TAM) - Body ground Always 10 kohms or higher L17-13 (SG-2) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to Ambient Temperature Sensor) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 5
4. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-551393-S01699272352013051500000)
5. REPLACE A/C AMPLIFIER. Refer to «REMOVAL»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base)
6. REPLACE AMBIENT TEMPERATURE SENSOR. Refer to «REMOVAL»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base)

The evaporator temperature sensor is installed on the evaporator in the air conditioning unit to detect the cooled air temperature that has passed through the evaporator and to control the air conditioning. It sends appropriate signals to the A/C amplifier. The resistance of the evaporator temperature sensor changes in accordance with the cooled air temperature 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 and reads voltage changes as the resistance of the evaporator temperature sensor changes. This sensor is used for frost prevention.

Scheme 90

Scheme 91

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Scheme 93

1. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the power switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Air Conditioner / Data List. Check the value(s) by referring to the table below. AIR CONDITIONER Tester Display Measurement Item/Range Normal Condition Diagnostic Note Evaporator Fin Thermistor Evaporator temperature sensor / Min.: -29.7°C (-21.46°F) Max.: 59.55°C (139.19°F) Actual evaporator temperature displayed - OK The display is as specified in the Normal Condition column. Result Result Proceed to NG A OK (When troubleshooting according to Problem Symptoms Table) B OK (When troubleshooting according to the DTC) C B --> See step 5 C --> See step 4 A: Go to next step
2. INSPECT EVAPORATOR TEMPERATURE SENSOR Remove the evaporator temperature sensor. Disconnect the evaporator temperature sensor connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition z21-1 - z21-2 -10°C (14°F) 7.30 to 9.10 kohms z21-1 - z21-2 -5°C (23°F) 5.65 to 6.95 kohms z21-1 - z21-2 0°C (32°F) 4.40 to 5.35 kohms z21-1 - z21-2 5°C (41°F) 3.40 to 4.15 kohms z21-1 - z21-2 10°C (50°F) 2.70 to 3.25 kohms z21-1 - z21-2 15°C (59°F) 2.14 to 2.58 kohms z21-1 - z21-2 20°C (68°F) 1.71 to 2.05 kohms z21-1 - z21-2 25°C (77°F) 1.38 to 1.64 kohms z21-1 - z21-2 30°C (86°F) 1.11 to 1.32 kohms NOTE: Hold the sensor only by its connector. Touching the sensor may change the resistance value. When measuring, the sensor temperature must be the same as the ambient temperature. HINT: As the temperature increases, the resistance decreases (see the graph (Scheme 91) ). TEXT IN ILLUSTRATION *1 Component without harness connected (Evaporator Temperature Sensor) *2 Sensing Portion NG --> See step 7 OK: Go to next step
3. INSPECT AIR CONDITIONING HARNESS (A/C AMPLIFIER - EVAPORATOR TEMPERATURE SENSOR) Remove the air conditioning harness. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition z11-6 (TEA) - z21-2 Always Below 1 ohms z11-5 (SGA) - z21-1 Always Below 1 ohms z11-6 (TEA) - Body ground Always 10 kohms or higher z11-5 (SGA) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to Evaporator Temperature Sensor) NG --> See step 8 OK --> See step 6
4. REPLACE A/C AMPLIFIER. Refer to «REMOVAL»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base)
5. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-551393-S01699272352013051500000)
6. REPLACE A/C AMPLIFIER. Refer to «REMOVAL»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base)
7. REPLACE EVAPORATOR TEMPERATURE SENSOR. Refer to «REMOVAL»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base)
8. REPLACE AIR CONDITIONING HARNESS. Refer to «DISASSEMBLY»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base)

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

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1. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) Disconnect the 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 A31-3 (+) - Body ground Power switch on (IG) 4.75 to 5.25 V TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Pressure Sensor) NG --> See step 5 OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A31-1 (-) - Body ground Always Below 1 ohms TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Pressure Sensor) NG --> See step 6 OK: Go to next step
3. INSPECT A/C PRESSURE SENSOR (SENSOR SIGNAL CIRCUIT) Reconnect the A/C pressure sensor connector. Remove the A/C amplifier with the connectors still connected. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition L17-9 (PRE) - Body ground Power switch on (IG) (A/C: off) 0.73 to 4.84 V HINT: If the voltage is not as specified, there may be a malfunction in the A/C amplifier, A/C pressure sensor or wire harness. It is also possible that the amount of refrigerant may not be appropriate. TEXT IN ILLUSTRATION *1 Component with harness connected (A/C Amplifier) 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) NOTE: If refrigerant pressure on the high pressure line becomes extremely high during the inspection (if the voltage exceeds 4.84 V), the fail-safe function stops compressor operation. Therefore, measure the voltage before the fail-safe function operates. It is necessary to measure the voltage over a period 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 signals from the ambient temperature sensor and 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 L17-9 (PRE) - Body ground Power switch on (IG) (A/C: on) 0.73 to 4.84 V Result Result Proceed to OK (When troubleshooting according to the DTC) A OK (When troubleshooting according to Problem Symptoms Table) B NG C TEXT IN ILLUSTRATION *1 Component with harness connected (A/C Amplifier) B --> See step 21 C --> See step 13 A --> See step 22
5. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - A/C PRESSURE SENSOR) Disconnect the A/C amplifier connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A31-3 (+) - L17-10 (S5-3) Always Below 1 ohms L17-10 (S5-3) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to A/C Pressure Sensor) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 22
6. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - A/C PRESSURE SENSOR) Disconnect the A/C amplifier connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A31-1 (-) - L17-13 (SG-2) Always Below 1 ohms L17-13 (SG-2) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to A/C Pressure Sensor) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 22
7. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - A/C PRESSURE SENSOR) Disconnect the A/C amplifier connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A31-2 (PR) - L17-9 (PRE) Always Below 1 ohms L17-9 (PRE) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to A/C Pressure Sensor) 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. OK Vacuum can be maintained in the A/C system. HINT: If vacuum cannot be maintained in the A/C system, there may be a refrigerant leak. In this case, it is necessary to repair or replace the leaking part of the A/C system. NG --> See step 12 OK: Go to next step
9. CHARGE REFRIGERANT Add an appropriate amount of refrigerant. Refer to «REPLACEMENT - Step 2»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base) . NEXT: Go to next step
10. RECHECK FOR 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) NOTE: If refrigerant pressure on the high pressure line is excessive, this DTC will be set. Therefore, it is necessary to measure the voltage over a period of time (approximately 10 minutes) because this DTC may be set after the A/C has been operating for a while. HINT: When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to signals from 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 B1423/23 is output A DTC B1423/23 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 any refrigerant leaks as necessary. B --> END A: Go to next step
11. INSPECT A/C PRESSURE SENSOR Install the manifold gauge set. Reconnect the A/C pressure sensor connector. Turn the power switch on (IG). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition L17-9 (PRE) - L17-13 (SG-2) Refrigerant pressure: Normal pressure (less than 3.187 MPa [462 psi] and more than 0.39 MPa [57 psi]) 1.0 to 4.912 V TEXT IN ILLUSTRATION *1 Component with harness connected (A/C Amplifier) NG --> See step 19 OK --> See step 22
12. REPAIR A/C SYSTEM LEAK Identify the area where refrigerant leaks from. Refer to «REPLACEMENT - Step 4»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base) . Repair the identified area of the A/C system. Evacuate the A/C system. NEXT --> See step 23
13. INSPECT COOLING FAN SYSTEM Check that the cooling fan(s) operates normally. HINT: Refer to Cooling Fan Circuit. Refer to «Cooling Fan Circuit»(ref-551549-S38320198362013051500000). 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 «REPLACEMENT - Step 2»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base) . 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, recover the refrigerant and properly evacuate the system. Add an appropriate amount of refrigerant, and check for DTCs. NEXT: Go to next step
15. RECHECK FOR 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) NOTE: If refrigerant pressure on the high pressure line is excessive, this DTC will be set. Therefore, it is necessary to measure the voltage over a period of time (approximately 10 minutes) because DTC may be set after the A/C has been operating for a while. HINT: When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to signals from 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, recover the refrigerant and properly evacuate the system. Add an appropriate amount of refrigerant, and check for the DTC. If the DTC is not output, it indicates that the cooler dryer in the condenser is not able to absorb moisture in the refrigerant. In this case, to complete the repair, it is necessary to replace the cooler dryer. Result Result Proceed to DTC B1423/23 is output A DTC B1423/23 is not output B B --> See step 25 A: Go to next step
16. REPLACE EXPANSION VALVE Replace the expansion valve with a new or a known good one. Refer to «DISASSEMBLY»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base) . HINT: Replace the expansion valve with a new or a known good 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 «REPLACEMENT - Step 2»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base) . NEXT: Go to next step
18. RECHECK FOR 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) NOTE: If refrigerant pressure on the high pressure line is excessive, this DTC will be set. Therefore, it is necessary to measure the voltage over a period of time (approximately 10 minutes) because this DTC may be set after the A/C has been operating for a while. HINT: When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to signals from the ambient temperature sensor and evaporator temperature sensor to prevent the evaporator from freezing. In this case, perform the inspection in a warm indoor environment. If refrigerant pressure is not normal after replacing the expansion valve with a new or a known good one, the condenser or pipes may be clogged with dirt, dust or other contaminants. In this case, clean or replace the condenser or pipes. Result Result Proceed to DTC B1423/23 is not output A DTC B1423/23 is output B B --> See step 24 A --> END
19. REPLACE A/C PRESSURE SENSOR Replace the A/C pressure sensor. Refer to «REMOVAL»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base) . HINT: Since the A/C pressure sensor cannot be inspected while it is removed from the vehicle, replace the A/C pressure sensor with a new or a known good one and check that the condition returns to normal. NEXT: Go to next step
20. RECHECK FOR 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) NOTE: If refrigerant pressure on the high pressure line is excessive, this DTC will be set. Therefore, it is necessary to measure the voltage over a period of time (approximately 10 minutes) because this DTC may be set after the A/C has been operating for a while. HINT: When the outside air temperature is low (below -1.5°C (29.3°F)), the compressor stops due to signals from the ambient temperature sensor and 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 B1423/23 is not output A DTC B1423/23 is output B B --> See step 22 A --> END
21. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-551393-S01699272352013051500000)
22. REPLACE A/C AMPLIFIER. Refer to «REMOVAL»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base)
23. CHARGE REFRIGERANT. Refer to «REPLACEMENT - Step 2»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base)
24. REPLACE CONDENSER. Refer to «REMOVAL»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base)
25. REPLACE COOLER DRYER. Refer to «DISASSEMBLY»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base)

The air mix control servo motor sends pulse signals to indicate the damper position to the A/C amplifier. The A/C amplifier activates the motor (normal or reverse) based on these signals to move the air mix damper to any position. As a result, the amount of air passing through the heater core after passing through the evaporator is adjusted, and the temperature of the air blowing toward the passenger side is controlled.

The A/C amplifier communicates with the servo through a communication/driver IC and wiring assembly called the air conditioning harness.

HINT

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

Scheme 105

The air inlet control servo motor sends pulse signals to indicate the damper position to the A/C amplifier. The A/C amplifier activates the motor (normal or reverse) based on these signals to move the air inlet mode selection air inlet control damper to any position, which controls the intake air settings (FRESH, FRESH/RECIRCULATION and RECIRCULATION).

The A/C amplifier communicates with the servo through a communication/driver IC and wiring assembly called the air conditioning harness.

HINT

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

Scheme 106

The air outlet control servo motor sends pulse signals to indicate the damper position to the A/C amplifier. The A/C amplifier activates the motor (normal or reverse) based on these signals to move the mode damper to any position, which controls the air outlet switching.

The A/C amplifier communicates with the servo through a communication/driver IC and wiring assembly called the air conditioning harness.

HINT

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

Scheme 107

The A/C inverter assembly monitors power voltage from the main battery in the circuit. It stops compressor control and stores the DTC when the monitored voltage is outside the specified range.

The output DTC is memorized as previous trouble. Compressor control may not resume unless the power switch is turned off.

Scheme 108

The inverter in the compressor with motor assembly outputs high-voltage to operate the motor. If there is an open or short in the output circuit, the ECU will stop compressor operation and output the DTC. The output DTC will be memorized as a history DTC. The compressor operation remains stopped until both the history and current DTCs are cleared.

The inverter activation signal is sent to the compressor with motor assembly from the power management control ECU. Compressor control is stopped and the DTC is stored if there is an open or short in the signal circuit.

Scheme 109

The temperature sensor of the compressor with motor assembly detects inverter temperature.

If the temperature exceeds the maximum, the compressor with motor assembly stops compressor operation, and this DTC will be stored.

The compressor with motor assembly stops compressor control and outputs this DTC if the rotation load is too large or too small while controlling motor rotation in the compressor with motor assembly.

Possible causes are refrigerant gas leakage, overcharged refrigerant gas, insufficient cooling because of a condenser fan circuit malfunction, or compressor lock.

The compressor with motor assembly monitors the controlling power voltage in the circuit. It stops the compressor circuit and stores the DTC when the monitored voltage is outside the specified range.

The output DTC is memorized as previous trouble. The compressor control may not resume unless the power switch is turned off.

The air conditioning harness connects the A/C amplifier and each servo. The A/C amplifier supplies power and sends operation instructions to each servo through the air conditioning harness. Each servo sends the damper position information to the A/C amplifier.

Scheme 110

The power management control ECU and compressor with motor assembly transmit information to one another via a communication line. Compressor control is stopped and the DTC is stored if communication information is cut off or abnormal information occurs.

The DTC is also detected if high-voltage power supplied from the inverter with converter assembly to the compressor control circuit is shut off.

The output DTC is memorized as previous trouble.

Scheme 111

The DTC is stored if there is insulation trouble with the high-voltage circuits in the air conditioning system. Possible causes are poor insulation in the compressor with motor assembly, or mixing of any oil other than ND-OIL 11 in the refrigerant cycle.

The motor driven with high-voltage is built into the electrical compressor and is cooled directly with refrigerant. Compressor oil (ND-OIL 11) with high insulation performance is used because a leakage of electrical power may occur if regular compressor oil (ND-OIL 8) is used.

Scheme 112

This circuit consists of the A/C control assembly and A/C amplifier. When the A/C control assembly is operated, signals are transmitted to the A/C amplifier through the LIN communication system.

If the LIN communication system malfunctions, the A/C amplifier does not operate even if the A/C control assembly is operated.

Scheme 113

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

Scheme 114

Scheme 115

1. w/o Solar Ventilation System
2. w/ Solar Ventilation System

The PTC heater assembly is installed in the radiator in the heater unit and operates when engine coolant temperature is low and normal heater effectiveness is insufficient.

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

The PTC heater assembly controls PTC heater lines by electric load or the amount of inverter with converter assembly (PCU) output. Therefore, troubleshooting should be performed with other electric components off.

Scheme 116

Scheme 117

Scheme 118

Scheme 119

Scheme 120

Scheme 121

Scheme 122

1. INSPECT PTC HEATER ASSEMBLY Remove the PTC heater assembly. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A19-1 (B) - A20-1 (E) Always Below 1 ohms A19-2 (B) - A20-2 (E) Always Below 1 ohms A19-2 (B) - A20-1 (E) Always Below 1 ohms A19-3 (B) - A20-2 (E) Always Below 1 ohms TEXT IN ILLUSTRATION *1 Component without harness connected (PTC Heater Assembly) NG --> See step 7 OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (PTC HEATER ASSEMBLY - BODY GROUND) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A20-1 (E) - Body ground Always Below 1 ohms A20-2 (E) - Body ground Always Below 1 ohms TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to PTC Heater Assembly) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (PTC HEATER ASSEMBLY - INTEGRATION RELAY) Disconnect the PTC heater assembly connector. Disconnect the engine room relay block and junction block (integration relay) connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A19-1 (B) - 1H-10 (PTC1) Always Below 1 ohms A19-2 (B) - 1H-6 (PTC2) Always Below 1 ohms A19-3 (B) - 1H-9 (PTC3) Always Below 1 ohms A19-1 (B) - Body ground Always 10 kohms or higher A19-2 (B) - Body ground Always 10 kohms or higher A19-3 (B) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to PTC Heater Assembly) *2 Front view of wire harness connector (to Engine Room Relay Block and Junction Block (Integration Relay)) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - INTEGRATION RELAY) Disconnect the A/C amplifier connector. Disconnect the engine room relay block and junction block (integration relay) connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition L17-18 (PTC1) - 1G-17 (PTCA) Always Below 1 ohms L17-38 (PTC2) - 1G-26 (PTCB) Always Below 1 ohms L17-16 (PTC3) - 1G-25 (PTCC) Always Below 1 ohms L17-18 (PTC1) - Body ground Always 10 kohms or higher L17-38 (PTC2) - Body ground Always 10 kohms or higher L17-16 (PTC3) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to Engine Room Relay Block and Junction Block (Integration Relay)) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. REPLACE INTEGRATION NO. 1 RELAY Replace the integration relay. Refer to «REMOVAL»(/toyota/prius-plug-in/2012-2014/remont/body-electrical/#power-distribution-service-information-base) . HINT: Since the integration relay cannot be inspected while it is removed from the vehicle, replace the integration relay with a new or a known good one and check that the condition returns to normal. Check if the same problem occurs again. OK Same problem does not occur. NG --> See step 6 OK --> END (INTEGRATION RELAY WAS DEFECTIVE)
6. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-551393-S01699272352013051500000)
7. REPLACE PTC HEATER ASSEMBLY. Refer to «DISASSEMBLY»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base)

The R/F, TEMP UP (+), and TEMP DOWN (-) switches are located on the steering pad switch RH. The resistance of the steering pad switch RH changes in accordance with switch operation. The A/C control assembly outputs voltage to the steering pad switch RH and reads voltage changes due to the resistance changes that result from switch operation.

HINT

If there is an open in the circuit, the A/C system cannot be operated by the steering pad switch RH.

If there is a short in the circuit, the resulting condition is the same as if the switch were continuously depressed. Therefore, the A/C control assembly cannot be operated by the steering pad switch RH, and the A/C control assembly will not be able to function correctly.

Scheme 123

The integration control and panel sub-assembly (ECO MODE switch) is installed on the instrument panel on the driver side. When the integration control and panel sub-assembly (ECO MODE switch) is turned on, the A/C amplifier receives an integration control and panel sub-assembly (ECO MODE switch) ON signal and controls the air conditioning to enhance fuel efficiency.

When the heater is on, the engine ON request coolant temperature will be set to a lower level. Thus, the length of time that the engine operates to generate the heat necessary to operate the heater will be limited. When the engine coolant temperature drops, the amount of air flow of the blower motor will also decrease. If FOOT/DEF or DEF is selected, or if the temperature is set to MAX HOT, the fuel efficiency control due to the integration control and panel sub-assembly (ECO MODE switch) operation will be canceled.

When the air conditioning is used to cool the vehicle, the power consumption of the compressor will be limited. Initially, the air conditioning will operate normally until the cabin temperature stabilizes. After the cabin temperature stabilizes, the power consumption of the compressor will be limited while stabilizing the cabin temperature. If the temperature is set to MAX COOL, the fuel efficiency control due to the integration control and panel sub-assembly (ECO MODE switch) operation will be canceled.

Scheme 124

Scheme 125

Scheme 126

Scheme 127

Scheme 128

Scheme 129

1. INSPECT AIR CONDITIONING AMPLIFIER Remove the A/C amplifier with the connectors still connected. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition L17-15 (ECOS) - Body ground Power switch on (IG) ECO MODE switch off (when switch is not pressed) 11 to 14 V L17-15 (ECOS) - Body ground Power switch on (IG) ECO MODE switch on (when switch is pressed) Below 1 V TEXT IN ILLUSTRATION *1 Component with harness connected (A/C Amplifier) NG --> See step 2 OK --> See step 5
2. CHECK HARNESS AND CONNECTOR (ECO MODE SWITCH - BODY GROUND) Disconnect the connector from the integration control and panel sub-assembly (ECO MODE switch). Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition L78-5 (E) - Body ground Always Below 1 ohms TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to Integration Control and Panel Sub-assembly (ECO MODE Switch)) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. INSPECT INTEGRATION CONTROL AND PANEL SUB-ASSEMBLY (ECO MODE SWITCH) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition L78-2 (ECU) - L78-5 (E) ECO MODE switch off (when switch is not pressed) 10 kohms or higher L78-2 (ECU) - L78-5 (E) ECO MODE switch on (when switch is pressed) Below 1 ohms TEXT IN ILLUSTRATION *1 Component without harness connected (Integration Control and Panel Sub-assembly (ECO MODE Switch)) NG --> See step 6 OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - ECO MODE SWITCH) Disconnect the connector from the A/C amplifier. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition L17-15 (ECOS) - L78-2 (ECU) Always Below 1 ohms L17-15 (ECOS) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to Integration Control and Panel Sub-assembly (ECO MODE Switch)) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 7
5. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-551393-S01699272352013051500000)
6. REPLACE INTEGRATION CONTROL AND PANEL SUB-ASSEMBLY (ECO MODE SWITCH). Refer to «REMOVAL»(/toyota/prius-plug-in/2012-2014/remont/exteriorinterior-trim/#interior-panels-trim-service-information-base)
7. REPLACE A/C AMPLIFIER. Refer to «REMOVAL»(/toyota/prius-plug-in/2012-2014/remont/automatic-hvac-system/#air-conditioning-system-service-information-base)

The main power source is supplied to the A/C amplifier when the power switch is on (IG).

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

Scheme 130

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

Scheme 131

See also:
• REMOVAL
• REMOVAL
• REMOVAL