Problem Symptoms Table
WARNING: This page is about a different car, the 2006 Lexus IS 350 and 2006 Lexus IS 250. However, it is still accessible from the selected car via links, so may be relevant.
AIR CONDITIONING SYSTEM
PROBLEM SYMPTOMS TABLE
| Symptom | Suspected area |
|---|---|
| All functions of the A/C system do not operate | 1. IG power source circuit |
| 2. Back-up power source circuit | |
| 3. A/C amplifier | |
| Air Flow Control: No blower operation | 1. Blower motor circuit |
| 2. A/C amplifier | |
| Air Flow Control: No blower control | 1. Blower motor circuit |
| 2. A/C amplifier | |
| Air Flow Control: Insufficient air flow | 1. Blower motor circuit |
| 2. A/C amplifier | |
| Temperature Control: No cool air comes out | 1. Refrigerant volume |
| 2. Refrigerant pressure | |
| 3. Pressure switch circuit | |
| 4. Low pressure sensor circuit | |
| 5. Compressor circuit | |
| 6. Compressor lock sensor circuit | |
| 7. Compressor solenoid circuit | |
| 8. Air mix control servo motor circuit (Driver side) | |
| 9. Air mix control servo motor circuit (Passenger side) | |
| 10. Evaporator temperature sensor circuit | |
| 11. Room temperature sensor circuit | |
| 12. Ambient temperature sensor circuit | |
| 13. Expansion valve | |
| 14. A/C amplifier | |
| 15. ECM | |
| Temperature Control: No warm air comes out | 1. Air mix control servo motor circuit (Driver side) |
| 2. Air mix control servo motor circuit (Passenger side) | |
| 3. Evaporator temperature sensor circuit | |
| 4. Room temperature sensor circuit | |
| 5. Ambient temperature sensor circuit | |
| 6. A/C amplifier | |
| 7. ECM | |
| Temperature Control: Output air is warmer or cooler than the set temperature or response is slow. | 1. Refrigerant volume |
| 2. Refrigerant pressure | |
| 3. Solar sensor circuit (Driver side) | |
| 4. Solar sensor circuit (Passenger side) | |
| 5. Room temperature sensor circuit | |
| 6. Ambient temperature sensor circuit | |
| 7. Air mix control servo motor circuit (Driver side) | |
| 8. Air mix control servo motor circuit (Passenger side) | |
| 9. Cool air bypass damper control servo motor circuit | |
| 10. Air inlet control servo motor circuit | |
| 11. Radiator unit sub-assembly | |
| 12. Expansion valve | |
| 13. A/C amplifier | |
| 14. ECM | |
| Temperature control: No temperature control (only Max. cool or Max. warm) | 1. Air mix control servo motor circuit (Driver side) |
| 2. Air mix control servo motor circuit (Passenger side) | |
| 3. Cool air bypass damper servo motor circuit | |
| 4. Room temperature sensor circuit | |
| 5. Ambient temperature sensor circuit | |
| 6. Evaporator temperature sensor circuit | |
| 7. Solar sensor circuit (Driver side) | |
| 8. Solar sensor circuit (Passenger side) | |
| 9. A/C amplifier | |
| Engine coolant does not warm up quickly when the engine is cold. (PTC heater does not operate) | 1. PTC heater circuit |
| 2. A/C amplifier | |
| No air inlet control | 1. Air inlet control servo motor circuit |
| 2. A/C amplifier | |
| No air flow mode control | 1. Air outlet control servo motor circuit |
| 2. A/C amplifier | |
| Engine idle up does not occur, or is continuous | 1. Compressor circuit |
| 2. Compressor lock sensor circuit | |
| 3. Compressor solenoid circuit | |
| 4. A/C amplifier | |
| Blinking of A/C indicator | 1. Compressor solenoid circuit |
| 2. A/C amplifier | |
| Diagnostic trouble codes are not recorded. Set mode is cleared when ignition switch is turned OFF. | 1. Back-up power source circuit |
| 2. A/C amplifier |