Summary of Auto AC Maintenance and Common Faults and Case Analysis of Automobile Air Conditioning 8

Case 1

Obstacle phenomenon: In a 2007 Sagitar 1.6L sedan, customers complained that the air conditioner was not cool enough when the vehicle was hot, and sometimes there was no cold wind blowing out after more than ten minutes of starting.

Inspection and analysis: Use the fault diagnosis instrument to detect that all systems have no fault memory. To read the data stream, select 08 (air conditioning) -08 (data stream).

According to the detected data, it can be seen that the temperature of the auto ac evaporator is high and the torque required by the auto ac compressor is low. The normal working current of the compressor is about 0.8A, and as the indoor temperature gradually drops, the air-conditioning control unit will gradually reduce the compressor current to reduce the output power. At this time, the evaporator temperature is 12°C and the compressor current has been adjusted to the maximum value. At this time, it can be analyzed that the air conditioning control unit judges that the cooling power is insufficient (the evaporator temperature is too high), so it outputs cooling with high power. But the torque required by the compressor is 2~3N·m, which is lower than the standard value. In other words, the air-conditioning control unit hopes that the car ac compressor will work at 100% full load, but the compressor actually only needs 50% torque to achieve full load work. From this, it can be judged that the compressor solenoid valve N280 or the piston in the compressor is malfunctioning, resulting in insufficient output power and the air conditioner is not cool enough.

car air conditioning


Post time: Nov-22-2021