Tech Tips (by ALLDATA): Chevy Aveo A/C blows hot air

2009 Chevrolet Aveo Lt

TECH TIPS (courtesy of ALLDATA)

Vehicle: 2009 Chevrolet Aveo, L4-1.6L

Mileage: 98,266

Problem: The vehicle was brought to the shop because the A/C was not working.

Details: The tech connected a scan tool and found no diagnostic trouble codes. Next he checked to be sure all the related fuses had battery (B+) voltage. They did. After that, the tech verified that the vehicle had a manual HVAC system with a V5 compressor, then connected his A/C gages. The refrigerant level was low, and the A/C compressor clutch would not engage.

He charged the A/C system with 1.1 lbs. of refrigerant. NOTE: The low-side and high-side refrigerant pressures at idle were: 75/140 PSI. At 2500 RPM, they were: 80/140 PSI. The A/C lines were warm, and the radiator cooling fan was not running. He replaced the A/C pressure sensor, but it did not help. At this point he called ALLDATA Tech-Assist.

The Tech-Assist consultant advised to first verify that the evaporator temperature sensor, engine coolant sensor and high-pressure sensor readings were within specifications. He added that, if the tech found no problems, he should check the A/C compressor control valve in the back of the compressor for debris and make sure that the valve moved freely.


Confirmed Repair: After verifying that all three sensor values were within specifications, the tech inspected the A/C compressor control valve at the back of the compressor. It was stuck. He replaced the control valve and the air conditioner blew cold air again. Fixed!