Tech Tip: What to do if a Chevy Aveo's A/C blows hot air

Aug. 31, 2020
The technician tried all they could think of to fix the A/C before calling ALLDATA Tech-Assist to get some advice.

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 technician 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 technician 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. 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 technician 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 could move 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. 

 Bonus Tech-Assist A/C Tip:

How to test for large A/C leaks when the charging station refuses to charge

Say a vehicle is brought in with no refrigerant in the A/C system or you have completely evacuated the system. If the recovery/charging station determines that there is a “large leak”, it may not allow you to recharge the system. How do you find the leak under those conditions?

Use a nitrogen leak test kit to find the leak. You can fill the system with nitrogen as per the kit’s instructions and listen for any hissing sounds, and/or use the supplied solution to create bubbles at the leak site.

Information provided by ALLDATA

Sponsored Recommendations

Garage Tip: The Value of System Solutions

Learn why inspecting related parts when repairing your vehicle can save you time and money. Avoid future failures and ensure satisfaction! Click to watch now.

Access the Best Learning Resource for Professional Mechanics

Get hands-on tips, updated repair instructions, mounting videos, failure diagnosis, and best practices for professional mechanics. Click to access essential technical info to ...

From the Basics to Innovations - Transmission Technical Training Videos

Explore Schaeffler's portfolio of transmission technical trainings for the LuK brand. Tailored for all skill levels, our modules cover basics to innovations. Click to learn more...

Clutch Release Problems - Diagnosis & Failure Analysis

Explore common clutch release problems and their causes, from hydraulic issues to mechanical faults. Understand diagnostics and solutions for optimal clutch performance.

Voice Your Opinion!

To join the conversation, and become an exclusive member of Vehicle Service Pros, create an account today!