If your check air suspension light came on or you’re experiencing other common symptoms of problems with the air suspension like a sagging vehicle, follow these steps in this article and video and to diagnose your vehicle’s air suspension yourself.
How to Diagnose the Air Suspension for a Check Air Suspension Warning Light
If the check air suspension warning light came on, or a similar message like, “Stop, car riding low,” this means the module has noticed your vehicle is riding low and has a problem.
General Steps to Check the Air Suspension
- Check for Fault Codes with a Scan Tool
A scan tool capable of monitoring the air suspension system will let you read fault codes. Check for any fault codes for the suspension.
With certain scanners you can also read the data and see if the sensors are working. You can raise the vehicle and graph the sensors to check for a smooth transition line, which is a sign the sensors are working.
- Check Any Level Sensors
This example is for a rear axle level sensor, which tells the computer when to turn the pump on or exhaust pressure to the rear suspension. If the sway bar broke near the sensor, that would cause a problem.
- Check Modules If You Have a Sensor-Related Code
This step is only necessary for codes related to this part of the system. In this example, featured in the video above at 2:00, has the module located on the passenger side, underneath the seat at the kick panel.
Check your owner’s manual for the location of the module fuse. Find the fuse for the module and disconnect the electrical connector. You can loosen it from the top with one hooked pick, and pull the fuse up with another hooked pick. Then check the fuse and see if it’s blown.
- Check the Pump
The pump in this example is located in front of the driver side front tire. Depending on the vehicle, the air suspension may be at the front and rear or only the rear.
Check the connectors at the pump. Disconnect them and check for damage like melting or discoloration.
A melted connector, like in the image above, may not be the end of the problem. This is a sign of a connection issue and could blow a fuse.
Before checking the pump, make sure the vehicle is on the ground. If the rear suspension is hanging, it won’t tell the pump to turn on.
Check the connector for power and ground with a test light to confirm electricity is reaching the pump. Connect a jumper harness to test the pump and make sure it’s working correctly.
If the pump connectors are in good condition and you don’t need a jumper harness, listen to the pump. A noisy pump is a sign that it’s working. A defective pump won’t make any noise, and that’s usually from an electrical issue.
A pump turning on and off intermittently is a sign of an air leak.
More tips on how to check the air suspension
How to Diagnose & Fix a Bad Air Suspension Kit in GM Vehicles
- Check the Lines and Airbags for Leaks
Spray the lines and airbags of your air suspension system with soapy water to check for air leaks. Cracks and other damage like rust can lead to leaks that can also sometimes be heard by hear.
Listen for whirring sounds of air escaping and check the airbags for leaks.
The airbag in the image above has a cover that needs to be removed. Then, if the water bubbles with the system running, you’ll know where the leak is.
How to Find Tire Leaks with Soapy Water
Replace Air Suspension Parts & More with Our How-to Videos
Our how-to videos work for mechanics and DIYers of all skillsets. Learn how to replace air suspension parts and more with step-by-step instructions and tips from our expert mechanics.