Pneumatic Test

The pneumatic test is designed to exercise the pneumatic components of the air suspension. Each air spring is pumped for 5 seconds and vented for 5 seconds while the height sensor is monitored by the Generic Electronic Module (GEM) for the proper ride height transition. If the vehicle fails to pass, a Diagnostic Trouble Codes (DTCs) corresponding to the fault is displayed on the NGS screen. This test thus exercises the air compressor, the compressor relay and related circuitry, the vent solenoid, the air lines, the air spring solenoids, the air springs, and the height sensor. While this test is designed to isolate pneumatic failures, its dependence on the electrical system may yield a pneumatic test DTC when an electrical condition is present. For example, because compressor relay circuit faults and height sensor open circuit faults cannot be detected by the GEM, they may trigger the pneumatic DTCs.