Functional Test Description

CAUTION: Excessive use of the Functional Tests could overheat the compressor or damage air springs or system electronics.

Functional Tests are available at the third stage of Auto Test procedure. During the Functional Test the control module will attempt to cycle the components as follows:

DTC 23/24/25: Vent Right/Left Both Rear-The control module attempts to open the vent solenoid valve and air spring solenoid valves while the Super STAR II Tester button is pressed. The rear of the vehicle will lower.

DTC 26/27/28: Compress Right/Left/Both Rear- The control module attempts to energize the air compressor and open the air spring solenoid valves as long as the star tester button is pressed. The rear of the vehicle will rise.

NOTE: DTC 28 is normally used to inflate the air spring after installation.

DTC 31: Air Compressor Relay Toggle-The control module attempts to cycle the air compressor relay on for one second and off for one second repeatedly. This cycle will repeat for as long as the Super STAR II Tester button is pressed. The air compressor will be heard cycling on and off if this test is successful.

NOTE: The extended use of the test for DTC 31 can cause the self-resetting circuit breaker in the air compressor to open. If this happens, allow the air compressor to cool down for 15 minutes. Then, restart this test.

DTC 32: Vent Solenoid Valve Toggle-The vent solenoid valve is opened for one second, then closed for one second. This cycle will repeat for as long as the Super STAR II Tester button is pressed. The vent solenoid valve in the air compressor assembly will be heard cycling on and off if this test is successful.

DTC 33: Air Spring Solenoid Valve Toggle-Both air spring solenoid valves will be opened for one second, then closed for one second repeatedly. This cycle will repeat for as long as the Super STAR II Tester button is pressed. To verify that both solenoid valves operate, raise the vehicle on a hoist. Do not turn the air suspension switch off. Remain in Functional Test DTC 33. Then, touch each air spring solenoid valve to verify that it is cycling on and off. Refer to the Function Test Diagnostic Trouble Code Tests and Associated Procedures