Functional Tests

Functional Tests

CAUTION: Function Test in run only if diagnosis does not identify concern. Excessive use of the Function Test could overheat the compressor or damage system electronics.

Function tests are run at the end of the Auto Test procedure and are used as an aid to diagnose the system. The only way to enter the Function Test is by first running the Auto Test. During the Function Test, the air suspension control module will attempt to cycle the components as follows:
DTC 23: Vent Rear-During this test, the air suspension control module will attempt to open the vent solenoid as long as the Super Star II Tester button is depressed. The rear of the vehicle will lower.

NOTE: DTC 26 is normally used to inflate the rear air springs after installation. The extended use of this test can cause the auto-resetting circuit breaker in the compressor to open. If this happens, allow the compressor to cool down for 15 minutes. Then, restart the diagnostic procedures.

DTC 26: Compress Rear-During this test, the air suspension control module will attempt to energize the air compressor and open the air spring solenoid as long as the Super Star II Tester button is depressed. The rear of the vehicle will rise.
DTC 31: Air Compressor Relay Toggle-During this test, the air suspension control module will attempt to cycle the 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 is depressed. The compressor will be heard cycling ON and OFF if this test is successful.
DTC 32: Vent Solenoid Toggle-During this test, the vent solenoid 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 depressed. The vent solenoid in the air compressor will be heard cycling ON and OFF if this test is successful.
DTC 33: Air Spring Solenoid Toggle-During this test, both air spring solenoids 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 depressed. The air suspension control module cannot turn one air spring solenoid ON without having the other air spring solenoid turn ON. The circuitry inside the air suspension control module has the air spring solenoids tied together. To verify that both air spring solenoids operate, raise the vehicle on a hoist. Do not turn the air suspension switch OFF. Remain in Function Test DTC 33. Then, touch each air spring solenoid to verify that it is cycling ON and OFF.