HD21 Vent Left Rear Spring

^ In order to determine if the air line or air compressor assembly is the problem, the following actions are required:

^ Disconnect one of the air lines from air compressor drier assembly.

^ Release STAR test button so that ti remains in the HOLD position after code 27 has been displayed for at least 5 seconds.

NOTE: This test step may result in a rapid loss of vehicle ride height.

^ Left rear corner of vehicle has vented down to a normal ride height:

Very slowly or none at all -- DEPRESS STAR test button so that it remains in the TEST position. SERVICE restriction in the airline for left rear corner of vehicle. REPEAT Service Bay Diagnostics. Reading and Clearing Diagnostic Trouble Codes

At a fast or normal rate -- DEPRESS STAR test button down so that it remains in the TEST position. Then GO to HD22.