Originally Posted by killcrap

need details. Year Production Date/ Engine Size

Single Axle Air Suspension? If single axle air suspension, check alternator charging voltage. If ok, interrogate EHC fault memory. No faults stored, check shadow memory, if fault stored in shadow memory, perform test plan for pre-drive check delay. The radio interfers with the EHC control unit causing this error, this test plan will delay the pre-drive check until after the radio has powered on.