Diagnostic Aids

If a leak exists in an air line or air spring, if vehicle is overloaded, or if compressor is damaged or incapable of providing necessary amount of air needed, the height sensor may need to signal Vehicle Dynamics Module (VDM) to pump more air. VDM maintains a record of continuous run time to compressor. When run time exceeds a set time programmed into VDM, a Code C1820 will set and compressor is shutoff. After about 7 minutes of cool down time, VDM will restore compressor operation.

1) Check Codes  If Code C1820 is a continuous (intermittent) code, go to next step. If Code C1820 is not stored, wait 10 minutes. Repeat ON-DEMAND SELF-TEST and PNEUMATIC TEST under DIAGNOSTIC TEST MODE  .

2) Perform Pneumatic Test  Perform PNEUMATIC TEST under DIAGNOSTIC TEST MODE  . If vehicle does not past test, go to TEST V  . If vehicle passes test, no problem is indicated at this time. Check with vehicle owner to see if vehicle has been overloaded.