Inspection and Verification

WARNING: Before carrying out a road test, make sure the vehicle is safe to do so. Failure to follow this instruction may result in personal injury

CAUTION: Diagnosis by substitution from a donor vehicle is NOT acceptable. Substitution of control modules does not guarantee confirmation of a fault and may also cause additional faults in the vehicle being checked and/or the donor vehicle

NOTE: Check and rectify basic faults before beginning diagnostic routines involving pinpoint tests

Verify the customer concern

Visually inspect for obvious signs of mechanical or electrical damage

VISUAL INSPECTION

Mechanical	Electrical
Expansion chamber Air leakage Air springs Reservoir Suspension air supply unit Suspension air supply unit air filter Pipework and unions Front and rear height sensor installation Front and rear accelerometer installation Valve block(s)	Battery Fuse(s) Wiring harness physical damage or water ingress Loose or corroded electrical connectors Air suspension control switch Controller Area Network (CAN) circuits Height sensors Accelerometers Valve block(s) Chassis Control Module (CHCM)

If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step
Use the approved diagnostic system or a scan tool to retrieve any diagnostic trouble codes before moving onto the symptom chart or Diagnostic Trouble Code(s) (DTC) index
- Make sure that all DTC are cleared following rectification