Vehicle: 2010 Mercedes Benz G 550 (463.236), V8-5.5L (273.963)

Mileage: 62,764

Problem: The owner of this Mercedes G 550 was going on a long road trip and wanted his seat’s lumbar function to operate correctly.

Case Details: The technician connected a scan tool but found no diagnostic trouble codes in any modules. Since this is a pneumatic system, next the technician accessed the lumbar valve body in the back of the seat to see if there is any signs of leaks or damaged lines.

NOTE: This system can also be pressurized like an evaporative (EVAP) system with a smoke machine to locate a leak. Additionally, this system has a similar safety function as air suspension. It will shut the air pump off if it detects any loss in pressure.

The technician smoke tested the seat’s pneumatic system and found the leak coming from the hose manifold under the carpet.

Confirmed Repair: He replaced the damaged hose manifold assembly as a unit and the lumbar function worked as designed. Problem solved!