(Requirements For Driving Into The Workshop - AH00.00-P-0021-01RFW)

Model 253.992/993 

In order to be permitted to drive a hydrogen-powered vehicle into the workshop, certain requirements must be fulfilled. In some instances, carry out certain activities outdoors before driving into the workshop.

Observe corresponding workshop literature.

The required test steps are shown below, you must carry these out in the specified sequence:

Courtesy of MERCEDES-BENZ USA

Instrument cluster is operational (A1), no hydrogen warning message and no audible hydrogen leakage 

Driving into the workshop (1) is permitted.

Instrument cluster is defective (A2), but no hydrogen warning message and no audible hydrogen leakage 

1. Connect vehicle diagnosis system and read out fault memory (B).

   Check whether there is a hydrogen-relevant fault (B2).

   If there is no hydrogen-relevant fault (B1), driving into the workshop (1) is permitted. 

2. If it is necessary to remove one or both fuel tanks or the fuel cell (C) for subsequent operations, also carry out the following operations: 
   • Inert fuel tank or fuel tanks (C1), for removal of one or both fuel tanks.
   • Flush fuel cell stack (C1), for removal of the fuel cell.
   • Close manual valves of fuel tanks (C2).
   • Drain pressure in fuel cell system (D).
3. If there is a hydrogen-relevant fault (B2): 
   • Close manual valves of fuel tanks (C2).
   • Drain pressure in fuel cell system (D).

   Then driving into the workshop (1) is permitted.

Courtesy of MERCEDES-BENZ USA

Audible hydrogen leakage (E) 

1. Secure vehicle and leave to drain independently until hydrogen loss amounts to < 8000 ppm (I).
2. Perform leak test quick test (G).

   If the measured hydrogen loss > 8000 ppm (H2), secure the vehicle again and leave to drain independently.

   Only continue check when measured hydrogen loss amounts to < 8000 ppm (H1).

3. Connect vehicle diagnosis system and read out fault memory (B).
4. If it is necessary to remove one or both fuel tanks or the fuel cell (C) for subsequent operations, also carry out the following operations: 
   • Inert fuel tank or fuel tanks (C1), for removal of one or both fuel tanks.
   • Flush fuel cell stack (C1), for removal of the fuel cell.
5. Close manual valves of fuel tanks (C2).
6. Drain pressure in fuel cell system (D).

   Then driving into the workshop (1) is permitted.

Before opening the hydrogen system or a hydrogen warning message in the instrument cluster (F) 

1. Perform leak test quick test (G).

   If the measured hydrogen loss > 8000 ppm (H2), secure the vehicle again and leave to drain independently.

   Only continue check when measured hydrogen loss amounts to < 8000 ppm (H1).

2. Connect vehicle diagnosis system and read out fault memory (B).
3. If it is necessary to remove one or both fuel tanks or the fuel cell (C) for subsequent operations, also carry out the following operations: 
   • Inert fuel tank or fuel tanks (C1), for removal of one or both fuel tanks.
   • Flush fuel cell stack (C1), for removal of the fuel cell.
4. Close manual valves of fuel tanks (C2).
5. Drain pressure in fuel cell system (D).

   Then driving into the workshop (1) is permitted.