Remove/install hydrogen sensor in fuel cell exhaust air pipe

AR06.40-P-0002RFW

Remove/install hydrogen sensor in fuel cell exhaust air pipe

05.10.2018

Engine

780 in model 253.992/993

1

Line bracket

5

Clamp

2

Electrical connector

6

Fuel cell exhaust end pipe

3

Electrical connector

7

Rear exhaust air pipe

4

Bolts

8

Dust cap

9

Electrical connector

10

Bolts

B72/6

Hydrogen sensor 1

R53

Hydrogen sensor heating element 1

11

O-ring

12

O-ring

B72/6

Hydrogen sensor 1

R53

Hydrogen sensor heating element 1

S7

High-voltage disconnect device

 Danger

Risk of explosion caused by escaping hydrogen or overheating of the fuel tanks when working on the hydrogen system. Risk of frostbite to body parts caused by escaping gas and by touching component parts carrying gas when emptying fuel tanks. Risk of asphyxiation caused by inhalation of air diluted by hydrogen. Risk of burn injuries by coming into contact with an invisible pale blue hydrogen flame.

AS00.00-Z-0030-01B

Topical note

Notes on fuel cell system

AH00.00-P-0022-01RFW

Topical note

Information on preventing damage to electronic components due to electrostatic discharge

AH54.00-P-0001-01A

Notes on safety-relevant components

AH00.00-Z-0019-01A

 

Remove/install

1

Ensure that the requirements for driving into the workshop are fulfilled.

Topical note

Requirements for driving into the workshop

AH00.00-P-0021-01RFW

2

Print out "tank system, fuel cell, form event log," fill out, and attach to the vehicle somewhere clearly visible.



OF00.00-P-3000-21RFW

3

Actuate high-voltage disconnect device (S7), as shown in picture sequence (A, B, C), and secure with a shackle-type connector.

 Installation:
Carefully connect high-voltage disconnect device (S7) as shown in picture sequence (D, E, F).
High-voltage disconnect device (S7) will otherwise be damaged.

 Keep the key for the shackle-type lock of the high-voltage disconnect device (S7) in a separate location accessible to authorized personnel only.

 Installation: Check high-voltage disconnect device (S7) for damage.

If damage is present,



Remove contacts from coupling housing of high-voltage disconnect device (S7) and replace high-voltage disconnect device (S7).

Remove/install contacts from coupling housing of high-voltage disconnect device.

AR00.19-P-0120-31A

 New passenger car wiring harness repair kit

*220589049900

 Unlocker with ejector MLK 1.2_plug

*220589019925

 Wiring harness repair kit, basic

*000589139900

4

Remove rear underfloor paneling.

AR61.30-P-1001RFW

5

Release line bracket (1).

6

Disconnect electrical connectors (2, 3).

7

Unscrew screw/bolts (4).

 Screw, exhaust air tailpipe to holder

*BA49.10-P-1011-02S

8

Release clamp (5).

 Hose clamp pliers

*454589003700

9

Remove fuel cell exhaust end pipe (6) from rear exhaust air pipe (7).

10

Remove dust cap (8) upwards.

11

Detach electrical connection (9).

12

Unscrew hydrogen sensor 1 (B72/6) from hydrogen sensor heating element 1 (R53) and remove in upward direction.


Carefully remove hydrogen sensor 1 (B72/6) upwards in an axially symmetrical manner.
Hydrogen sensor 1 (B72/6) will otherwise be damaged.

 Installation: Check O-ring (11) at hydrogen sensor 1 (B72/6) for damage and that it is correctly seated.

 Hydrogen sensor in exhaust air pipe at heating unit

*BA06.40-P-1005-01B

If there is a problem,



Correctly position and/or replace O-ring (11).

13

Unscrew screws (10) and remove hydrogen sensor heating element 1 (R53).

 Installation: Check O-ring (12) at hydrogen sensor heating element 1 (R53) for damage and that it is correctly seated.

 Bolt, hydrogen sensor heating unit to exhaust air tailpipe

*BA06.40-P-1001-01B

If there is a problem,



Correctly position and/or replace O-ring (12).

14

Install in the reverse order.

 Sensors

Number

Designation

Engine 780 in model 253.992/993
with code ME02 (Fuel cell)

BA06.40-P-1001-01B

Bolt, hydrogen sensor heating unit to exhaust air tailpipe

M6

Nm

8

 Sensors

Number

Designation

Engine 780 in model 253.992/993
with code ME02 (Fuel cell)

BA06.40-P-1005-01B

Hydrogen sensor in exhaust air pipe at heating unit

Nm

16

 Exhaust system

Number

Designation

Engine 780 in model 253

BA49.10-P-1011-02S

Screw, exhaust air tailpipe to holder

M6

Nm

8