16 00 100 Checking fuel tank and tank ventilation system for leaks

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2013 BMW 128i, 2012 BMW 128i, 2011 BMW 128i, 2010 BMW 128i, and 2009 BMW 128i. However, it is still accessible from the selected car via links, so may be relevant.

Special tools required:

13 3 010
16 1 070
16 1 171
16 1 174

See FUEL SYSTEM - SPECIAL TOOLS (N51, N52K) .

See FUEL SUPPLY SYSTEM - SPECIAL TOOLS (N51, N52K) .

Necessary preliminary tasks:

Remove cover for carbon canister . See 51 71... REMOVING AND INSTALLING/REPLACING COVER FOR CARBON CANISTER (CONVERTIBLE) or 51 71... REMOVING AND INSTALLING/REPLACING COVER FOR CARBON CANISTER (COUPE) .

The following procedure is only applicable to vehicles without the tank leak diagnosis module.

Comply with the following conditions in order to obtain plausible test results:

Content of fuel tank:
1. Maximum 90 %
2. Minimum 13 % (reserve telltale must not light up).
Park the car in the workshop at least 2 hours before the test so that the fuel temperature is approximately that of the workshop temperature (ideal fuel temperature approx. 10... 20°C).

Disconnect line to evaporation strainer (1) from carbon canister.

IMPORTANT: Risk of breakage!
Carefully remove evaporation strainer from carbon canister.

Using special tool 16 1 070, seal opening (2) for evaporation strainer on carbon canister.

Fig 1: Identifying Evaporation Strainer And Seal Opening

Courtesy of BMW OF NORTH AMERICA, INC.

Remove fuel filler cap and connect special tool 16 1 174 to fuel filler neck.

Clamp special tool 16 1 174 on fuel filler neck with adjusting wheel (1).

Fig 2: Identifying Fuel Filler Neck With Adjusting Wheel

Courtesy of BMW OF NORTH AMERICA, INC.

IMPORTANT: Turn pressure regulator on special tool 16 1 171 counterclockwise up to stop.

Connect special tool 16 1 171 using compressed air line (1) to garage compressed air system (8... 10 bar).

Connect pressure sensor (2) from Diagnosis and Information System with a measuring range of 0... 25 bar.

Fig 3: Identifying Special Tool 16 1 171 And Compressed Air Line

Courtesy of BMW OF NORTH AMERICA, INC.

IMPORTANT: Do connect fast-release coupling (3) of special tool 16 1 171.

Select "Measurement" function on Diagnosis and Information System (DIS).
Using pressure regulator on special tool 16 1 171, increase pressure by 0.20 bar.
Connect special tool 16 1 174 to fast-release coupling of special tool 16 1 171.
Wait until the value at the Diagnosis and Information System has levelled out.
Using pressure regulator on special tool 16 1 171, reset gauge pressure in fuel tank to 0.20 bar.

IMPORTANT: Do not under any circumstances increase pressure by more than 0.30 bar as this would result in damage to the fuel tank and venting system.

Using special tool 13 3 010, disconnect delivery line from special tool 16 1 171 to fuel filler neck.

Allow a rest period of approx. 20 sec.

Read off and note down starting pressure value.

Wait approx. 120 sec.

Read off final pressure value and compare with starting pressure value.

Fig 4: Identifying Special Tool 13 3 010 And Delivery Line

Courtesy of BMW OF NORTH AMERICA, INC.

Measurement evaluation:

Pressure drop up to 0.01 bar:
System OK
Pressure drop over 0.02 bar:

System leaking beyond permitted levels

If the system is leaking, a leak test must be carried out and the defective components replaced.