Checking Pressure Relief Valve In Cap:

WARNING: This page is about a different car, the 2003 BMW 530i, 2002 BMW 530i, and 2001 BMW 530i. However, it is still accessible from the selected car via links, so may be relevant.

Detach rubber (1) from hand pump.

Attach special tool 17 0 007/17 0 008.

Fig 1: Preparing Pressure Tester

Courtesy of BMW OF NORTH AMERICA, INC.

Screw cap (1) onto special tool.

Build up pressure with special tool (hand pump) 17 0 002; observe pressure gauge to ascertain when opening pressure is achieved.

Compare opening pressure of pressure relief valve.

Fig 2: Pressure Testing Cap

Courtesy of BMW OF NORTH AMERICA, INC.