If it is necessary to check the fuel injection system with the engine off, remove the relay and short-circuit terminal 30 and terminal 87 with a short jumper wire with a diameter of 1.5 mm. The fuel pump relay on the 520i/525i/524td models is brown, and on the 530i/535i models it is orange.
Caution: When checking the fuel pump relay, the battery must be charged.
Check fuse #23.
Pull out the relay.
Connect the voltmeter to terminal 30 (+) and 85 (-) on the relay pad. Specified value: 12 Volts.
Otherwise, connect a voltmeter to terminal 30 and ground.
If the voltmeter readings are approximately 12 volts, check the brown-green wire for a break in the electrical diagram. If the wire is intact, check the red wire in the electrical diagram and replace it if necessary.
Turn on the ignition.
Connect a voltmeter to terminal 86 (+) and ground. Specified value: about 12 volts. Otherwise, check the red-white wire for breakage according to the electrical diagram and replace it if necessary.
Check for signals from the speed sensor (work at a service station).
Short-circuit terminals 30 and 87. If the pump starts, replace the fuel pump relay. Otherwise, ring the green-violet wire at the fuel pump and, if necessary, replace the wire.
(The original article is available on the website «BMWMan.ru»)