Volkswagen Workshop Service and Repair Manuals

Special tools, testers, measuring instruments and auxiliary items required

• ◆ Test box V.A.G 1598/18
• ◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
• ◆ Adapter set V.A.G 1594
• ◆ Current flow diagram

Test conditions

• ● Fuel pump relay OK
• ● Fuse 18 OK.

Checking voltage supply

• ‒ → Separate 4 pin connector to Lambda probe (G39) -1-.
• ‒ Connect multimeter using adapter cable from V.A.G 1594 to measure voltage on connector contacts 1+2.
• ‒ Start engine and measure voltage.
       Specification: at least 11 V
• ‒ Switch off ignition.

If no voltage is present:

• ‒ → Connect test box V.A.G 1598/18 to control unit wiring loom.
• ‒ Switch on ignition.
• ‒ Bridge test box sockets 1+25 with aux. cables from V.A.G 1594. The fuel pump must run.
• ‒ Observe display on multimeter.
       Specification: min. 11 V

If the specification is not obtained:

• ‒ Check wiring connections according to relay plate according to current flow diagram.