Volkswagen Workshop Service and Repair Manuals

Special tools, workshop equipment, test and measuring appliances and auxiliary items required

• ◆ V.A.G 1598/31 Test box
• ◆ V.A.G 1527 B Diode test lamp
• ◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
• ◆ V.A.G 1594 A Adapter set
• ◆ V.A.G 1526 Hand multimeter
• ◆ Current flow diagram

Test conditions

• ● → Fuse SB30 must be OK.

Test sequence

• ‒ Pull 6-pin connector (black) off EGR valve , item 12

• ‒ → Connect multimeter to contacts 2 and 4 of 6-pin connector for voltage measurement.
• ‒ Switch on ignition.
       Specification: min. 4.5 V

If the specification is not attained:

• ‒ Switch off ignition.

• ‒ → Connect test box V.A.G 1598/31 to control unit wiring harness. The engine control unit remains disconnected.

• ‒ → Check wiring for open circuit between test box and 6-pin connector using current flow diagram.
       Contact 2 and test box socket 98
       Contact 4 and test box socket 108
       Contact 6 and test box socket 100
       Wire resistance: max. 1.5ω
• ‒ Additionally check wiring for short to one another, and for short to positive or earth.

If the specification is obtained:

• ‒ Connect engine control unit to test box V.A.G 1598/31 and reconnect 6-pin connector to EGR valve.
• ‒ Connect the fault reader V.A.G 1551 (V.A.G 1552). Then switch ignition on and select engine control unit with the "Address word" 01.

=> Repair group 01; Self-diagnosis general: Connecting fault reader V.A.G 1551 and selecting engine electronics control unit.

• ‒ Initiate final control diagnosis and select EGR valve (N18):

=> Repair group 01; Final control diagnosis; Performing final control diagnosis

• ‒ Connect diode test lamp V.A.G 1527 B to test box socket 100 and earth using adapter from V.A.G 1594.
       The LED must flash.
• ‒ Proceed with final control diagnosis until completed.
• ‒ Press keys 0 and 6 for the "End data transfer" function and confirm input with the Q key.
• ‒ Switch off ignition.
• ‒ Depending on conditions, renew following components:

LED flashes:

• ‒ Renew EGR valve (N18) with potentiometer (G212).

• ‒ Erase learnt values and re-adapt engine control unit

=> Repair group 24; Engine control unit; Erasing learnt values and adapting engine control unit to throttle valve control part and EGR valve

If no wiring fault is detected and the LED does not flash:

• ‒ Renew engine control unit.

=> Repair group 24; Engine control unit; Renewing engine control unit