Volkswagen Workshop Service and Repair Manuals

Special tools, testers, measuring instruments and auxiliary items required

• ◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
• ◆ 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

Check conditions

• ● The battery voltage must be at least 11.5 V.
• ● Coolant temperature at least 85 °C.
• ● All electrical consumers, e.g. lights and rear window heating must be switched off
• ● If the vehicle is equipped with an air conditioner, this must be switched off.
• ● On vehicles with automatic gearbox selector lever in "P" or "N" position

Test sequence

• ‒ Connect fault reader V.A.G 1551 (V.A.G 1552). Start engine and select "Address word" 01 of engine control unit. When doing this the engine must be running at idling speed.
  (Connecting fault reader and selecting engine control unit .)

• ‒ Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

• ‒ Press keys 0, 0 and 1 for "Display group number 1" and confirm entry with Q key.

• ‒ Check whether the coolant temperature is above 85 °C in display zone 2.
• ‒ Press C key.

• ‒ Press keys 0, 0 and 9 for "Display group number 0" and confirm entry with Q key.

• ‒ Check mass of air drawn in, in display zone 2.
       Specification: 3.00...5.00 g/s
• ‒ Press the ⇒key.
• ‒ Press keys 0 and 6 for the "End output" function and confirm input with the Q key.
• ‒ Switch off ignition.

If the specifications are not attained or there is a fault in fault memory relating to the air mass meter,

• ‒ Check the voltage supply for the air mass meter (G70) => Page 24-34 .

Testing power supply to air mass meter

Vehicles with 4 pin connector

• ‒ → Pull the 4 pin connector -1- off air mass meter -2-.
• ‒ Connect multimeter to measure voltage on connector contacts 3 and engine earth.
• ‒ Start engine and run at idling speed.

•      Specification: 11...15 V

• ‒ Switch off ignition.
• ‒ If the voltage supply is OK, test the signal wire and earth wire => Page 24-36 .

If no voltage was present:

• ‒ → Check wiring from contact 3 to fuel pump relay (J17) according to current flow diagram.

=> Current flow diagrams, Electrical fault finding and Fitting locations binder

Vehicles with 6 pin connector

• ‒ Pull 6 pin connector off air mass meter.

Note:

Pin 6 vacant.

• ‒ → Connect multimeter to measure voltage at connector contact 5 and engine earth.
• ‒ Start engine and run at idling speed.

•      Specification: 11...15 V

• ‒ Switch off ignition.
• ‒ If the voltage supply is OK, test the signal wire and earth wire => Page 24-36 .

If no voltage was present:

• ‒ Check wiring from connector contact 5 to voltage supply relay (J271) according to current flow diagram.

=> Current flow diagrams, Electrical fault finding and Fitting locations binder

Continued for all vehicles

Testing signal wiring for air mass meter

• ‒ → Connect test box V.A.G 1598/18 to control unit wiring loom.

Vehicles with 4 pin connector

• ‒ Check wiring between test box and 4 pin connector for open circuit using current flow diagram.
       Contact 1+earth
       Contact 2+socket 16
       Contact 4+socket 17
       Wire resistance: Max. 1.5 ω

Vehicles with 6 pin connector

• ‒ Check wiring between test box and 6 pin connector for open circuit according to current flow diagram.
       Contact 1+earth
       Contact 2+socket 16
       Contact 3+socket 17
       Wire resistance: Max. 1.5 ω

Continued for all vehicles

• ‒ Additionally check wires all for short to one another.
       Specification: ∞ω

If no wiring fault is detected:

• ‒ Renew air mass meter (G70).