Volkswagen Workshop Service and Repair Manuals

Perform check only when performance is poor or engine is shaking because its misfiring.

Special tools, testers, measuring instruments and auxiliary items required

• ◆ → Hand multimeter V.A.G 1526 or multimeter V.A.G 1715

• ◆ → V.A.G 1598/22 test box
• ◆ Diode test lamp V.A.G 1527
• ◆ Adapter set V.A.G 1594
• ◆ Current flow diagram

Check conditions

• ● → Fuse 32 must be OK.
• ● All spark plugs and ignition wiring must be OK.
• ● The battery voltage must be at least 11.5 V.
• ● Engine speed sender must be OK, checking Page 24-57 .
• ● Hall sender OK, checking

Test sequence

• ‒ Switch off ignition.
• ‒ → Pull black 6 pin connector off ignition coils -arrow-.

Checking voltage supply

• ‒ → Measure supply voltage between supply voltage connection (arrow) and engine earth with multimeter and auxiliary cable from V.A.G 1594.
• ‒ Switch on ignition.
       Specification: min. 11.5 V
• ‒ Switch off ignition.

If no voltage was present:

• ‒ Check wiring to fuse 29 using current flow diagram.

If the voltage was at least 11.5 V:

Checking primary resistance

• ● Ignition switched off

• ‒ → Measure primary resistance between connection (arrow) and connector contact 2 using multimeter and auxiliary cable from V.A.G 1594.
       Specification: Max. 100 ω
• ‒ Repeat test at connector contacts 3...6.

If the specifications are not obtained:

• ‒ Replace ignition coils.

If the specifications are obtained:

Checking activation

• ● Ignition switched off

• ‒ → Pull the black and brown 6 pin connectors off the output stage N122.

• ‒ → Check wiring 1...6 between ignition coils 6 pin connector and black 6 pin connector on output stage (N122) for open circuit using current flow diagram.
       Wire resistance: Max. 1.5 ω

If no wiring fault is detected:

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

• ‒ → Check that the earth connection is properly secured on the heat sink for the output stage (arrow).
• ‒ Measure the voltage supply at the brown 6 pin connector for the output stage:
• ‒ Connect diode test lamp V.A.G1527 with auxiliary cables from V.A.G 1594 to contact 1 of brown 6 pin connector and vehicle earth:
• ‒ Switch on ignition.

The LED must light up.

• ‒ Switch off ignition.

If the LED does not light up:

• ‒ Check wiring from connector contact 1 of brown 6 pin connector to fuse 29 using current flow diagram.

If not open circuit can be found:

• ‒ Connect diode test lamp V.A.G1527 to brown 6 pin connector contact 2 and the vehicle battery positive terminal:
• ‒ Switch on ignition.

The LED must light up.

• ‒ Switch off ignition.
• ‒ Repeat test on connector contacts 3...6.

If the activation of the output stage is fault-free:

• ‒ Switch off ignition.
• ‒ Replace output stage (N122).

If the activation of the output stage is interrupted at one or more connector contacts:

• ‒ → Connect test box V.A.G 1598/22 to control unit wiring harness.

• ‒ → Check wiring between brown 6 pin connector and test box for open circuits.
       Contact 1+socket 1
       Contact 2+socket 71
       Contact 3+socket 57
       Contact 4+socket 77
       Contact 5+socket 70
       Contact 6+socket 78
       Wire resistance: Max. 1.5 ω

If no wiring fault is detected:

• ‒ Reconnect the detached connectors.
• ‒ Replace engine control unit
  .