Audi Workshop Service and Repair Manuals

Special tools and workshop equipment required

• ◆ V.A.G 1526 A
• ◆ V.A.G 1594 A
• ◆ V.A.G 1598/31

Note:

The Motronic current supply relay -J271 supplies voltage to the ignition coils with output stages and to the engine control unit (pin 121).

Test requirement:

• ● Fuse No. 229 OK (in fuse box, socket position 29)

Test sequence

• ‒ → Unplug 3-pin connector from one ignition coil.
• ‒ Connect multimeter (voltage measurement range) as follows:

• ‒ Switch on ignition.
• ‒ Specification: approx. battery voltage

• ‒ → Remove rubber seal from plenum chamber in direction of arrow-.
• ‒ Remove plenum chamber cover -1- from the front.

• ‒ → Remove cover for electronics box in plenum chamber -arrows-.

• ‒ → Unplug current supply relay -3-.

• ‒ → Test for open circuits in the following wiring connection according to current flow diagram:

• ‒ Rectify any open circuit as necessary.

If the wiring is OK:

• ‒ Test supply voltage for Motronic current supply relay -J271 .
• ‒ Test activation of Motronic current supply relay -J271 => Page 28-25.

Checking voltage supply

• ‒ → Connect multimeter (voltage measurement range) as follows:

• ‒ Specification: approx. battery voltage

If the specification is not attained:

• ‒ Check for open circuit in wiring between central electrics unit and current supply relay.

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

If no fault is detected in the wiring:

Checking activation

• ‒ → Connect multimeter (voltage measurement range) as follows:

• ‒ Switch on ignition.
• ‒ Specification: approx. battery voltage

If the specification is not attained:

• ‒ Switch off ignition.
• ‒ Connect test box V.A.G 1598/31 to wiring harness for engine control unit. Do not connect to the engine control unit itself.
  => Page 24-20.

• ‒ → Test for open circuit and short to positive or earth in the following wiring connections:

• ‒ Rectify any open/short circuit as necessary.

If no fault is found:

• ‒ Fit a new Motronic current supply relay -J271.