Audi Workshop Service and Repair Manuals

Special tools and workshop equipment required

• ◆ V.A.G 1526 A
• ◆ V.A.G 1527 B
• ◆ V.A.G 1594 A
• ◆ V.A.G 1598/31
• ◆ VAS 5051

• or

• ◆ V.A.G 1551 with V.A.G 1551/3 A

Fitting location=>Fitting locations overview

=> Motronic injection and ignition system; Repair group 24; Servicing Motronic injection system; Fitting locations overview

Test requirement:

• ● Final control diagnosis has been performed

Testing internal resistance

• ‒ Unplug connector from secondary air inlet valve -N112.

• ‒ → Connect multimeter to valve (resistance measurement range)
• ‒ Specification: 25 ... 35 ω
• ‒ If the reading does not match the specification, renew secondary air inlet valve -N112.

Checking voltage supply

• ‒ Unplug connector from secondary air inlet valve -N112.

• ‒ → Connect voltage tester V.A.G 1527 B as follows:

• ‒ Operate starter briefly.
• ‒ The LED should light up.

If the LED does not light up:

• ‒ Carry out the following tests (marked with dots):

• ● → Test fuse No. S234 (in fuse box, socket 34)

• ● → Test for open circuit in wiring from fuel pump relay to connector contact 1 via fuse -S234 (socket 34 in fuse box):

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

• ● Test fuel pump relay

=> Motronic injection and ignition system; Repair group 24; Servicing Motronic injection system; Testing fuel pump relay and activation

Testing activation

• ‒ → Connect voltage tester V.A.G 1527 B between contacts 1 and 2 using auxiliary cables from V.A.G 1594 A.

• ‒ Start final control diagnosis and select secondary air inlet valve -N112.

=> Motronic injection and ignition system; Repair group 01; Final control diagnosis

• ‒ The LED should flash.

If the LED lamp does not flash or if it lights up continuously:

• ‒ Connect test box V.A.G 1598/31 to wiring harness for engine control unit.Do notconnect to the engine control unit itself.

=> Motronic injection and ignition system; Repair group 24; Servicing Motronic injection system; Testing fuel pump relay and activation

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

• ‒ Rectify any open/short circuit as necessary.

If the wiring is OK:

• ‒ Fit a new engine control unit.

=> Motronic injection and ignition system; Repair group 24; Servicing Motronic injection system; Renewing engine control unit