Testing solenoid valves for camshaft timing control: Audi 2.7 (AGB, AZB)

AZB
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

Start final control diagnosis and select solenoid valves for camshaft adjustment.

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

If one of the valves is not activated (does not click) during final control diagnosis:

Testing internal resistance

Switch off ignition.
Unscrew bolts -arrows- and remove engine cover panels -A...C-.

Remove air duct -arrows-.

Unplug electrical connector on relevant solenoid valve.
Connect multimeter to valve (resistance measurement range)
Specification: 10 ... 18ω

If the specification is not obtained:

Fit a new valve.

Checking voltage supply

Unplug connector on relevant valve.
Connect voltage tester V.A.G 1527 B as follows:

Connector / Contact · Measure against
1 · Engine earth

Operate starter briefly.
The LED should light up.

If the LED does not light up:

Carry out the following tests (marked with dots):

Check fuse for solenoid valves for camshaft timing control.

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

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

Rectify any open circuits.

If no fault is found:

Test fuel pump relay.

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

Testing activation

Connect voltage tester V.A.G 1527 B between contacts 1 (positive) and 2 using test cables from V.A.G 1594 A.
Start final control diagnosis and activate solenoid valves for camshaft timing control.

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

Inlet camshaft timing adjustment valve -1- -N205 and inlet camshaft timing adjustment valve -2- -N208

Connector / Contact · Test box V.A.G 1598/31 / Socket
2 · => Current flow diagrams, Electrical fault-finding and Fitting locations

Eliminate open circuit or short circuit to earth if necessary.

If the wiring is OK:

Fit a new engine control unit

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

If no fault is found:

Install a new mechanical camshaft adjuster.