Variable Valve Timing Actuator: Testing and Inspection

Diagnostic Procedures



Camshaft Adjustment Valves, Checking

Function

The camshaft adjustment is load- and RPM dependent. The electrical valves for camshaft adjustment switch oil pressure onto camshaft adjusters (mechanical adjustment mechanisms), which then adjust the camshafts.

Special tools, testers and auxiliary items required

• Hand multimeter (V.A.G 1526) or Multimeter (V.A.G 1715)

• Test adapter kit (V.A.G 1594)

• Wiring diagram

Test Conditions

• Motronic Engine Control Module (ECM) Power Supply Relay (J271) -position 4- must be OK, check:

• The Ground (GND) connections between engine and body must be OK.

• Ignition switched off.

• Fuses in right instrument panel fuse holder must be OK:

Right instrument panel fuse holder





Test Sequence

Cylinder bank 1

- Disconnect corresponding 2-pin harness connector from respective valve for camshaft adjustment:





2 Camshaft Adjustment Valve 1 (N205) - 1 -
3 Camshaft Adjustment Valve 1 (exhaust) (N318) - 1 -

Cylinder bank 2

- Disconnect corresponding 2-pin harness connector from the respective valve for camshaft adjustment:





2 Camshaft Adjustment Valve 2 (exhaust) (N319) - 2 -
3 Camshaft Adjustment Valve 2 (N208) - 2 -

Cylinder bank 1 and 2

• Before disconnecting harness connectors, mark allocation to component.

• Cylinder bank 1 with cylinders 1 through 6 is located at right in direction of travel.

• Cylinder bank 2 with cylinders 7 through 12 is located at left in direction of travel.

Checking resistances

- Check resistance between terminals at connector to respective valve for camshaft adjustment. Specification: 10.0 to 18.0 ohms

If specification is not obtained:

- Replace respective control housing with both camshaft adjustment valves.

- Erase DTC memory of Engine Control Module => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09, Diagnostic mode 4: Reset/erase diagnostic data.

- Generate readiness code => [ Readiness Code, Generating ] Monitors, Trips, Drive Cycles and Readiness Codes.

If specification is obtained:

- Check wires to Engine Control Module according to wiring diagram.

1Checking wires to Engine Control Module (ECM)

Cylinder bank 1

- Connect test box to Engine Control Module (ECM) (J623) wiring harness on connecting test box for wiring test, refer to Repair Manual,

Cylinder bank 2

- Connect test box to Engine Control Module (ECM) 2 (J624) wiring harness on connecting test box for wiring test.

Cylinder bank 1 and 2

- Check wires between test box and 2-pin connector to Engine Control Module for open circuit according to wiring diagram. Wiring resistance: max. 1.5 ohms





Cylinder bank 1





Cylinder bank 2





Cylinder bank 1 and 2

- Check the wire for short circuit to B+ and Ground (GND). Specification: infinite ohms

- Check wire between 1-pin connector terminal 2 and Motronic Engine Control Module (ECM) Power Supply Relay (J271) for open circuit according to wiring diagram. Wiring resistance: max. 1.5 ohms

- Erase DTC memory of Engine Control Module => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09, Diagnostic mode 4: Reset/erase diagnostic data.

- Generate readiness code => [ Readiness Code, Generating ] Monitors, Trips, Drive Cycles and Readiness Codes.

If no malfunctions are detected in the wires and the resistance value is OK:

Cylinder bank 1

- Replace Engine Control Module (ECM) (J623)l.

Cylinder bank 2

- Replace Engine Control Module (ECM) 2 (J624).