Variable Valve Timing Actuator: Testing and Inspection

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.

Recommended special tools and equipment
- VAG1526 multimeter or VAG1715 multimeter
- VAG1594 connector test kit
- Wiring diagram

Test requirements







- The respective fuses of the valves for camshaft adjustment must be OK.







- Fuses -1, 2, 3, 4 and 7- in protective housing (plenum chamber, left) must be OK.
- Battery voltage must be at least 11.5 Volts.
- All electrical consumers such as, for example, lights and rear window defroster must be switched off.
- Parking brake must be engaged or else daylight driving lights will be switched on.
- If vehicle is equipped with an A/C system, it must be switched off.
- Ground (GND) connections between engine and chassis must be OK.
- Ignition switched off.

Test sequence

Cylinder bank 1







- Disconnect 2-pin harness connector to the respective valve for camshaft adjustment:
2 Valve -1- for camshaft adjustment -N205-
3 Camshaft Adjustment Valve 1 (exhaust) -N318-

Cylinder bank 2







- Disconnect 2-pin harness connector to the respective valve for camshaft adjustment:
1 Camshaft Adjustment Valve 2 (exhaust) -N319-
3 Valve -2- for camshaft adjustment -N208-

Cylinder bank 1 and 2


NOTE:
- Cylinder bank 1 = in driving direction, right
- Cylinder bank 2 = in driving direction, left
- Before disconnecting harness connectors, mark allocation to component.


Checking resistances
- Measure resistance between terminals at connector to the respective valve for camshaft adjustment.

Specified value: 10.0...18.0 Ohms

If specified value is not obtained:
- Replace the respective control housing with the two valves for camshaft adjustment,Fig. 1.
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If specified value is obtained:

Checking wiring
- Connect test box to control module wiring harness, connect test box for wiring test. Test Box, Connecting For Wiring Test







- Check wires between test box and 2-pin connector to Engine Control Module (ECM) for open circuit according to wiring diagram.
Wire resistance: max. 1.5 Ohms

Cylinder bank 1







Cylinder bank 2

Cylinder Bank 2:

Cylinder bank 1 and 2

- Also check wires for short circuit to B+ and Ground (GND).
Specified value: Infinity Ohms







- Check wire between 1-pin connector terminal 2 and the relay carrier for open circuit according to wiring diagram.
Wire resistance: max. 1.5 Ohms

- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If no malfunctions are detected in the wires and the resistance value is OK:
- Replace Motronic Engine Control Module (ECM) -J220-.