Variable Valve Timing Solenoid: Testing and Inspection
Solenoid valves for camshaft adjustment, testing
Special tools and equipment
^ V.A.G 1526 A
^ V.A.G 1527 B
^ V.A.G 1594 A
^ V.A.G 1598/31
^ VAS 5051 with VAS 5051/1
- Connect vehicle diagnostic, test and information system VAS 5051 and select vehicle system "01 - Engine electronics". When doing this, ignition must be on.
Display on VAS 5051
- Select diagnosis function "03 - Final control diagnosis" from menu -1-
- Press the (arrow) button repeatedly until following display appears:
Display on VAS 5051:
A - Actuator test is waiting Continued switching required
5 - Bank 2, camshaft timing control go to -N208-
- Press the (arrow) button.
Display on VAS 5051:
A - Actuator is running - Continued switching allowed
- The solenoid valve for camshaft adjustment on bank 2 (left) is activated at intervals for about 1 minute (and should click audibly) unless test program is deliberately advanced to next control element by pressing the (arrow) button.
- Press the (arrow) button repeatedly until following display appears:
Display on VAS 5051
A - Actuator test is waiting Continued switching required
9 - Bank 1, camshaft timing control go to -N205-
- Press the (arrow) button.
Display on VAS 5051:
A - Actuator is running - Continued switching allowed
- The solenoid valve for camshaft adjustment on bank 1 (right) is activated at intervals for about 1 minute (and should click audibly) unless test program is deliberately advanced to next control element by pressing the (arrow) button.
- Press the A button to exit from function "03 - Final control diagnosis".
- Switch ignition off.
If one of the valves is not activated (does not click):
Electrical test of solenoid valves for camshaft adjustment
- To test solenoid valve on left cylinder bank, open fasteners -1- and -2- and pull off engine cover panel from above (arrows).
- To test solenoid valve on right cylinder bank, also remove air filter housing.
Testing internal resistance
- Unplug electrical connector on relevant valve (arrow).
- Connect multimeter to valve (resistance measurement range)
^ Specification: 10 to 18 Ohms
If specification is not attained:
- Install anew valve.
If specification is obtained:
Checking voltage supply
Requirements for test:
^ Fuse for solenoid valves for camshaft timing control OK
^ Fuel pump relay OK
Note: The solenoid valves for camshaft timing control receive their power supply via fuel pump relay.
Part 1:
Part 2:
- Connect voltage tester V.A.G 1527 B as follows:
- Operate starter briefly.
^ The LED should light up.
If LED does not light up:
- Test for open circuit in wiring connection between fuel pump relay and contact 1 on connector via fuse (refer to wiring diagram).
- Eliminate open circuit in wiring (refer to wiring diagram).
If LED lights up:
Checking activation
- Connect voltage tester V.A.G 1527 B to contact 1 (positive) and contact 2 of connector.
- Vehicle diagnostic, testing and information system VAS 5051 is connected; vehicle system "01 - Engine electronics" is selected. Ignition must be switched on.
Display on VAS 5051:
- Select diagnosis function "03 - Final control diagnosis" from menu -1-
- Press the (arrow) button repeatedly until following display appears:
Display on VAS 5051:
A - Actuator test is waiting - Continued switching required
5 - Bank 2, camshaft timing control go to -N208
- Press the (arrow) button.
Display on VAS 5051:
A - Actuator is running Continued switching allowed
^ The LED should flash.
- Press the (arrow) button repeatedly until following display appears:
Display on VAS 5051
A - Actuator test is waiting Continued switching required
9 - Bank 1, camshaft timing control go to -N205
- Press the (arrow) button.
Display on VAS 5051:
A - Actuator is running Continued switching allowed
^ The LED should flash.
- Press the (arrow) button to exit from function "03 - Final control diagnosis".
- Switch off ignition.
If LED lamp does not flash or if it lights up continuously:
- Connect test box V.A.G 1598/31 to connectors on wiring harness (engine control unit remains disconnected). Also connect ground clamp of test box to battery negative terminal (not shown in illustration).
WARNING:
- To prevent damage to electronic components, switch to respective measuring range before connecting measuring cable and observe test prerequisites.
- Test for open circuit and short to positive or ground in following wiring connections:
Valve -1- for camshaft adjustment -N205- or Valve -2- for camshaft adjustment -N208-.
- Eliminate open circuit or short circuit using wiring diagram.
If wiring is OK
- Install a new engine control unit:
If no fault is found:
- Install a new mechanical camshaft adjuster.
- Install air filter housing.