Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Removing and installing/replacing servomotor for eccentric shaft (N55T0 Engine) (2016-2018)
The eccentric shaft may only be twisted on the mounting flats for protection.
Risk of damage to the eccentric shaft gearing and to the servomotor worm drive.
The eccentric shaft must not spring back to the minimum stroke stop. Risk of damage!
Necessary preliminary tasks:
- Remove CYLINDER HEAD COVER .
- Remove IGNITION COILS AND INJECTOR SHAFTS of cylinders 1 to 4.
The eccentric shaft on the mounting flats (2) must only be turned with an open-end spanner (1) for support.
Heed the following work instructions.
After the motor stops, the eccentric shaft is in the maximum stroke position.
If the actuator drive is defective, the eccentric shaft is located in an undetermined position.
Release bolt (1) on the oil spray nozzle.
Tightening torque: 11 37 4AZ .
Unclip oil spray nozzle (2) from the bracket on the actuator drive (3) in direction of arrow.
If the eccentric shaft is not on maximum stroke, the eccentric shaft must be adjusted to maximum stroke.
Adjust eccentric shaft only on the hexagon socket of the actuator drive (preload).
Remove minimum stroke stop (1).
Turn 4-mm hexagon socket wrench (1) clockwise in direction of arrow (maximum stroke).
Secure eccentric shaft with an open-end spanner (2) for support in direction of arrow.
Fix eccentric shaft with an open-end spanner (2) (kickback danger)
Remove minimum stroke stop (1).
Tightening torque: 11 37 5AZ .
Adjust eccentric shaft (1) to minimum stroke in direction of arrow via servomotor.
Slowly adjust eccentric shaft in direction of arrow to minimum stroke via the servomotor with a 4-mm hexagon socket wrench (2) and an open-end spanner (1).
Release gearing of the eccentric shaft from worm drive.
Turn eccentric shaft (2) approximately 90° further with an open-end spanner (1).
Secure eccentric shaft (2) against kickback with the assistance of a second person.
Secure eccentric shaft (1) against kickback with the assistance of a second person.
Unfasten screws (2).
Remove servomotor (1) upward in direction of arrow.
Installation note:
Clean blind holes with compressed air.
Install servomotor (1) downward in direction of arrow.
Secure eccentric shaft against kickback with the assistance of a second person.
Installation note:
The gearing of the eccentric shaft and the WORM GEAR MUST BE GREASED WITH LONGTIME PD 1 (4.1) .
Installation note:
Eccentric shaft and worm drive must now be joined.
Carefully mate eccentric shaft gear in the worm shaft of the servomotor by simultaneously pressing and turning on the actuator drive.
Insert bolts (2).
Tightening torque: 11 37 3AZ .
Preload eccentric shaft to maximum stroke with a 4mm hexagon socket wrench (1) on the servomotor in direction of arrow.
Fix eccentric shaft with an open-end spanner (2) for support and secure (kickback danger).
Adjust eccentric shaft (1) back to maximum stroke in direction of arrow via servomotor.
Screw in stop (1) for minimum stroke.
Tightening torque: 11 37 5AZ .
Retract oil spray nozzle (2) on actuator drive (3).
Engage bolt (1) and release back to 90°.
For exact positioning of the oil spray nozzle (2) audibly clip it in at the top.
Secure oil spray nozzle (2) with screw (1).
Tightening torque: 11 37 4AZ .
Remove all special tools.
Assemble engine.
Check function of Digital Engine Electronics.
- Service function.
- Drive.
- Digital Motor Electronics
- Valvetronic run-in procedure.
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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