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.
11 37... Fault patterns, valve gear (N20/26/N55)
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. See 11 12 000 REMOVING AND INSTALLING/SEALING CYLINDER HEAD COVER (N55) .
- Remove ignition coil and injector shafts. See 11 12 040 REMOVING AND INSTALLING ALL IGNITION COILS AND INJECTOR WELLS (N55) .
The eccentric shaft on the mounting flats (2) must only be turned with an open-end spanner (1) for support.
The eccentric shaft has mounting flats on both sides ; if the engine is installed, the front mounting flat must be used.
Heed the following work instructions.
After the engine 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.
Check throttle return spring (2) for breakage and correct installation position on intermediate lever (1).
Check roller cam follower (3) for correct installation position.
Check that intermediate lever (1) is correctly seated.
NO RELATED
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.