Front Suspension

Vehicle level sensor





Vehicles with gas-discharge headlights or air suspension have an automatic vertical aim control system as standard equipment.

To function properly, the automatic vertical aim control system needs information about compression travel or rebound travel at front and rear axles.

For this, the position of lower left control arm relative to body is transferred to left front level control system sensor -G78- via a coupling rod. This sensor passes on electrical signals to control module for vertical aim control system.

On the rear axle these signals are passed on from the vehicle level sensor -G76- to the control module.

For 4 wheel air suspension, 4 sensors are required (total).

These signals are needed to determine the vehicle level.

The headlight vertical aim control reacts automatically to changes in the vehicle level.

The vehicle level can change in the following situations:
^ Operating with something in tow
^ Various loading conditions; vehicle empty, vehicle partially or completely loaded;
^ Driving slowly or quickly.

CAUTION: Check adjustment of headlights!

Note: It is always necessary to check the basic setting of the headlights whenever:
^ The link has been removed and reinstalled or replaced

Note:
^ Installation work has been performed on the vehicle level sensor,
^ The vehicle level sensor has been replaced;
^ The retaining clip for coupling rod on link has been loosened.

Basic setting of the headlights

1. Bracket
2. Left Front Level Control System Sensor -G78-
^ Checked electrically via On Board Diagnostic (OBD)
^ For problems/complaints
3. Socket head bolt, 10 Nm
4. Rivet
5. Self-locking nut, 10 Nm
^ Always replace after disassembly
6. Suspension strut
7. Coupling for stabilizer bar
8. Actuating arm of Left Front Level Control System Sensor -G78-
^ Do not remove coupling link from ball head!
^ Coupling rods must not be swapped for Allroad
9. Position marks on control arm for installation position of left front level control system sensor G78-
10. Front link, lower
11. Clip
^ Pry out with a slotted-head screwdriver, for example

When removing and reinstalling track control link it is necessary to remove metal clip.

Note: When installing linkage to the level sensor, use a 10 mm open-end wrench with dimension -A- = 4 mm to avoid damaging the seal.





^ Dimension -A- 4 mm
^ Wheel bolt tightening torque: 120 Nm
^ The linkage for the headlight vertical aim control is fastened to the track control link between the stops using pliers.
When installing headlight vertical aim control, make sure that the sensor crank and linkage are in correct orientation to one another.

Note:
^ Linkage must be vertical.
^ The crank sensor (arm) must point forward and downward.
^ Coupling rods must not be swapped with each other for Allroad.

Level sensor in Installation position - Allroad





The 4 level control system sensors -G76-, -G77-, -G78- and -G289- on the Audi Allroad are identical, only the brackets and coupling rods - kinematic is side - and axle specific.

Note the different color of coupling rods at front axle.

If level sensor is replaced, or a connection is loosened, basic setting must be performed