GF32.33-D-3400H | Rear axle level control system control unit, component description | 18.9.08 |
MODEL 639
with CODE (CL0) Rear air suspension, lowerable and liftable
with CODE (C42) Stabilizer bar on rear axle
MODEL 906 with CODE (CE2) Rear air suspension
N32.33-2025-06
Illustrated on model 639
N51/3 (ELC [ENR]) control unit
Location
On model 639 the ELC control unit is located behind the side paneling on the right D-pillar.
On model 906 the ELC control unit is located (N97) in the driver seat frame.
Task
The ELC control unit receives signals from the following components via direct lines:
- Raise/lower electronic level control switch (S77/2), (with model 639 raise or lower level control switch (S77))
- Lock electronic level control switch (S77/1)
- Left rear level sensor (B22/7) and right rear level sensor (B22/10)
The ELC control unit uses the Controller Area Network bus class B (interior) (CAN-B) and receives the following messages over it:
- Vehicle speed
- Steering angle
- On-board voltage (battery voltage (G1))
- Circuit status (e.g. circuit 15)
- Vehicle variant
The ELC control unit actuates the following components after evaluating the input signals:
- Level control compressor (A9/1) with integrated air compressor motor (A9/m1) and air compressor pressure relief valve (A9/1y1)
- Level control valve unit (Y36) with both integrated left rear level control valves (Y36y1) and right rear level control valve (Y36y2)
- Electronic level control warning lamp (A1e5) in the instrument cluster (A1) and the indicator lamp in the lock electronic level control switch