Code C0670 on the 2021 Volkswagen Tiguan indicates a malfunction in the rear left ride height sensor. This sensor provides data for the headlight range control system and, if equipped, the adaptive chassis control system.
VW Ride Height Measurement
Volkswagen uses ride height sensors at the rear axle to measure vehicle loading. The data enables the headlight range control system to automatically adjust headlight aim based on passenger and cargo loading. Tiguan models with Dynamic Chassis Control (DCC) use this data for adaptive damping adjustments as well.
Symptom Identification
With C0670 present, warning lights for the headlight system or chassis control illuminate. The automatic headlight leveling function defaults to a fixed position. If equipped with DCC, the system may operate in a default mode with reduced adaptability. A message may appear in the Driver Information Display.
Diagnostic Approach
The rear left sensor mounts on the rear suspension, typically connected to a control arm via a link rod. Check the link rod connection first - this plastic or metal connector frequently breaks or disconnects. Inspect the sensor connector for VW's common green corrosion issue. Monitor live data to verify the sensor responds to suspension movement.
Repair Process
Link rod failures are the most common issue and are inexpensive to replace. Sensor failures require removing the old unit and installing a new one on the suspension. VW systems often require basic settings or calibration through VCDS or ODIS after sensor replacement to establish the reference position.