di_a166
Moderate
Tesla · Sedans
Cruise control disabled - speed sensor fault
Quick Answer
Error code DI_a166 on your Tesla Sedans means: Cruise control disabled - speed sensor fault. This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
T3T3HT3PTSTSLRTSP
Likely Causes
  1. Speed sensor wiring disconnected or corroded
  2. Wheel speed sensor bearing failure or misalignment
  3. Radar unit signal interference or malfunction
  4. Vehicle control module loss of sensor communication
  5. Damaged speed sensor connector pin or housing
How to Fix It
1
Inspect wheel speed sensor connectors at each wheel for corrosion
2
Check for visible damage to speed sensor wiring harness
3
Clean radar sensor dome of dirt, snow, or ice buildup
4
Perform system reset by cycling vehicle power multiple times
5
If unresolved, schedule service for speed sensor replacement or radar module calibration
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Speed sensor replacement kit
Connector repair kit with dielectric grease
Radar alignment and calibration tool
Related Error Codes
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