Why does the speedometer on my first-generation Citroën C3 stop working, and at the same time, the electric power steering become “stiff” or “heavy”? Where is the sensor located?

The failure of Velocity Sensor (VSS) It is a chronic and well-documented problem in the Citroën C3 (generations with 1.4 and 1.6 engines).

• Critical Symptoms:
  1. THE The speedometer stops working. The speed on the dashboard (is set to 0 km/h).
  2. THE Electric Power Steering suddenly becomes heavier (or “hard”) at any speed.
  3. The check engine light may come on, or intermittent transmission failures may occur (in the case of the AL4 automatic transmission).
• Causal Relationship: The C3’s electric power steering is progressiveIn other words, it is programmed to be… lighter at low speed (for maneuvering) and firmer/heavier at high speed (for stability). The electric power steering module (DPA) obtains the car’s speed information through the Velocity Sensor (VSS)which sends the pulse to the ECU module.
  • When the VSS fails, the car interprets that it is stopped (0 km/h). For safety reasons, the steering enters a failsafe mode and assumes a fixed behavior, usually remaining… heavy, simulating high-speed driving.
• Location and Solution: THE Speed ​​Sensor It is located in Gearbox (usually located above, near the constant velocity joint or the tulip joint). The solution involves replacing the sensor and, in some cases, checking the plastic gear (pinion) inside the transmission that activates the sensor. In simpler cases, the fault may simply be the fuse F01 (typically 10A) in the BSM, which protects the sensor line.