What does it mean?
C1950 is a Chassis (ABS, traction control, steering) fault code. It indicates: Combined Sensor (Forward G-Sensor) .
Symptoms
- Stability, traction and ABS warning lamps on with the systems switched off
- Hill start assist and hill descent control unavailable
- Braking behaviour feels different in hard stops as brake force distribution strategies default
- Unexpected stability intervention while braking or accelerating in a straight line
- Code setting again shortly after every engine start
Likely causes
- Internal failure of the longitudinal acceleration element within the combined sensor
- Zero point calibration not carried out after replacing the sensor, the module or working on the suspension
- Loose mounting bolts or a cracked bracket letting the sensor read body vibration as acceleration
- Sensor refitted at the wrong angle or not level, so its reference is wrong
- Open circuit, short or high resistance on the sensor supply, ground or data line
- Water or corrosion at the sensor connector under the console, carpet or seat
- Low battery voltage, or a fault in the ABS/ESP module that interprets the value
How to fix it
- With the vehicle stationary on level ground, read the forward/longitudinal G value; it should sit near zero
- Apply the brakes gently on a road test and check the value rises and falls smoothly instead of staying frozen
- Check the sensor mounting: bolts tight, bracket undamaged and the sensor sitting flat at the correct angle
- Inspect the connector for water and corrosion, and confirm supply voltage and ground quality
- Verify the data line between the sensor and the ABS/ESP module
- Run the zero point calibration procedure on level ground
- Replace the combined sensor if the value stays out of range or frozen with a good circuit, then calibrate again and road test