C0030 concerns the tone wheel (encoder ring) at the left front wheel, whose teeth or magnetic poles the wheel speed sensor reads. A cracked, dirty or missing segment produces a signal pattern the ABS module recognises as faulty. Without a plausible wheel speed the module switches off ABS and stability control for the rest of the drive. The code is a general fault for this component; the module stores it when the signal or circuit fails a check that no more specific code covers.
Medium severity. Can I keep driving?Drive with caution and go to a repair shop. If it affects the brakes or steering, do not continue if you notice abnormal behavior.
Symptoms
- ABS, ESC or brake warning light on
- Stability and traction control may be switched off
Most likely causes
- Cracked or damaged tone wheel
- Metal debris or rust on the encoder
- Wrong hub or bearing with different encoder fitted
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
What each character of C0030 means
- C: Chassis
- 0: Generic code: same on every make
- 0: Subsystem depends on the code range
- 30: Specific fault in that system
Frequently asked questions
Can I keep driving with code C0030?
Drive with caution and go to a repair shop. If it affects the brakes or steering, do not continue if you notice abnormal behavior.
What causes code C0030?
The most common causes are: cracked or damaged tone wheel; metal debris or rust on the encoder; wrong hub or bearing with different encoder fitted.
Related codes
- C0037Left Rear Wheel Speed Sensor
- C0038Left Rear Wheel Speed Sensor Supply
- C0039Right Rear Tone Wheel
- C003ARight Rear Wheel Speed Sensor
- C003BRight Rear Wheel Speed Sensor Supply
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.