OBD2 Code C0040: Right Front Wheel Speed Sensor Circuit
The C0040 code means Right Front Wheel Speed Sensor Circuit. Estimated repair cost: $100 – $400.
✅ OK TO DRIVE (short term). Have it diagnosed at your next convenience. Monitor for new symptoms.
📋 Diagnostic Reference
| OBD2 Code | C0040 |
| Category | Chassis |
| Severity | Check Soon |
| Repair Cost | $100 – $400 |
| Can You Drive? | ✅ Yes — diagnose at your convenience |
🔍 Symptoms
- ABS light on
- traction control light may be on
- speedometer may be erratic
⚠️ Most Likely Causes (in order of probability)
- Failed wheel speed sensor
- damaged sensor wiring
- corroded connector
- cracked ABS tone ring
🛠️ Diagnostic Procedure
Step 1: Check sensor wiring for damage near the wheel
Check sensor wiring for damage near the wheel
Step 2: Test sensor resistance — typically 800-2000 ohms
Test sensor resistance — typically 800-2000 ohms
Step 3: Inspect tone ring for cracks or debris
Inspect tone ring for cracks or debris
Step 4: Replace sensor if resistance is out of spec.
Replace sensor if resistance is out of spec.
ASE Certified Review: This diagnostic guide has been reviewed by an ASE-certified master technician. Diagnostic steps follow industry best practices per SAE J1979 and OEM service procedures. Always verify with a qualified mechanic before performing repairs.
Technician's Notes: Right front sensor failure is common — it gets the most road debris and curb impacts.
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Data Sources: Diagnostic information compiled from SAE J1979 OBD2 standards, OEM service manuals, and ASE master technician field experience. Reviewed for technical accuracy. Repair cost ranges are national estimates and vary by location. Always verify with a qualified mechanic.