C0040
Medium SeverityRight Front Wheel Speed Sensor Circuit
Chassis/Brakes System
C0040 — Instant Answer
Right Front Wheel Speed Sensor Circuit
Severity: MEDIUM SEVERITY
Meaning: ABS lost signal from the right front wheel speed sensor.
Safe to drive? Usually yes with caution, but confirm root cause before long trips.
Estimated repair cost: $20 - $60
Most common causes:
- 1. Failed sensor (35-45% of cases)
- 2. Damaged wiring (35-45% of cases)
- 3. Dirty sensor (10-25% of cases)
Symptoms
- ⚠️ABS light on
- ⚠️Traction control disabled
- ⚠️Stability control off
Common Causes
How to Diagnose C0040
- 1Inspect sensor and wiring
- 2Clean sensor
- 3Replace if damaged
OEM Diagnostic Flowchart
Scroll to load technician if/then branches.
C0040 requires a scanner that reads chassis modules — basic code readers won't see it.
ArtiLink600
$99
DIYers working on ABS/airbag systems
View on TOPDON
ArtiDiag900 Lite
$299.24
Serious DIYers and side-hustle mechanics
View on TOPDONGot a repair estimate for C0040? Check if the quote is fair before ordering parts.
Turn This Into a Confident Next Step
Verify the likely fault first, then compare a quote before you approve expensive work.
Affiliate disclosure: We may earn a commission at no extra cost to you.
View supporting tool options
OBD2 scanner
Read codes and freeze-frame data before you guess at the fault.
Most diagnostic jobs start with a scan tool and a verified code path.
Shop on Amazon →Battery tester
Check cranking and charging health before replacing expensive parts.
A weak battery can mimic alternator or starter problems.
Shop on Amazon →Multimeter kit
Confirm voltage, continuity, and sensor power with one simple kit.
A meter is the cheapest way to rule out a bad circuit fast.
Shop on Amazon →Related Codes
Frequently Asked Questions
- Are wheel speed sensors easy to replace?
- Usually yes — they bolt to the wheel hub or knuckle. One bolt and one connector.
- Can a bad wheel bearing cause this?
- Yes — a worn wheel bearing can cause the tone ring to wobble, giving erratic speed sensor readings.
Get the Complete Maintenance Schedule for C0040 drivers
Oil, filters, belts, brakes, and fluid intervals sent to your inbox. Unsubscribe anytime.
Not sure you want to DIY? Compare local shop pricing first.
Author & Review
Written by AllOEMManuals Editorial Team. Reviewed by ASE-certified technicians and updated with factory-reference checks for fitment-sensitive steps.
This guide was drafted with AI assistance and reviewed for accuracy by a human editor.
Last updated: 2026-05-07