C0205 moderate

Front Wheel Speed Sensor Mismatch

The C0205 code means the vehicle's onboard diagnostic system has detected: Front Wheel Speed Sensor Mismatch. This is a moderate severity code.

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Keep driving?: Short distances only
DIY difficulty: moderate
Estimated cost: $50 - $400 (parts and labor)

Read ABS Codes

BlueDriver Bluetooth Pro Scanner

Basic scanners cannot read ABS codes. BlueDriver reads all systems including ABS, SRS, and transmission through your phone.

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Read ABS Codes

LAUNCH CRP123X (Reads ABS + Chassis)

Basic scanners cannot read ABS codes. This one reads all four systems so you know exactly which sensor failed.

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Common Symptoms

ABS warning light on
Traction control light on
Stability control disabled
False ABS activation during normal driving
Speedometer fluctuation

Probable Causes (Ranked by Likelihood)

One front wheel speed sensor failing or producing erratic signal Very High
Mismatched tire sizes between front wheels High
Tone ring damage on one front wheel Moderate
Front wheel bearing play on one side Moderate
ABS module misinterpreting sensor data Low

Step-by-Step Diagnostic Procedure

Compare left and right front wheel speed readings in live data during straight driving
Verify front tires are the same size and brand with similar tread depth
Inspect both front tone rings for damage
Check both front wheel bearings for play
Clean both front wheel speed sensors and check air gaps

Frequently Asked Questions

Can different tire sizes cause a wheel speed mismatch code?

Yes. Even a small difference in tire diameter between the left and right front wheels causes them to rotate at slightly different speeds, which the ABS module interprets as a sensor mismatch.

How much tire size difference causes this code?

A difference of more than 3-5% in rolling circumference can trigger mismatch codes. This can occur with significantly different tread depth, different tire brands, or a mismatched spare tire.

Should I replace both sensors if only one is bad?

It is not strictly necessary, but replacing both at the same time is often recommended since they are inexpensive and age at the same rate. This prevents a repeat visit when the other one fails shortly after.