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C0121 — Valve Relay Circuit

ABS valve relay circuit fault.

Severity: HighRepair: $50-$1,500Difficulty: Advanced

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Common symptoms of C0121

Common causes of C0121

Repair cost & difficulty

Typical cost to fix C0121: $50-$1,500 · Difficulty: Advanced

Pro tip: On GM, C0121 often indicates ABS module internal relay failure. Module usually needs replacement or rebuild.

Vehicles commonly affected

GM — common GM ABS code

Related trouble codes

C0110C0060

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ScanFixAI is a diagnostic aid, not a substitute for professional repair. Cost estimates are typical ranges and vary by vehicle and region.