U0421

Invalid Data Received From Suspension Control Module A

OBD-II diagnostic trouble code U0421indicates a fault detected by the vehicle's onboard computer. This code applies to all OBD-II compliant vehicles and should be addressed promptly to avoid potential engine or emissions system damage.

Severity Level 4 — Serious

This code indicates a serious issue that can cause noticeable driveability problems and potential engine damage if not addressed. The vehicle should be taken to a mechanic as soon as possible. Extended driving is not recommended.

Common Symptoms

• Multiple warning lights
• Gauges may not work
• Vehicle may not start

Possible Causes

• Invalid Data Received From Suspension Control Module A
• Fault in related component or circuit

Common Fixes

• Scan with OBD2 diagnostic tool
• Inspect related components and wiring

Estimated Repair Cost

These are estimated costs based on generic repair data. Actual costs may vary depending on your vehicle, location, and labor rates.

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