Which of the following is the least likely cause of an intermittent problem in an ABS system?

An intermittent problem in an ABS (Anti-lock Braking System) can often be linked to issues that affect the system's ability to communicate effectively or function properly at various times. The least likely cause of such a problem among the given options is related to worn brake pads.

Worn brake pads primarily affect braking performance and may not directly interfere with the operation of the ABS system itself. While they can cause noise and reduced braking efficiency, they do not typically produce intermittent faults in the ABS, as the system's primary function revolves around modulating braking force during hard stops to prevent wheel lockup. The condition of the brake pads is generally consistent, and while worn pads are a concern for overall braking efficacy, they wouldn't lead to unpredictable behavior in the ABS operation.

On the other hand, issues like a faulty brake pedal sensor, water contamination in the brake fluid, or an open wheel sensor circuit can create irregularities in how the ABS engages or communicates with other components in the braking system. Consequently, they are more likely to generate intermittent problems due to their direct impact on the system’s functionality or electrical signals.