CDL General Knowledge TestDriving SafelyMedium

A commercial driver notices that their vehicle's ABS malfunction light remains illuminated after the initial system check. What does this indicate, and what should be the driver's course of action?

  1. AThe ABS system is functioning normally; the light will turn off after driving a short distance.
  2. BThe entire braking system has failed, and the vehicle should not be driven under any circumstances.
  3. CThe ABS system has a malfunction, but the regular brakes are still operational. Drive carefully to a repair facility.
  4. DThe ABS system is temporarily disabled due to moisture, and it will reactivate once the vehicle dries out.
Show answer & explanation

Correct answer: C. The ABS system has a malfunction, but the regular brakes are still operational. Drive carefully to a repair facility.

An illuminated ABS malfunction light indicates that the Anti-lock Braking System is not working correctly. However, the regular braking system (service brakes) should still be fully functional. The vehicle is safe to drive with caution to a repair facility to address the ABS issue.

Why the other options are wrong

  • A. An illuminated malfunction light indicates a fault, not normal operation.
  • B. ABS failure does not mean the entire braking system has failed; only the anti-lock feature is compromised.
  • D. ABS malfunctions are typically electrical or mechanical, not usually temporary due to moisture.

ABS Malfunction Light

An indicator light on the dashboard that illuminates when the Anti-lock Braking System (ABS) detects a fault, signaling that the ABS feature is not operational.

  • Indicates ABS failure, not total brake failure.
  • Regular brakes (service brakes) still function.
  • Requires inspection and repair, but vehicle can be driven cautiously.

Memory trick: ABS light on, regular brakes still strong!

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