How do you test the performance of an ABS system during a road/slow-speed test?

• A. Apply firm, controlled braking on a dry surface to feel pedal pulsation and confirm proper skid control; observe dash ABS indicator and retrieve any fault codes with a scan tool.
• B. Observe dash ABS indicator and retrieve any fault codes with a scan tool only.
• C. Apply firm, controlled braking on a dry surface to feel pedal pulsation, observe dash ABS indicator, and retrieve fault codes with a scan tool.
• D. Disable ABS and test standard braking only.

Answer: (C)

Testing ABS performance during a road/slow-speed run relies on three coordinated checks that together confirm the system is working as intended. First, apply firm, controlled braking on a dry surface to provoke the ABS cycling and feel for the pedal pulsation. The brake pedal should rhythmically pulse as the hydraulic modulator rapidly applies and releases pressure to prevent wheel lock. This pedal feel is a direct indicator that the ABS is engaging and modulating brake pressure.

Second, observe the dash ABS indicator. A proper test expects normal operation with no abnormal light staying on, and a flashing indicator can indicate active modulation during braking. A persistent or abnormal illumination signals a fault in the system that needs attention, even if you felt pulsation.

Third, retrieve fault codes with a scan tool. Scanning catches stored or current faults in wheel speed sensors, wiring, the hydraulic pump/valves, or the control module that might not be evident from pedal feel or the indicator alone. This helps pinpoint specific components that may be failing.

Relying on just one aspect—pedal pulsation, or indicator status, or codes—can miss hidden faults. Testing all three parts together gives a complete picture of ABS health. Disabling ABS would prevent this evaluation and is not appropriate for testing performance.