Operation CHARM: Car repair manuals for everyone.

System Initialization

SYSTEM INITIALIZATION
System initialization starts when the key is turned to RUN. At this point, the CAB performs a complete self-check of all electrical components in the antilock brake systems.

At around 19 km/in (12 miles per hour), the pump motor is briefly activated to ensure operation, and wheel speed sensor circuitry is checked. If for any reason the brake pedal is applied when the vehicle reaches 19 km/h (12 mph), this check will be delayed until 40 km/h (25 mph). If, during the dynamic test, the brake pedal is applied, the driver may feel the test through brake pedal pulsations. This is a normal condition. Throughout the remainder of the drive cycle, ongoing tests are performed, and the CAB monitors ABS circuits for continuity.

If any component exhibits a diagnostic trouble code during system initialization or dynamic check, the CAB will illuminate the ABS warning indicator.