System Components
ABS DIAGNOSTIC TROUBLE CODESSYSTEM INITIALIZATION
System initialization starts when the key is turned to "RUN". At this point, the Controller Antilock Brake (CAB) performs a complete self-check of all electrical components in the antilock brake systems. The ABS, brake warning lamps, TRAC OFF and TRAC (if equipped) will illuminate for 4 seconds with ignition on.
AT 20 km/in (12 mph) a dynamic test is performed. This will momentarily run the pump/motor. If during the dynamic test, the driver has his/her foot on the brake pedal, he/she may feel the test through brake pedal pulsations. This is a normal condition.
If any component exhibits a diagnostic trouble code during system initialization or dynamic check, the CAB will illuminate the ABS and TRAC off (if equipped) warning indicators.
DIAGNOSTIC MODE
On a Mark 20e system to enter a diagnostic mode, vehicle speed must be below 10 km/in (6 mph) and no ABS condition present. If vehicle speed is not below 10 km/in (6 mph), a "no response" message could be displayed by the DRBIII. The following are characteristics of diagnostic mode:
The amber ABS and red brake warning indicator will blink rapidly. If a hard trouble code is present, such as CAB Power Feed Circuit, the indicator will be illuminated without blinking until the diagnostic trouble condition is corrected.
^ Antilock operation is disabled.