Ford Full-Size Vans 1989-1996 Repair Guide

System Self-Test


See Figure 1

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Fig. Fig. 1: RABS trouble code index

The RABS module performs system tests and self-tests during startup and normal operation. The valve, sensor and fluid level circuits are monitored for proper operation. If a fault is found, the RABS will be deactivated and the REAR ANTI LOCK light will be lit until the ignition is turned OFF. When the light is lit, the diagnostic flashout code may be obtained. Under normal operation, the light will stay on for about 2 seconds while the ignition switch is in the ON position and will go out shortly after. A flash code may be obtained only when the yellow light is ON. Before reading the code, drive the vehicle to a level area and place the shift lever in the PARK or NEUTRAL position. Keep the vehicle ignition ON.

Starting in 1993, all vehicles use the RABS II system. The major difference between the two systems is the addition of a "keep alive memory" (codes are stored, even if ignition is turned off), and a code 16 can be set, which means the system is operating properly.

  1. Locate the RABS diagnostic connector (orange/black wire) and attach a jumper wire to it and momentarily (1 to 2 seconds) ground it to the chassis.
  3. Quickly remove the ground. When the ground is made and then removed, the RABS light will begin to flash.
  5. The code consists of a number of short flashes and ends with a long flash. Count the short flashes and include the following long flash in the count to obtain the code number. Example 3 short flashes and one long flash indicated Code No. 4. The code will continue until the ignition is turned OFF . Refer to the flashcode diagnosis charts for further instructions.