SYSTEM SELF TEST
The RABS module performs system tests and self-tests during start up 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.To obtain the flash code:
Locate the RABS diagnostic connector (orange/black wire) and attach a jumper wire to it and ground it to the chassis.
Quickly remove the ground. When the ground is made and then removed, the RABS light will begin to flash.
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: three short and one long flash indicates a Code 4. The code will continue until the ignition is turned OFF.
Diagnostic code 2-Open isolate circuit
Diagnostic code 3-Open dump circuit
Diagnostic code 4-RABS Valve switch closed or open dump valve
Diagnostic code 5-System dumps too many times in 2WD )2WD and 4WD vehicles), condition occurs while making normal or hard stops. Rear brake may lock.
Diagnostic code 6-Sensor signal rapidly cuts in and out, condition only occurs while driving
Diagnostic code 7-No isolate valve self test
Diagnostic code 8-No dump valve self test
Diagnostic code 9-High sensor resistance
Diagnostic code 10-Low sensor resistance
Diagnostic code 11-Stop lamp switch circuit defective, condition indicated only when driving above 35 mph (56 km/h)
Diagnostic code 12-Low brake fluid level detected during anti-lock stop
Diagnostic code 13-Speed processor check
Diagnostic code 14-Program check
Diagnostic code 15-Memory failure
Diagnostic code 16-16 or more flashes should not occur
DIAGNOSTIC FLOW CHARTS
The following pages contain diagnostic charts which may be used to help narrow a RABS component or system failure.
See Figures 1 through 12
Fig. Fig. 1: Yellow ANTILOCK Light Off and Does Not Self-Check: Test A
Fig. Fig. 2: Yellow ANTILOCK Light Off and Does Not Self-Check: Test A - Cont'd
Fig. Fig. 3: Red BRAKE Light On, Yellow ANTILOCK Light Off, and ANTILOCK Light Does Self-Check: Test B
Fig. Fig. 4: Yellow ANTILOCK Light On and Red BRAKE Light On: Test C
Fig. Fig. 5: Yellow ANTILOCK Light On and Red BRAKE Light On: Test C - Cont'd
Fig. Fig. 6: Yellow ANTILOCK Light On, Red BRAKE Light Off: Test D
Fig. Fig. 7: Yellow ANTIILOCK Light On Red BRAKE Light Off (Cont'd): Test D
Fig. Fig. 8: Yellow ANTILOCK Light On, Red BRAKE Light Off: Test D
Fig. Fig. 9: Yellow Antilock Light Flashing, Red Brake Light Off - Test E
Fig. Fig. 10: Rear Wheels Lock with Hard Stops - Both Lamps functioning Properly: Test F
Fig. Fig. 11: Rar Wheels Lock with Hard Stops - both Lamps Functioning Properly (Continued): Test F
Fig. Fig. 12: Yellow Anti-Lock Light Self Checks, Red Brake Light Does Not Self Check: Test G