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Home >> Toyota >> 2000 >> 4Runner Base, 4WD >> Repair and Diagnosis >> Brakes >> Traction Control >> Anti-Lock Brake System >> Circuit Tests >> Abs Warning Light Circuit >> Diagnostic Procedure

Diagnostic Procedure

  1. If ABS warning light remains illuminated, go to step  3. If ABS warning light does not illuminate, check light bulb and replace as necessary. If bulb is okay, diagnose combination meter. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. If combination meter is okay, go to next step.
  2. Turn ignition off. Disconnect ABS control relay. Using DVOM, check for continuity between specified relay terminals. See ABS CONTROL (MOTOR & SOLENOID) RELAY INSPECTION  table. Replace relay if continuity is not as specified. If relay is okay, check for open in wiring harness between DLC1, ABS control relay and chassis ground. See WIRING DIAGRAMS. Repair as necessary.
  3. Retrieve DTCs. See RETRIEVING DTCS  under SELF-DIAGNOSTICS. If DTC is present, perform appropriate test under DIAGNOSTIC TESTS. If DTC is not present, go to next step.
  4. Remove short pin from DLC1. If ABS warning light turns off, go to next step. If ABS warning light does not turn off, check for short in wiring harness between ABS warning light, DLC1 and ABS ECU. See WIRING DIAGRAMS . Repair as necessary.
  5. Check ABS control relay. Go to step  2. Replace as necessary. If relay is okay, check for short in wiring harness between DLC1 and ABS control relay. See WIRING DIAGRAMS . Repair as necessary.
ABS CONTROL (MOTOR & SOLENOID) RELAY INSPECTION

Condition (1) Terminals Specification
De-Energized A7-1 & A6-3 80 Ohms
A7-5 & A7-6 Continuity
A7-2 & A7-5 Open
A7-4 & A7-5 (2) Continuity
Energized (3) A7-5 & A7-6 Open
A7-2 & A7-5 Continuity
(1) For terminal identification, see WIRING DIAGRAMS .
(2) Relay contains a diode. Continuity should only be present when connecting positive test lead to terminal A7-4, and negative test lead to terminal A7-5.
(3) Battery voltage applied across relay terminals A7-1 and A6-3.