ABS Warning Light Remains ON: Procedure

1. Check that each ECU connector is properly installed.

   OK

   Each ECU connector is properly installed.

NG → CONNECT CONNECTOR TO ECU CORRECTLY 

OK: Go to next step 

1. Check the battery voltage.

   Standard voltage

   11 to 14 V

NG → RECHARGE OR REPLACE BATTERY 

OK: Go to next step 

1. Check for DTC. Refer to DTC CHECK / CLEAR .
   RESULT
   
   

   Result	Proceed to
   Warning light remains on (when using Techstream)	A
   Warning light remains on (DTC cannot be output) (when not using Techstream)	B
   Malfunction code is output	C
   Normal code is output (when not using Techstream)	D

D → END 

C → REPAIR CIRCUITS INDICATED BY OUTPUT DTCS 

B → See step   5 

A: Go to next step 

1. Check the Data List for proper functioning of the IG voltage.
   ABS/VSC/TRAC
   
   

   Tester Display	Measurement Item / Range	Normal Condition	Diagnostic Note
   ECU IG Power Voltage	ECU power supply voltage / LOW/NORMAL/HIGH	LOW: Below 10 V NORMAL: 10 to 14 V HIGH: 14 V or more	-

   RESULT
   
   

   Result	Proceed to
   Display is not NORMAL	A
   Display is NORMAL	B

B → REPLACE SKID CONTROL ECU 

A: Go to next step 

Fig 1: Checking Wire Harness (Skid Control ECU - Battery And Body Ground)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the S5, S7 and S8 ECU connectors.
2. Turn the ignition switch ON.
3. Measure the voltage of the wire harness side connectors.

   Standard voltage

   Tester Connection	Specified Condition
   S7-6 (IG1) - S5-16 (GND4)	10 to 14 V
   S7-6 (IG1) - S5-22 (GND3)	10 to 14 V
   S7-6 (IG1) - S8-6 (GND2)	10 to 14 V
   S7-6 (IG1) - S8-31 (GND1)	10 to 14 V
   S7-6 (IG1) - Body ground	10 to 14 V

4. Measure the resistance of the wire harness side connectors.

   Standard resistance

   Tester Connection	Specified Condition
   S5-16 (GND4) - Body ground	Below 1 Ω
   S5-22 (GND3) - Body ground	Below 1 Ω
   S8-6 (GND2) - Body ground	Below 1 Ω
   S8-31 (GND1) - Body ground	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS AND CONNECTOR 

OK: Go to next step 

1. Check for open and short circuits in the multiplex communication system between the skid control ECU and combination meter. Refer to DIAGNOSTIC TROUBLE CODE CHART .

NG → REPAIR OR REPLACE HARNESS AND CONNECTOR 

OK: Go to next step 

1. Check the combination meter. Refer to PROBLEM SYMPTOMS TABLE .

NG → REPAIR OR REPLACE COMBINATION METER ASSEMBLY 

OK → REPLACE SKID CONTROL ECU