NO.4 BOTH ABS WARNING LIGHT AND BRAKE SYSTEM WARNING LIGHT STAY ON 4 S OR MORE WHEN THE IGNITION SWITCH IS TURNED TO THE ON POSITION [ABS]

id0403a5802000

4

Both ABS warning light and brake system warning light stay on 4 s or more when the ignition switch is turned to the ON position

POSSIBLE CAUSE

•  ABS HU/CM power supply fuse malfunction ―  Short to ground in ABS HU/CM power supply circuit ―  ABS HU/CM power supply fuse malfunction •  ABS HU/CM DTC is stored •  Instrument cluster malfunction •  ABS HU/CM malfunction (open or short circuit in ABS HU/CM internal ground circuit) •  Battery malfunction •  Charging system malfunction •  ABS HU/CM looseness •  Open circuit in wiring harness between ABS HU/CM terminal D and body ground •  Open circuit in wiring harness between ABS HU/CM terminal Y, Z and DLC-2 •  Short to power supply in wiring harness between ABS HU/CM terminal D and body ground •  Short to ground in wiring harness between ABS HU/CM terminal D and body ground •  ABS HU/CM malfunction (ABS HU/CM internal communication circuit malfunction)

Diagnostic procedure

STEP	INSPECTION		ACTION
1	INSPECT ABS HU/CM POWER SUPPLY FUSE •  Turn the ignition switch off. •  Inspect the ABS HU/CM power supply fuse. •  Is there any malfunction?	Yes	Inspect the blown fuse related wiring harness for short to ground. Repair or replace the wiring harness for a possible short to ground, if necessary. Install the appropriate amperage fuse.
		No	Go to the next step.
2	INSPECT WIRING HARNESS BETWEEN ABS HU/CM AND DLC‐2 FOR CONTINUITY AND SHORTS •  Perform the Reading DTCs Procedure. (See ON-BOARD DIAGNOSIS [ABS].) •  Is the error message displayed regarding communication between ABS HU/CM and M-MDS?	Yes	If a communication error message is displayed even after inspecting according to the procedure displayed on the M-MDS, go to Step 10.
		No	Go to the next step.
3	CONFIRM ABS HU/CM DTC •  Perform the Reading DTCs Procedure. (See ON-BOARD DIAGNOSIS [ABS].) •  Are any DTC present?	Yes	Go to the applicable DTC inspection. (See ON-BOARD DIAGNOSIS [ABS].)
		No	Go to the next step.
4	INSPECT WARNING LIGHT OPERATION •  Turn on the all warning light on instrument cluster using the instrument cluster input/output check code 26. (See INSTRUMENT CLUSTER INPUT/OUTPUT CHECK MODE.) •  Do the ABS and brake system warning light illuminate?	Yes	Go to the next step.
		No	Replace the instrument cluster. (See INSTRUMENT CLUSTER REMOVAL/INSTALLATION.)
5	INSPECT ABS HU/CM IGNITION POWER SUPPLY SYSTEM •  Perform the PID/Data Monitor and Record Procedure and access the ABS_VOLT PID. (See ON-BOARD DIAGNOSIS [ABS].) •  Is the voltage within the specification? Specification: approx. 10 V	Yes	Replace the ABS HU/CM (open or short circuit in ABS HU/CM internal ground circuit ). (See ABS HU/CM REMOVAL/INSTALLATION.)
		No	Go to the next step.
6	INSPECT BATTERY •  Inspect the battery. (See BATTERY INSPECTION [L8, LF].) •  Is there any malfunction?	Yes	Inspect the charging system. (See GENERATOR INSPECTION [L8, LF].) Repair or replace the malfunctioning part according to the inspection results.
		No	Go to the next step.
7	INSPECT CHARGING SYSTEM •  Start the engine. •  Measure the battery voltage with the electrical load (A/C, headlight, etc.) on and the engine idling. •  Is the voltage normal?	Yes	Go to the next step.
		No	Inspect the charging system (drive belt tension, generator, etc.). (See GENERATOR INSPECTION [L8, LF].) Repair or replace the malfunctioning part according to the inspection results.
*8	INSPECT ABS HU/CM POWER SUPPLY CIRCUIT FOR CONTINUITY •  Turn the ignition switch off. •  Disconnect the ABS HU/CM connector. •  Turn the ignition switch to the ON position (engine off). •  Measure the voltage at ABS HU/CM terminal Z (wiring harness-side). •  Is the voltage approx. 12 V?	Yes	Go to the next step.
		No	Inspect the ABS HU/CM connector for loose. Reconnect the ABS HU/CM connector properly, if necessary.
*9	INSPECT ABS HU/CM GROUND CIRCUIT FOR CONTINUITY •  Turn the ignition switch off. •  Inspect for continuity between ABS HU/CM terminal D (wiring harness-side) and body ground. •  Is there continuity?	Yes	If a malfunction error message is displayed on the M-MDS in Step 1 inspection: •  Go to the next step. If a malfunction error message is not displayed on the M-MDS in Step 1 inspection: •  Symptom troubleshooting is completed.
		No	Repair or replace the wiring harness for a possible open circuit.
*10	INSPECT WIRING HARNESS BETWEEN ABS HU/CM AND DLC‐2 FOR CONTINUITY •  Turn the ignition switch off. •  Inspect for continuity between ABS HU/CM terminal Y, Z and DLC-2 (wiring harness-side). •  Is there continuity?	Yes	Go to the next step.
		No	Repair or replace the wiring harness for a possible open circuit.
*11	INSPECT WIRING HARNESS BETWEEN ABS HU/CM AND DLC‐2 FOR SHORT TO POWER SUPPLY •  Turn the ignition switch to the ON position (engine off). •  Measure the voltage at ABS HU/CM terminal Y, Z (wiring harness-side). •  Is the voltage approx. 12 V?	Yes	Repair or replace the wiring harness for a possible short to power supply.
		No	Go to the next step.
*12	INSPECT WIRING HARNESS BETWEEN ABS HU/CM AND DLC‐2 FOR SHORT TO GROUND •  Turn the ignition switch off. •  Inspect for continuity between ABS HU/CM terminal Y, Z (wiring harness-side) and body ground. •  Is there continuity?	Yes	Repair or replace the wiring harness for a possible short to ground.
		No	Replace the ABS HU/CM (ABS HU/CM internal communication circuit malfunction). (See ABS HU/CM REMOVAL/INSTALLATION.)