NO.6 BRAKE SYSTEM WARNING LIGHT STAYS ON 4 S OR MORE WHEN IGNITION SWITCH TURNED TO ON POSITION [ABS]

6	Brake system warning light stays on 4 s or more when ignition switch turned to ON position (Parking brake is released)
POSSIBLE CAUSE	• Brake fluid amount is low • Improper brake switch signal input to PCM (Vehicle without malfunction warning light, applied VIN (assumed): NC18215550—, NC18250831—, NC30202488—, NCA8251024—) • ABS HU/CM DTC is stored • Instrument cluster malfunction • Parking brake switch, brake fluid level sensor or in some other part malfunction • Short to ground in wiring harness between the following terminals: ― Instrument cluster terminal 2M and parking brake switch terminal A ― Instrument cluster terminal 1D and brake fluid level sensor terminal A • ABS HU/CM malfunction • 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)

Brake system warning light stays on 4 s or more when ignition switch turned to ON position

(Parking brake is released)

POSSIBLE CAUSE

• Brake fluid amount is low

• Improper brake switch signal input to PCM (Vehicle without malfunction warning light, applied VIN (assumed): NC18**215550—, NC18**250831—, NC30**202488—, NCA8**251024—)

• ABS HU/CM DTC is stored

• Instrument cluster malfunction

• Parking brake switch, brake fluid level sensor or in some other part malfunction

• Short to ground in wiring harness between the following terminals:

― Instrument cluster terminal 2M and parking brake switch terminal A

― Instrument cluster terminal 1D and brake fluid level sensor terminal A

• ABS HU/CM malfunction

• 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)

STEP	INSPECTION	ACTION
1	INSPECT BRAKE FLUID LEVEL • Inspect the brake fluid level. • Is the brake fluid level normal?	Yes	Vehicles without malfunction warning light (Applied VIN (assumed): NC18215550—, NC18250831—, NC30202488—, NCA8251024—) Go to the next step. Others Go to step 3.
No	Add the brake fluid.
2	CONFIRM PCM DTC • Perform the Reading DTCs Procedure. (See ON-BOARD DIAGNOSTIC TEST [L8, LF].) • Is the DTC P0571 and/or P0703 present?	Yes	Go to the applicable DTC inspection. (See DTC P0571 [L8, LF].) (See DTC P0703 [L8, LF].)
No	Go to the next step.
^*3	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 7.
No	Go to the next step.
4	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.
5	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.)
6	VERIFY WHETHER MALFUNCTION IS IN PARKING BRAKE SWITCH OR BRAKE FLUID LEVEL SENSOR, OR IN SOME OTHER PART • Disconnect the connectors in the following order: 1. Parking brake switch connector 2. Brake fluid level sensor connector • Does the brake system warning light go out with ignition switch turned to the ON position?	Yes	Replace the parking brake switch and/or brake fluid level sensor (short with some internal part). (See MASTER CYLINDER REMOVAL/INSTALLATION.) (See PARKING BRAKE LEVER REMOVAL/INSTALLATION.)
No	Inspect the wiring harness between the following terminals for short to ground: • Instrument cluster terminal 2M (brake system warning light) and parking brake switch terminal A • Instrument cluster terminal 1D (brake system warning light) and brake fluid level sensor terminal A If the wiring harness has a malfunction: • Repair or replace the wiring harness for a possible short to ground. If the wiring harness is normal: • Replace the ABS HU/CM. (See ABS HU/CM REMOVAL/INSTALLATION.)
^*7	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.
^*8	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.
^*9	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.)

STEP

INSPECTION

ACTION

INSPECT BRAKE FLUID LEVEL

• Inspect the brake fluid level.

• Is the brake fluid level normal?

Yes

Vehicles without malfunction warning light (Applied VIN (assumed): NC18**215550—, NC18**250831—, NC30**202488—, NCA8**251024—)

Go to the next step.

Others

Go to step 3.

Add the brake fluid.

CONFIRM PCM DTC

• Perform the Reading DTCs Procedure.

(See ON-BOARD DIAGNOSTIC TEST [L8, LF].)

• Is the DTC P0571 and/or P0703 present?

Yes

Go to the applicable DTC inspection.

(See DTC P0571 [L8, LF].)

(See DTC P0703 [L8, LF].)

Go to the next step.

^*3

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 7.

Go to the next step.

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].)

Go to the next step.

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.

Replace the instrument cluster.

(See INSTRUMENT CLUSTER REMOVAL/INSTALLATION.)

VERIFY WHETHER MALFUNCTION IS IN PARKING BRAKE SWITCH OR BRAKE FLUID LEVEL SENSOR, OR IN SOME OTHER PART

• Disconnect the connectors in the following order:

1. Parking brake switch connector

2. Brake fluid level sensor connector

• Does the brake system warning light go out with ignition switch turned to the ON position?

Yes

Replace the parking brake switch and/or brake fluid level sensor (short with some internal part).

(See MASTER CYLINDER REMOVAL/INSTALLATION.)

(See PARKING BRAKE LEVER REMOVAL/INSTALLATION.)

Inspect the wiring harness between the following terminals for short to ground:

• Instrument cluster terminal 2M (brake system warning light) and parking brake switch terminal A

• Instrument cluster terminal 1D (brake system warning light) and brake fluid level sensor terminal A

If the wiring harness has a malfunction:

• Repair or replace the wiring harness for a possible short to ground.

If the wiring harness is normal:

• Replace the ABS HU/CM.

(See ABS HU/CM REMOVAL/INSTALLATION.)

^*7

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.

Repair or replace the wiring harness for a possible open circuit.

^*8

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.

Go to the next step.

^*9

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.

Replace the ABS HU/CM (ABS HU/CM internal communication circuit malfunction).

(See ABS HU/CM REMOVAL/INSTALLATION.)

• When performing an asterisked (^*) troubleshooting inspection, slightly shake the wiring harness and connectors while performing the inspection to discover whether poor contact points are the cause of any intermittent malfunctions. If there is a problem, verify that the connectors, terminals and wiring harness are connected correctly and undamaged.