NO.3 BRAKE SYSTEM WARNING LIGHT STAY ON [DYNAMIC STABILITY CONTROL (DSC)]


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3

Brake system warning lights stay on

POSSIBLE CAUSE
•  Brake fluid amount is low.
•  Electric Parking brake does not release.
•  Electric Parking brake switch signal error input to instrument cluster.
•  Brake fluid level sensor stuck on.
•  Short to ground in following circuit:
―  Between electric parking brake switch and instrument cluster
―  Between brake fluid level sensor and front body control module (FBCM)
•  No connection at DSC HU/CM connector (When DSC HU/CM connector comes off, ABS warning light, brake system warning light, TCS/DSC indicator light, and TCS OFF indicator light illuminate.)
•  DSC HU/CM detected malfunction. (Input and output device malfunction)
•  DSC HU/CM detects low voltage in power supply.
•  DSC HU/CM ground malfunction (When DSC HU/CM ground is not securely connected, ABS warning light, brake system warning light, TCS/DSC indicator light, and TCS OFF indicator light illuminate but diagnostic trouble code does not display.)
•  DSC HU/CM does not operate.
•  Front body control module (FBCM) detected malfunction.
•  DSC HU/CM internal malfunction
•  Instrument cluster detected malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION

1
INSPECT BRAKE FLUID AMOUNT AND VERIFY THAT ELECTRIC PARKING BRAKE RELEASED
•  Inspect the brake fluid amount and verify that the electric parking brake released.
•  Is the brake fluid amount normal?
•  Is the electric parking brake released?
Yes
Go to the next step.
No
Add the brake fluid or release the electric parking brake.
If the brake fluid refilled:
•  Inspect and repair the brake line for leakage.
2
CONFIRM DSC HU/CM DTC
•  Retrieve the DSC HU/CM DTC using the M-MDS.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
No
If communication error message is displayed on the M-MDS screen:
•  Go to the next step.
If communication error message is not displayed:
•  Go to Step 4.
3
INSPECT CONNECTION OF DSC HU/CM CONNECTOR
•  Inspect for connection of the DSC HU/CM connector.
•  Is the DSC HU/CM connector connected securely?
Yes
Go to the next step.
No
Connect the DSC HU/CM connector securely, then go to the next step.
4
CONFIRM INSTRUMENT CLUSTER OPERATION RECORD
•  Retrieve the warning system operation history using the M-MDS.
•  Is the brake system warning light illumination history recorded?
Yes
If the Brake Waning Lamp recorded:
•  Go to Step 5.
If the Brake Waning Lamp (Brake fluid low) recorded:
•  Go to Step 6.
If the Brake Waning Lamp (Electric parking brake ON over 20 km/h or 12.4 mile/h) recorded:
•  Go to Step 8.
No
Go to Step 10.
5
VERIFY WHETHER MALFUNCTION IS IN INSTRUMENT CLUSTER OR ELSEWHERE
•  Connect the M-MDS to the DLC-2.
•  Turn off and on all warning light and indicator lights using the instrument cluster PID WL+IL of active command modes.
•  Do the ABS warning light, brake system warning light, TCS/DSC indicator light and DSC OFF indicator light turn on and off according to the active command modes?
Yes
Go to Step 10.
No
Replace the instrument cluster.
6
INSPECT WHETHER MALFUNCTION IS IN BRAKE FLUID LEVEL SENSOR OR ELSEWHERE
•  Inspect the brake fluid level sensor for continuity.
•  Is the continuity condition normal?
Yes
Go to the next step.
No
Replace the malfunctioning part.
*7
INSPECT FOR SHORT TO GROUND IN WIRING HARNESS BETWEEN FRONT BODY CONTROL MODULE (FBCM) AND BRAKE FLUID LEVEL SENSOR
•  Inspect for short to ground in the following circuit:
―  Between brake fluid level sensor and front body control module (FBCM) terminal 2Q
•  Is the short to ground detected?
Yes
Repair or replace the wiring harness for a possible short to ground.
No
Retrieve the front body control module (FBCM) DTC using the M-MDS.
If the DTC remains:
•  Go to the applicable DTC inspection.
If the DTC does not remain:
•  Replace the front body control module (FBCM).
8
INSPECT WHETHER MALFUNCTION IS IN ELECTRIC PARKING BRAKE SWITCH OR ELSEWHERE
•  Inspect the following parts for continuity:
―  Electric Parking brake switch
•  Is the continuity condition normal?
Yes
Go to the next step.
No
Replace the malfunctioning part.
*9
INSPECT FOR SHORT TO GROUND IN WIRING HARNESS BETWEEN INSTRUMENT CLUSTER AND ELECTRIC PARKING BRAKE SWITCH
•  Inspect for short to ground in the following circuit:
―  Between electric parking brake switch terminal J and instrument cluster terminal L
•  Is the short to ground detected?
Yes
Repair or replace the wiring harness for a possible short to ground.
No
Retrieve the instrument cluster DTC using the M-MDS.
If the DTC remains:
•  Go to the applicable DTC inspection.
If the DTC does not remain:
•  Replace the instrument cluster.
10
INSPECT DSC HU/CM POWER SUPPLY FUSE
•  Inspect the DSC HU/CM ignition power supply fuse.
•  Is the fuse normal?
Yes
Go to the next step.
No
Inspect the blown fuse’s circuit for short to ground.
Repair or replace the wiring harness for a possible short to ground as necessary.
Install appropriate amperage fuse.
*11
VERIFY WHETHER MALFUNCTION IS IN WIRING HARNESS (BETWEEN DSC HU/CM POWER SUPPLY AND DSC HU/CM FOR CONTINUITY) OR ELSEWHERE
•  Switch the ignition ON.
•  Measure the voltage at the DSC HU/CM terminal AH (wiring harness-side).
•  Is the voltage approx. 12 V?
Yes
Go to the next step.
No
Refer to the wiring diagram and verify whether or not there is a common connector between DSC HU/CM terminal AH (wiring harness-side) and IG1 relay No.1 terminal C.
If there is a common connector:
•  Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
•  Repair or replace the malfunctioning part.
If there is no common connector:
•  Repair or replace the wiring harness which has an open circuit.
*12
VERIFY WHETHER MALFUNCTION IS IN WIRING HARNESS (BETWEEN DSC HU/CM AND GROUND FOR CONTINUITY) OR ELSEWHERE
•  Switch the ignition off.
•  Disconnect the DSC HU/CM connector.
•  Inspect for continuity between DSC HU/CM terminal B (wiring harness-side) and body ground.
•  Is there continuity?
Yes
Replace the DSC HU/CM. (open circuit in the DSC HU/CM)
No
Repair or replace the wiring harness for a possible open circuit and poor contact in ground point.

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