Pinpoint Test X: The Brake Warning Indicator Is Always On

WARNING: This page is about a different car, the 2006 Mercury Milan, 2006 Lincoln Zephyr, and 2006 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: Use the correct probe adaptor(s) when making measurements. Failure to use the correct probe adaptor(s) may damage the connector.

X1 CHECK THE BASE BRAKE SYSTEM
- Operate the brakes and verify that the base braking system operates correctly.
- Does the base braking system operate correctly?
Yes : GO to X2.

No : REFER to BRAKE SYSTEM-GENERAL INFORMATION .
X2 CHECK THE ABS WARNING INDICATOR OPERATION
- Key in ON position.
- Monitor the ABS warning indicator and the brake warning indicator following prove-out.
- Do both the ABS and brake warning indicators remain on after prove-out?
Yes : DIAGNOSE the ABS warning indicator first. GO to PINPOINT TEST N .

No : GO to X3.
X3 CHECK FOR INSTRUMENT CLUSTER DTCs
- Key in OFF position.
- Check for recorded instrument cluster DTCs from the continuous and on-demand self-tests.
- Is DTC U1901 recorded?
Yes : REPAIR all SJB DTCs. If no SJB DTCs are present, REFER to MODULE COMMUNICATIONS NETWORK to diagnose no communication with the SJB.

No : GO to X4.
X4 RETRIEVE THE RECORDED DTCs FROM BOTH THE CONTINUOUS AND ON-DEMAND SJB SELF-TESTS
NOTE: Make sure that the parking brake is fully released and the brake fluid level is full.
- Check for recorded SJB DTCs from the continuous and on-demand self-tests.
- Are any SJB DTCs recorded?
Yes : If DTC B2479 is retrieved, GO to X6.

If DTC C1125 is retrieved, GO to X9.

For all other SJB DTCs, REFER to the SMART JUNCTION BOX (SJB) DIAGNOSTIC TROUBLE CODE (DTC) INDEX .

No : GO to X5.
X5 CARRY OUT THE INSTRUMENT CLUSTER INDICATOR LAMP CONTROL ACTIVE COMMAND USING THE SCAN TOOL
- Key in ON position.
- Enter the following diagnostic mode on the scan tool: Instrument Cluster Active Command.
- Select the instrument cluster indicator lamp control active command BRK_LAMP. Command the brake warning indicator on then off. Observe the brake warning indicator.
- Does the brake warning indicator illuminate when commanded on and turn off when commanded off?
Yes : GO to X11.

No : GO to X12.
X6 CHECK THE PARKING BRAKE WARNING INDICATOR SWITCH PID
- Key in ON position.
- Enter the following diagnostic mode on the scan tool: SJB PID.
- Monitor the SJB parking brake warning indicator switch PID PRK_BRAKE while applying and releasing the parking brake.
- Does the PID agree with the parking brake position?
Yes : GO to X11.

No : GO to X7.
X7 CHECK THE PARKING BRAKE WARNING INDICATOR SWITCH
- Disconnect: Parking Brake Warning Indicator Switch C306.
- Enter the following diagnostic mode on the scan tool: SJB PID.
- Monitor the SJB parking brake warning indicator switch PID PRK_BRAKE.
- Does the PID indicate that the parking brake is off?
Yes : INSTALL a new parking brake warning indicator switch. REFER to PARKING BRAKE & ACTUATION . CLEAR the DTCs. REPEAT the self-test.

No : GO to X8.
X8 CHECK CIRCUIT CCB09 (GY/BU) FOR A SHORT TO GROUND
- Key in OFF position.
- Disconnect: SJB C2280c.
- Measure the resistance between the SJB C2280c-9, circuit CCB09 (GY/BU), harness side and ground.
  
  Fig 1: Checking Circuit CCB09 (GY/BU) For Short To Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms?
Yes : GO to X11.

No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
X9 CHECK THE SJB OPERATION USING THE SCAN TOOL
- Key in OFF position.
- Disconnect: Brake Fluid Level Switch C124.
- Key in ON position.
- Enter the following diagnostic mode on the scan tool: SJB Self-Test.
- Clear the SJB DTCs. Repeat the SJB on-demand self-test.
- Is DTC C1125 still present?
Yes : GO to X10.

No : VERIFY that the brake fluid level is full. INSTALL a new brake fluid reservoir. REFER to HYDRAULIC BRAKE ACTUATION . CLEAR the DTCs. REPEAT the self-test.
X10 CHECK CIRCUIT CMC19 (GY/VT) FOR A SHORT TO GROUND
- Key in OFF position.
- Disconnect: SJB C2280a.
- Measure the resistance between the SJB C2280a-25, circuit CMC19 (GY/VT), harness side and ground.
  
  Fig 2: Checking Circuit CMC19 (GY/VT) For Short To Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms?
Yes : GO to X11.

No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
X11 CHECK FOR CORRECT SJB OPERATION
- Disconnect all the SJB connectors.
- Check for:
  - Corrosion
  - Damaged pins
  - Pushed-out pins
- Connect all the SJB connectors and make sure they seat correctly.
- Operate the system and verify that the concern is still present.
- Is the concern still present?
Yes : INSTALL a new SJB. REFER to MULTIFUNCTION ELECTRONIC CONTROL MODULES . TEST the system for normal operation.

No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
X12 CHECK FOR CORRECT INSTRUMENT CLUSTER OPERATION
- Disconnect the instrument cluster connector.
- Check for:
  - Corrosion
  - Damaged pins
  - Pushed-out pins
- Connect the instrument cluster connector and make sure it seats correctly.
- Operate the system and verify that the concern is still present.
- Is the concern still present?
Yes : INSTALL a new instrument cluster. REFER to INSTRUMENT CLUSTER . TEST the system for normal operation.

No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.