Pinpoint Test I: DTC C1285 - BOOSTER SOLENOID CIRCUIT FAILURE
WARNING: This page is about a different car, the 2005 Lincoln LS. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multimeter probes.
- I1 CARRY OUT THE BRAKE BOOSTER RECALIBRATION PROCEDURE
- Key in ON position.
- Enter the following diagnostic mode on the diagnostic tool: Clear DTC.
- Carry out the brake booster recalibration procedure using the diagnostic tool.
- Enter the following diagnostic mode on the diagnostic tool: Retrieve DTCs.
- Are any diagnostic trouble codes (DTCs) retrieved or does the recalibration procedure indicate a fault?
- Yes
: If DTC C1285 is retrieved, or the brake booster portion of the recalibration procedure indicates a failure, GO to 12.
If any other DTC is retrieved, GO to the ANTI-LOCK BRAKE SYSTEM (ABS) (WITH OR WITHOUT ADVANCE TRAC®/IVD) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX .
- No : The ABS system is operating correctly.
- I2 CHECK THE BRAKE BOOSTER SOLENOID
- Key in OFF position.
- Disconnect: Brake Booster C149.
- Measure the resistance between brake booster solenoid C149-3, component side and brake booster solenoid C149-4, component side.
- Is the resistance between 1 and 2 ohms?
- Yes : GO to 13.
- No : INSTALL a new brake booster. REFER to POWER BRAKE ACTUATION . CLEAR the DTC. RECALIBRATE the ABS module. FOLLOW the diagnostic tool directions for the calibration procedure. REFER to MODULE CONFIGURATION . REPEAT the self-test.
- I3 CHECK CIRCUIT 8-CF68 (WH/RD) AND CIRCUIT 9-CF68 (BN/RD) FOR AN OPEN
- Key in OFF position.
- Measure the resistance between ABS module C155-17, circuit 8-CF68 (WH/RD), harness side and brake booster C149-4, circuit 8-CF68 (WH/RD), harness side; and between ABS module C155-31, circuit 9-CF68 (BN/RD), harness side and brake booster C149-3, circuit 9-CF68 (BN/RD), harness side.
- Is the resistance less than 5 ohms?
- Yes : GO to 14.
- No : REPAIR the circuit in question. CLEAR the DTC. RECALIBRATE the ABS module. FOLLOW the diagnostic tool directions for the calibration procedure. REFER to MODULE CONFIGURATION . REPEAT the self-test.
- I4 CHECK CIRCUIT 8-CF68 (WH/RD) FOR A SHORT TO GROUND
- Measure the resistance between brake booster C149-4, circuit 8-CF68 (WH/RD), harness side and ground.
- Is the resistance greater than 10,000 ohms?
- Yes : GO to 15.
- No : REPAIR the circuit in question. CLEAR the DTC. RECALIBRATE the ABS module. FOLLOW the diagnostic tool directions for the calibration procedure. REFER to MODULE CONFIGURATION . REPEAT the self-test.
- I5 CHECK CIRCUIT 9-CF68 (BN/RD) FOR A SHORT TO VOLTAGE
- Disconnect: ABS Module C155.
- Key in ON position.
- Measure the voltage between brake booster solenoid C149-3, circuit 9-CF68 (BN/RD), harness side and ground.
- Is voltage present?
- Yes : REPAIR the circuit in question. CLEAR the DTC. RECALIBRATE the ABS module. FOLLOW the diagnostic tool directions for the calibration procedure. REFER to MODULE CONFIGURATION . REPEAT the self-test.
- No : GO to 16.
- I6 CHECK THE BRAKE BOOSTER SOLENOID FOR CORRECT OPERATION
- Connect: Brake Booster C149.
- Key in START position.
- Wait a few minutes to create engine vacuum in the brake booster and then place the ignition switch in the OFF position.
- Connect a fused (10A) jumper wire between ABS module C155-31, circuit 9-CF68 (BN/RD), harness side and ground; and connect a fused (10A) jumper wire for several seconds between ABS module C155-17, circuit 8-CF68 (WH/RD), harness side and the positive battery post, while observing the brake pedal for movement.
- Does the brake pedal move?
- Yes : INSTALL a new ABS module. REFER to ANTI-LOCK BRAKE SYSTEM (ABS) MODULE in this article . REPEAT the self-test.
- No : INSTALL a new brake booster. REFER to POWER BRAKE ACTUATION . CLEAR the DTC. RECALIBRATE the ABS module. REPEAT the self-test.