Pinpoint Test D: DTC B1484 - Brake Pedal Input Open Circuit

WARNING: This page is about a different car, the 2005 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: The Flex Probe Kit must be used for all test connections. Use of standard multimeter probes may damage wiring terminals.

D1 CHECK FOR CORRECT STOPLAMPS OPERATION
- Press the brake pedal.
- Do the stoplamps illuminate?
- Yes : GO to D2.
- No : REFER to EXTERIOR LIGHTING to continue diagnosis of the stoplamps.
D2 CHECK THE ANTI-LOCK BRAKE SYSTEM (ABS) MODULE BOO_ABS PID
- Enter the following diagnostic mode on the diagnostic tool: ABS Module PIDs.
- Key in ON position.
- Monitor the ABS module PID BOO_ABS, while pressing and releasing the brake pedal.
- Does the ABS module PID BOO_ABS indicate ON with the brake pedal pressed and OFF with the brake pedal released?
- Yes : CLEAR the DTCs. REPEAT the self-test. If DTC B1484 is retrieved again, INSTALL a new ABS module. REFER to ANTI-LOCK BRAKE SYSTEM (ABS) MODULE . REPEAT the self-test.
- No : GO to D3.
D3 CHECK CIRCUIT 1651 (WH/RD) FOR AN OPEN
NOTE: Make sure the brake pedal is released for this step.
- Key in OFF position.
- Disconnect: ABS module C135.
- Key in ON position.
- Press and hold the brake pedal.
- Measure the voltage between the ABS module C135 pin 6, circuit 1651 (WH/RD), harness side and the ABS module C135 pin 12, circuit 57 (BK), harness side.
  
  Fig 1: Measuring Voltage Between ABS Module C135 Pin 6, Circuit 1651 (WH/RD), Harness Side And ABS Module C135 Pin 12, Circuit 57 (BK), Harness Side
  Courtesy of FORD MOTOR CO.
- Are the voltages greater than 10 volts?
- Yes : GO to D4.
- No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
D4 CHECK FOR CORRECT ABS MODULE OPERATION
- Disconnect the ABS connector.
- Check for:
  - corrosion
  - pushed-out pins
- Connect the ABS connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
- Yes : INSTALL a new ABS module. REFER to ANTI-LOCK BRAKE SYSTEM (ABS) MODULE . CLEAR the DTCs. REPEAT the self-test.
- No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. CARRY OUT the self-test with the brake pedal not applied.