Visual Inspection and Diagnostic Pre-checks
WARNING: This page is about a different car, the 2020 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
- Make sure the stoplamp switch electrical connector is connected and free of corrosion and other contaminants.
- Make sure the stoplamp switch is installed correctly.
- Make sure the stoplamp switch operates correctly.
- AC1: CHECK FOR ABS (ANTI-LOCK BRAKE SYSTEM) MODULE DTCS
- Ignition ON.
- Using a diagnostic scan tool, carry out the ABS ECU Reset routine.
- Are any lost communication with PCM, invalid data from PCM, pressure sensor, wheel speed sensor or stability control sensor DTCs present in the ABS module?
Yes No DIAGNOSE all lost communication with PCM, invalid data from PCM, pressure sensor, wheel speed sensor or stability control sensor DTCs before diagnosing DTC C0040:xx or C0044:xx. REFER to the appropriate ABS Module DTC Chart. Go to AC2.
- AC2: CHECK THE PCM (POWERTRAIN CONTROL MODULE) FOR DTCS (DIAGNOSTIC TROUBLE CODE)
Using a diagnostic scan tool, carry out the PCM KOEO self-test.
- Are there any Diagnostic Trouble Codes DTCs present in the PCM?
Yes No DIAGNOSE all PCM DTCs before diagnosing DTC C0040:xx or C0044:xx. REFER to the appropriate Electronic Engine Controls article. Go to AC3.
- Are there any Diagnostic Trouble Codes DTCs present in the PCM?
- AC3: CHECK THE BPP (BRAKE PEDAL POSITION) SWITCH AND BRAKE PEDAL ASSEMBLY INSTALLATION
- Inspect the BPP switch and brake pedal assembly. Verify there is no brake pedal pressure unintentionally applied due to incorrect BPP switch or brake pedal installation.
- For BPP (stoplamp) switch installation, refer to STOPLAMP SWITCH .
- For brake pedal installation, refer to HYDRAULIC CONTROL UNIT (HCU) .
- Is the stoplamp switch and brake pedal assembly installed correctly?
Yes No Go to AC4. REINSTALL the brake pedal assembly or BPP switch correctly.
refer to: STOPLAMP SWITCH .
refer to: HYDRAULIC CONTROL UNIT (HCU) .
- Inspect the BPP switch and brake pedal assembly. Verify there is no brake pedal pressure unintentionally applied due to incorrect BPP switch or brake pedal installation.
- AC4: CHECK THE PCM (POWERTRAIN CONTROL MODULE) BOO1 PID (PARAMETERIDENTIFICATION)
- AC5: CHECK THE ABS (ANTI-LOCK BRAKE SYSTEM) MODULE BRAKE PRESSURE PID (PARAMETER IDENTIFICATION)
- Using a diagnostic scan tool, monitor the ABS BRKHYDPRESS (Pressure) PID while pressing and releasing the brake pedal.
- Does the PID read approximately 0 PSI with the brake pedal released and then increase when the brake pedal is applied?
Yes No Go to AC6. GO to PINPOINT TEST Y .
- AC6: CHECK THE ABS MODULE BRAKE ON/OFF PID (PARAMETER IDENTIFICATION)
- Using a diagnostic scan tool, monitor the ABS brake pedal switch BOO_ABS (Status) PID while pressing and releasing the brake pedal
Does the PID reflect the brake pedal movement?
Yes No The system is operating correctly at this time. The DTC may have been set due tohigh network traffic or an intermittent fault condition. For Vacuum Brake Booster:
GO to AC7. - AC7: CHECK FOR CORRECT ABS (ANTI-LOCK BRAKE SYSTEM) MODULE TO HCU(HYDRAULIC CONTROL UNIT) TORQUE VALUES
- Ignition OFF.
- Verify all ABS module-to- HCU fasteners are tightened to their correct torque specifications.
- Refer to ANTI-LOCK BRAKE SYSTEM (ABS) MODULE
- Refer to HYDRAULIC CONTROL UNIT (HCU) .
- Are the ABS module-to- HCU fasteners tightened correctly?
Yes No Go to AC8. TIGHTEN all ABS module-to- HCU fasteners to their specified torque value.
Refer to ANTI-LOCK BRAKE SYSTEM (ABS) MODULE
Refer to HYDRAULIC CONTROL UNIT (HCU)
- AC8: VERIFY ALL WIRING CONNECTIONS
- Ignition OFF.
- Disconnect ABS Module Connector C135
- Disconnect BPP Switch Connector C278
- Using a good light source, inspect all disconnected electrical connectors for the following:
- Corrosion - install new connector or terminal and clean the module pins
- Damaged or bent pins - install new terminals or pins
- Pushed-out pins - install new pins as necessary
- Spread terminals - install new terminals as necessary
Are the connectors free of corrosion, damaged pins, bent pins, pushed-out pins and spread terminals?
Yes No Go to AC9. Refer to CONNECTOR REPAIR PROCEDURES . - AC9: CHECK FOR CORRECT ABS (ANTI-LOCK BRAKE SYSTEM) MODULE OPERATION
- Connect ABS Module connector C135 . Make sure the connector seats and latches correctly.
- Connect BPP Switch connector C278 . Make sure the connector seats and latches correctly.
- Operate the system and determine if the concern is still present.
Is the concern is still present?
Yes No CHECK OASIS for any service articles: TSB , GSB , SSM or FSA.
If a service article exists for this concern, DISCONTINUE this test and FOLLOW
the service article instructions. If no service articles address this concern, INSTALL a new BPP switch. Refer to STOPLAMP SWITCH .The system is operating correctly at this time. The concern may have been caused bya loose or corroded connector. ADDRESS the root cause of any connector or pin issues.