Visual Inspection and Diagnostic Pre-checks
WARNING: This page is about a different car, the 2020 Ford Explorer. 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.
Harness Side
Harness Side
- AC1: CHECK FOR ABS MODULE DTCS
- Ignition ON, engine OFF.
Carry out the ABS self-test.
- 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 ABS Module DTC Chart. Go to AC2.
- Ignition ON, engine OFF.
- AC2: CHECK THE PCM FOR DTCS
Carry out the PCM KOEO self-test.
- Are any 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.
If the scan tool cannot communication with the PCM, DIAGNOSE the no communication concern. REFER to the Module Communications Network article.Go to AC3.
- Are any DTCs present in the PCM?
- AC3: CHECK THE BPP 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 the Exterior Lighting article.
- For brake pedal installation, refer to the Hydraulic Brake Actuation article.
- 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 the Hydraulic Brake Actuation article or Exterior Lighting article
- 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 BPP (BOO1) PID
- Ignition ON, engine OFF.
- Access the PCM and monitor the BOO1 (MODE) PID.
- Apply and release the brake pedal.
- Does the PID reflect the brake pedal movement?
Yes No Go to AC5. DIAGNOSE the stoplamps. REFER to the Exterior Lighting article.
- AC5: CHECK THE ABS MODULE BRAKE PRESSURE PID
- Access the ABS and monitor the BRKHYDPRESS (PRESS) PID.
- Access the ABS and monitor the BPS_EE12 (PRESS) PID.
- Apply and release 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 (BOO_ABS) PID
- Access the ABS and monitor the BOO_ABS (MODE) PID.
- Access the ABS and monitor the BRAKE_SW (MODE) PID.
- Access the ABS and monitor the BRK_SWPED (MODE) PID.
- Apply and release the brake pedal.
- Does the PID reflect the brake pedal movement?
- AC7: CHECK FOR CORRECT ABS MODULE TO HCU FASTENER TORQUE VALUES
- AC8: CHECK FOR RETURNING ABS MODULE DTCS
- Ignition ON, engine OFF.
- Clear the ABS DTCs.
- Put the ABS module in sleep mode by performing the following steps:
- With ALL doors closed, set the ignition from ON to OFF.
- Disconnect the diagnostic scan tool.
- Open the door, exit the vehicle and close the door.
- Wait a minimum of 90 seconds for the ABS module to enter sleep mode.
- Ignition ON, engine OFF.
- Test drive the vehicle, carry out at least 3 stops.
Carry out the ABS self-test.
- Are any of the DTCs in the DTC Fault Trigger Conditions table preset and active in the ABS module?
Yes No Go to AC9. The condition causing the concern has been repaired. RETURN the vehicle to the customer.
- AC9: VERIFY ALL WIRING CONNECTIONS
- Ignition OFF.
- ABS_A Module connector disconnected. (C135A)
- ABS_B Module connector disconnected. (C135B)
- AC10: CHECK FOR APPLICABLE SERVICE ARTICLES
- Check OASIS for any service articles: TSB, GSB, SSM or FSA.
- Do any applicable service articles exist?
- AC11: CHECK FOR CORRECT ABS MODULE OPERATION
- BPP Switch connector connected. (C278) Make sure the connector seats and latches correctly.
- Operate the system and determine if the concern is still present.
- Is the concern still present?
Yes No CHECK OASIS for any applicable service articles: TSB, GSB, SSMs 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 brake pedal switch (also known as a stoplamp switch). REFER to the Exterior Lighting article.The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues.
- AC12: CHECK FOR CORRECT ABS OPERATION
- BPP Switch connector connected. (C278) Make sure the connector seats and latches correctly.