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DTC 138: Brake Pedal Position Switch Malfunction

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION  ).
  1. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
  2. Check for DTCs with the HDS.

    Is DTC 86 indicated with DTC 138 at the same time? 

    YES  -Do the DTC 86 troubleshooting (see DTC 86: F-CAN COMMUNICATION MALFUNCTION  ).

    NO  -Go to step 3.

  3. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.
  4. Check the No. 10(15 A) fuse in the under-hood fuse/relay box.

    Is the fuse blown? 

    YES  -Go to step 5.

    NO  -Reinstall the checked fuse, then go to step  15.

  5. Short the SCS line with the HDS.
  6. Disconnect the PCM connector A (49P) (see PCM REPLACEMENT ).
  7. Disconnect the brake pedal position switch 4P connector (see BRAKE PEDAL AND BRAKE PEDAL POSITION SWITCH ADJUSTMENT ).
  8. Check for continuity between PCM connector A (49P) terminal No. 8 and body ground.
    Fig 1: Checking Continuity Between PCM Connector A (49P) Terminal No. 8 And Body Ground
    G08076127Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair a short to body ground in the wire between the PCM and the brake pedal position switch.

    NO  -Go to step 9.

  9. Check for continuity between brake pedal position switch 4P connector terminal No. 1 and body ground.
    Fig 2: Checking Continuity Between Brake Pedal Position Switch 4P Connector Terminal No. 1 And Body Ground
    G08076128Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair a short to body ground in the wire between the No. 10 (15 A) fuse in the under-hood fuse/relay box and the brake pedal position switch.

    NO  -Go to step 10.

  10. Reconnect all connectors, then install a new No. 10 (15 A) fuse.
  11. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
  12. Clear the DTC with the HDS.
  13. Start the engine, then press the brake pedal slowly and hard.
  14. Check for DTCs with the HDS.

    Is DTC 138 indicated? 

    YES  -Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode, then go to step  21.

    NO  -The system is OK at this time.

  15. Disconnect the brake pedal position switch 4P connector (see BRAKE PEDAL AND BRAKE PEDAL POSITION SWITCH ADJUSTMENT ).
  16. Measure the voltage between brake pedal position switch 4P connector terminal No. 1 and body ground.
    Fig 3: Measuring Voltage Between Brake Pedal Position Switch 4P Connector Terminal No. 1 And Body Ground
    G08076129Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Go to step 17.

    NO  -Repair an open in the wire between the No. 10 (15 A) fuse in the under-hood fuse/relay box and the brake pedal position switch.

  17. Short the SCS line with the HDS.
  18. Disconnect the PCM connector A (49P) (see PCM REPLACEMENT ).
  19. Check for continuity between brake pedal position switch 4P connector terminal No. 2 and PCM connector A (49P) terminal No. 8.
    Fig 4: Checking Continuity Between Brake Pedal Position Switch 4P Connector Terminal No. 2 And PCM Connector A (49P) Terminal No. 8
    G08076130Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 20.

    NO  -Repair an open in the wire between the PCM and the brake pedal position switch.

  20. Reconnect all connectors.
  21. Do the brake pedal position switch test (see BRAKE PEDAL POSITION SWITCH TEST ).

    Is the brake pedal position switch OK? 

    YES  -Go to step 22.

    NO  -Replace the brake pedal position switch (see BRAKE PEDAL AND BRAKE PEDAL POSITION SWITCH ADJUSTMENT ).

  22. Update the PCM if it does not have the latest software (see PCM UPDATE ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ).
  23. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
  24. Clear the DTC with the HDS.
  25. Start the engine, then press the brake pedal slowly and hard.
  26. Check for DTCs with the HDS.

    Is DTC 138 indicated? 

    YES  -Check for loose terminals in the PCM connector A (49P). If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then retest. If the PCM was substituted, go to step 27.

    NO  -If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM (see PCM REPLACEMENT ).

  27. Update the VSA modulator-control unit if it does not have the latest software (see VSA MODULATOR-CONTROL UNIT UPDATE  ).
  28. Start the engine, then press the brake pedal slowly and hard.
  29. Check for DTCs with the HDS.

    Is DTC 138 indicated? 

    YES  -Check for loose terminals in the VSA modulator-control unit 46P connector. If the VSA modulator-control unit was updated and the symptom/indication is still present, replace the VSA modulator-control unit (see VSA MODULATOR-CONTROL UNIT REMOVAL AND INSTALLATION  ).

    NO  -If the VSA modulator-control unit was updated, troubleshooting is complete. If any other DTCs are indicated, go to the indicated DTCS TROUBLESHOOTING .

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