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DTC P0843: Transmission Fluid Pressure Switch A (2nd Clutch) (Open or Stuck OFF)

WARNING: This page is about a different car, the 2013 Honda Fit, 2012 Honda Fit, 2011 Honda Fit, 2010 Honda Fit, and 2009 Honda Fit. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
  • Before you troubleshoot, record all freeze data and any on-board snapshot with the HDS, and review General Troubleshooting Information (see GENERAL TROUBLESHOOTING INFORMATION ).
  • This code is caused by an electrical circuit problem and cannot be caused by a mechanical problem in the transmission.
  • Some wire colors vary according to the model year, and are indicated with an asterisk as follows:
    • *(1): '09 - 10 models
    • *(2): '11 - 12 models
  1. Clear the DTC with the HDS.
  2. Start the engine, and warm it up to normal operating temperature (the radiator fan comes on).
  3. Shift into 2nd gear, and verify Shift Control display in the HDS:
    • Seven-position transmission: Shift to 2 while pressing the brake pedal, and verify with the HDS in the A/T data list that the Shift Control indicates 2nd.
    • Five-position transmission: Shift to S while pressing the brake pedal, upshift to 2nd gear by pulling the paddle shifter + (upshift switch), and verify with the HDS in the A/T data list that the Shift Control indicates 2nd.
  4. Check the 2nd Pressure Switch signal with the HDS in the A/T data list.

    Is the 2nd Pressure Switch ON? 

    YES  -Go to step 5.

    NO  - go to step  7.

  5. Test-drive the vehicle:
    • Seven-position transmission: Drive the vehicle in 2 for at least 2 seconds, then slow down to a stop.
    • Five-position transmission: Drive the vehicle in 2nd gear in the sequential sportshift mode in S for at least 2 seconds, then slow down to a stop.
  6. Monitor the OBD status for P0843 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.

    Does the HDS indicate FAILED? 

    YES  -Go to step 7.

    NO  -Intermittent failure, the system is OK at this time. Check for poor connections and loose terminals at the transmission fluid pressure switch A (2nd clutch) and the PCM. If the HDS indicates NOT COMPLETED, return to step  5 and recheck.

  7. Measure the 2nd clutch pressure (see PRESSURE TEST ).

    Is the 2nd clutch pressure within the service limits? 

    YES  -Go to step 8.

    NO  -Repair shift valves A, B, and C, and related hydraulic circuit, or replace the transmission, then go to step  22.

  8. Turn the ignition switch to LOCK (0).
  9. Disconnect the transmission fluid pressure switch A (2nd clutch) connector.
  10. Turn the ignition switch to ON (II).
  11. Measure the voltage between the transmission fluid pressure switch A (2nd clutch) connector terminal and body ground.
    Fig 1: Measuring Voltage Between Transmission Fluid Pressure Switch A (2Nd Clutch) Connector Terminal And Body Ground
    G06768356Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there about 5 V? 

    YES  -Replace the transmission fluid pressure switch A (2nd clutch) (see OUTPUT SHAFT (COUNTERSHAFT) SPEED SENSOR REPLACEMENT ), then go to step  22.

    NO  -Go to step 12.

  12. Turn the ignition switch to LOCK (0).
  13. Jump the SCS line with the HDS.
  14. Disconnect PCM connector B (49P).
  15. Check for continuity between PCM connector terminal B8 and the transmission fluid pressure switch A (2nd clutch) connector terminal.
    Fig 2: Checking Continuity Between PCM Connector Terminal B8 And Transmission Fluid Pressure Switch A (2Nd Clutch) Connector Terminal
    G06768357Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 16.

    NO  -Repair an open in the wire between PCM connector terminal B8 and the transmission fluid pressure switch A (2nd clutch), then go to step  22.

  16. Reconnect all connectors.
  17. Update the A/T software in the PCM if it does not have the latest software (see ECM/PCM UPDATE ), or substitute a known-good PCM (see SUBSTITUTING THE ECM/PCM ).
  18. Start the engine, and warm it up to normal operating temperature (the radiator fan comes on).
  19. Test-drive the vehicle:
    • Seven-position transmission: Drive the vehicle in 2nd gear in D for at least 2 seconds, then press the accelerator pedal so that the transmission upshifts into 4th gear, and drive in 4th gear for at least 2 seconds. Slow down and stop the engine.
    • Five-position transmission: Drive the vehicle in 2nd gear in the sequential sportshift mode in S for at least 2 seconds, then upshift to 4th gear by pulling the paddle shifter + (upshift switch), and drive in 4th gear for at least 2 seconds. Slow down and stop the engine.
  20. Check for Pending or Confirmed DTCs with the HDS.

    Is DTC P0843 indicated? 

    YES  -If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE ECM/PCM ), then recheck. If the PCM was substituted, go to step  1.

    NO  -Go to step 21.

  21. Monitor the OBD status for P0843 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.

    Does the HDS indicate PASSED? 

    YES  -If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM (see ECM/PCM REPLACEMENT ). If any other DTCs were indicated on step 20, go to the indicated DTC's troubleshooting.

    NO  -Check for poor connections and loose terminals at the transmission fluid pressure switch A (2nd clutch) and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE ECM/PCM ), then recheck. If the PCM was substituted, go to step  1. If the HDS indicates NOT COMPLETED, return to step  19 and recheck.

  22. Reconnect all connectors.
  23. Clear the DTC with the HDS.
  24. Start the engine, and warm it up to normal operating temperature (the radiator fan comes on).
  25. Test-drive the vehicle:
    • Seven-position transmission: Drive the vehicle in 2nd gear in D for at least 2 seconds, then press the accelerator pedal so that the transmission upshifts into 4th gear, and drive in 4th gear for at least 2 seconds. Slow down and stop the engine.
    • Five-position transmission: Drive the vehicle in 2nd gear in the sequential sportshift mode in S for at least 2 seconds, then upshift to 4th gear by pulling the paddle shifter + (upshift switch), and drive in 4th gear for at least 2 seconds. Slow down and stop the engine.
  26. Check for Pending or Confirmed DTCs with the HDS.

    Is DTC P0843 indicated? 

    YES  -Check for poor connections and loose terminals at the transmission fluid pressure switch A (2nd clutch) and the PCM, then go to step  1.

    NO  -Go to step 27.

  27. Monitor the OBD status for P0843 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.

    Does the HDS indicate PASSED? 

    YES  -Troubleshooting is complete. If any other DTCs were indicated on step 26, go to the indicated DTC's troubleshooting.

    NO  -Check for poor connections and loose terminals at the transmission fluid pressure switch A (2nd clutch) and the PCM, then go to step  1. If the HDS indicates NOT COMPLETED, return to step  25 and recheck.

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