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

NOTE:

Before you troubleshoot, record all freeze data and any on-board snapshot with the HDS, and review the General Troubleshooting Information (see GENERAL TROUBLESHOOTING INFORMATION )
If DTC P0843 is stored in the PCM, the transmission does not shift to any gear other than 2nd through 4th gear because of the fail-safe function.

Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
Clear the DTC with the HDS.
With SH-AWD: Raise the vehicle on a lift, make sure it is securely supported, and allow all four wheels to rotate freely.
Without SH-AWD: Block the rear wheels, and raise the front of the vehicle, make sure it is securely supported, and allow the front wheels to rotate freely, or raise the vehicle on a lift.
Start the engine, disable the VSA by pressing the VSA OFF button. Run the vehicle with the sequential sportshift mode in 2nd gear. Check the 2nd Pressure Switch signal with the HDS in the A/T Data List. Slow down, and stop the wheels.
Is the 2nd Pressure Switch ON in 2nd gear?

YES - Intermittent failure, the system is OK at this time. Check for poor connections and loose terminals between transmission fluid pressure switch A (2nd clutch) and the PCM.

NO - Go to step 5.
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.
Disconnect the transmission fluid pressure switch A (2nd clutch) connector.
Connect a jumper wire between the transmission fluid pressure switch A (2nd clutch) connector terminal and body ground.

Fig 1: Identifying Jumper Wire Between Transmission Fluid Pressure Switch A (2nd Clutch) Connector Terminal And Body Ground Connection
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
Check the 2nd Pressure Switch signal with the HDS in the A/T Data List.
Is the 2nd Pressure Switch ON?

YES - Replace transmission fluid pressure switch A (2nd clutch) (see TRANSMISSION FLUID PRESSURE SWITCH A (2ND CLUTCH) REPLACEMENT ).

NO - Go to step 10.
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.
Remove the jumper wire.
Jump the SCS line with the HDS.
Disconnect PCM connector C (49P).
Check for continuity between PCM connector terminal C27 and the transmission fluid pressure switch A (2nd clutch) connector terminal.

Fig 2: Checking Continuity Between PCM Connector Terminal C27 And Transmission Fluid Pressure Switch A (2nd Clutch) Connector Terminal
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Replace the PCM (see ECM/PCM REPLACEMENT ).

NO - Repair an open in the wire between PCM connector terminal C27 and transmission fluid pressure switch A (2nd clutch).