DTC P0873: Transmission Fluid Pressure Switch C (4th Clutch) Circuit High

WARNING: This page is about a different car, the 2013 Honda Odyssey, 2012 Honda Odyssey, and 2011 Honda Odyssey. 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 ).

Turn the ignition switch to ON (II).
Clear the DTC with the HDS.
Start the engine, and warm it up to normal operating temperature (the radiator fan comes on).
Test-drive the vehicle in 4th gear in D, and verify that the Shift Control indicates 4th.
Check the 4th Pressure Switch signal with the HDS in the A/T Data List.
Is the 4th Pressure Switch ON?

YES -Go to step 6.

NO -Go to step 8.
Test-drive the vehicle in 4th gear in D for at least 2 seconds. Slow down, and stop the wheels.
Monitor the OBD status for P0873 in the DTCs MENU with the HDS.
Does the HDS indicate FAILED?

YES -Go to step 8.

NO -If the HDS indicates PASSED, intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at transmission fluid pressure switch C (4th clutch) and the PCM. If the HDS indicates NOT COMPLETED, go to step 6.
Turn the ignition switch to LOCK (0).
Disconnect the transmission fluid pressure switch C (4th clutch) connector.
Connect a jumper wire between the transmission fluid pressure switch C (4th clutch) connector terminal and body ground.

Fig 1: Connecting Jumper Wire Between Transmission Fluid Pressure Switch C (4th Clutch) Connector Terminal And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Turn the ignition switch to ON (II).
Check the 4th Pressure Switch signal with the HDS in the A/T Data List.
Is the 4th Pressure Switch ON?

YES -Go to step 13.

NO -Go to step 16.
Reconnect the transmission fluid pressure switch C (4th clutch) connector.
Clear the DTC with the HDS.
Measure the 4th clutch pressure (see PRESSURE TEST ).
Is the 4th clutch pressure within the service limit?

YES -Replace transmission fluid pressure switch C (4th clutch) (see TRANSMISSION FLUID PRESSURE SWITCH C (4TH CLUTCH) REPLACEMENT ), then go to step 20.

NO -Replace the main valve body and the secondary valve body, or replace the transmission, then go to step 23.
Turn the ignition switch to LOCK (0).
Jump the SCS line with the HDS.
Disconnect PCM connector C (49P).
Check for continuity between PCM connector terminal C37 and the transmission fluid pressure switch C (4th clutch) connector terminal.

Fig 2: Checking Continuity Between PCM Connector Terminal C37 And Transmission Fluid Pressure Switch C (4th Clutch) Connector Terminal
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 27.

NO -Repair an open in the wire between PCM connector terminal C37 and transmission fluid pressure switch C (4th clutch), then go to step 20.
Reconnect all connectors.
Turn the ignition switch to ON (II).
Clear the DTC with the HDS.
Start the engine, and warm it up to normal operating temperature (the radiator fan comes on).
Test-drive the vehicle in 4th gear in D for at least 2 seconds, then press the accelerator pedal so that the transmission upshifts to 5th gear. Drive the vehicle in 5th gear for at least 2 seconds. Slow down, and stop the wheels.
Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0873 indicated?

YES -Check for poor connections or loose terminals between transmission fluid pressure switch C (4th clutch) and the PCM, then go to step 1.

NO -Go to step 26.
Monitor the OBD status for P0873 in the DTCs MENU with the HDS.
Does the HDS indicate PASSED?

YES -Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step 25, go to the INDICATED DTC'S TROUBLESHOOTING .

NO -If the HDS indicates FAILED, check for poor connections or loose terminals between transmission fluid pressure switch C (4th clutch) and the PCM, then go to step 1. If the HDS indicates NOT COMPLETED, go to step 23.
Reconnect all connectors.
Update the PCM if it does not have the latest software (see PCM UPDATE ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ).
Start the engine, and warm it up to normal operating temperature (the radiator fan comes on).
Test-drive the vehicle in 4th gear in D for at least 2 seconds, then press the accelerator pedal so that the transmission upshifts to 5th gear. Drive the vehicle in 5th gear for at least 2 seconds. Slow down, and stop the wheels.
Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0873 indicated?

YES -Check for poor connections or loose terminals between transmission fluid pressure switch C (4th clutch) and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then go to step 29. If the PCM was substituted, go to step 1.

NO -Go to step 32.
Monitor the OBD status for P0873 in the DTCs MENU with the HDS.
Does the HDS indicate PASSED?

YES -If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM (see PCM REPLACEMENT ). If any other Pending or Confirmed DTCs were indicated in step 31, go to the INDICATED DTC'S TROUBLESHOOTING .

NO -If the HDS indicates FAILED, check for poor connections or loose terminals between transmission fluid pressure switch C (4th clutch) and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then go to step 29. If the PCM was substituted, go to step 1. If the HDS indicates NOT COMPLETED, go to step 29.