DTC P0847: Transmission Fluid Pressure Switch B (3rd Clutch) Circuit Low

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 ).
This code is caused by an electrical circuit problem and cannot be caused by a mechanical problem in the transmission.

Turn the ignition switch to ON (II).
Clear the DTC with the HDS.
Check the 3rd Pressure Switch signal with the HDS in the A/T Data List when not the transmission is in 3rd gear.
Is the 3rd Pressure Switch OFF?

YES -Go to step 4.

NO -Go to step 7.
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. Slow down, and stop the wheels.
Monitor the OBD status for P0847 in the DTCs MENU with the HDS.
Does the HDS indicate FAILED?

YES -Go to step 7.

NO -If the HDS indicates PASSED, intermittent failure, the system is OK at this time. Check the OP3SW wire for an intermittent short to body ground in the wire between transmission fluid pressure switch B (3rd clutch) and the PCM. If the HDS indicates NOT COMPLETED, go to step 5.
Turn the ignition switch to LOCK (0).
Disconnect the transmission fluid pressure switch B (3rd clutch) connector.
Turn the ignition switch to ON (II).
Check the 3rd Pressure Switch signal with the HDS in the A/T Data List.
Is the 3rd Pressure Switch OFF?

YES -Replace transmission fluid pressure switch B (3rd clutch) (see TRANSMISSION FLUID PRESSURE SWITCH B (3RD CLUTCH) REPLACEMENT ), then go to step 15.

NO -Go to step 11.
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 C38 and body ground.

Fig 1: Checking Continuity Between PCM Connector Terminal C38 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Repair a short to body ground in the wire between PCM connector terminal C38 and transmission fluid pressure switch B (3rd clutch), then go to step 15.

NO -Go to step 22.
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 3rd gear in D for at least 2 seconds, then press the accelerator pedal so that the transmission upshifts to 4th gear. Drive the vehicle in 4th gear for at least 2 seconds. Slow down, and stop the wheels.
Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0847 indicated?

YES -Check for an intermittent short to body ground in the wire between transmission fluid pressure switch B (3rd clutch) and the PCM, then go to step 1.

NO -Go to step 21.
Monitor the OBD status for P0847 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 20, go to the INDICATED DTC'S TROUBLESHOOTING .

NO -If the HDS indicates FAILED, check for an intermittent short to body ground in the wire between transmission fluid pressure switch B (3rd clutch) and the PCM, then go to step 1. If the HDS indicates NOT COMPLETED, go to step 18.
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 3rd gear in D for at least 2 seconds, then press the accelerator pedal so that the transmission upshifts to 4th gear. Drive the vehicle in 4th gear for at least 2 seconds. Slow down, and stop the wheels.
Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0847 indicated?

YES -Check for an intermittent short to body ground in the wire between transmission fluid pressure switch B (3rd clutch) and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then go to step 24. If the PCM was substituted, go to step 1.

NO -Go to step 27.
Monitor the OBD status for P0847 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 26, go to the INDICATED DTC'S TROUBLESHOOTING .

NO -If the HDS indicates FAILED, check for an intermittent short to body ground in the wire between the transmission fluid pressure switch B (3rd clutch) and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then go to step 24. If the PCM was substituted, go to step 1. If the HDS indicates NOT COMPLETED, go to step 24.