DTC Troubleshooting: P0873
DTC P0873: Transmission Fluid Pressure Switch C (4th Clutch) Circuit High
NOTE:
Before you troubleshoot, review the General Troubleshooting Information.
If DTC P0873 is stored in the PCM, the transmission does not shift to any gear other than 1st or 4th gear because of the fail-safe function.

DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P0873 Transmission Fluid Pressure Switch C (4th Clutch) Circuit High
      

1.
Problem verification:

Problem verification
?1.
Turn the vehicle to the ON mode.

?2.
Clear the DTC with the HDS.


?3.
Raise the vehicle on a lift. Make sure it is securely supported, and allow all four wheels to rotate freely.

?4.
Start the engine.

?5.
Disable the VSA by pressing the VSA OFF button.

NOTE: Enter the VSA maintenance mode in case of the vehicle speed above 31 mph (50 km/h).

?6.
Test-drive the vehicle in 4th gear, and check the parameter(s) below with the HDS. Slow down, and stop the wheels.
Signal
Threshold
Current conditions
Values
Unit
Values
Unit
4th Pressure Switch
ON
      

Do the current condition(s) match the threshold in 4th gear?

     
YES
     
     
     
Intermittent failure, the system is OK at this time. Check for poor connections and loose terminals between transmission fluid pressure switch C (4th clutch) and the PCM. If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot.?
     
NO
     
     
     
The failure is duplicated. Go to step 2.
2.
Determine possible failure area (transmission fluid pressure switch C (4th clutch), others):

Determine possible failure area (transmission fluid pressure switch C (4th clutch), others)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Disconnect the following connector.

?3.
Connect terminals A and B with a jumper wire.
Terminal A
Transmission fluid pressure switch C (4th clutch) 1P connector No. 1 (BLU)
Terminal B
Body ground


?4.
Turn the vehicle to the ON mode.

?5.
Check the parameter(s) below with the HDS.
Signal
Threshold
Current conditions
Values
Unit
Values
Unit
4th Pressure Switch
ON
      

Do the current condition(s) match the threshold?

     
YES
     
     
     
     
NO
     
     
     
Go to step 3.
3.
Open wire check (OP4SW line):

Open wire check (OP4SW line)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Remove the jumper wire.

?3.
Jump the SCS line with the HDS.


?4.
Disconnect the following connector.

?5.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Transmission fluid pressure switch C (4th clutch) 1P connector: disconnected
 
PCM connector B (51P): disconnected
Test circuit
OP4SW
Test point 1
Transmission fluid pressure switch C (4th clutch) 1P connector No. 1 (BLU)
Test point 2
PCM connector B (51P) No. 26 (BLU)


Is there continuity?

     
YES
     
     
     
The OP4SW wire is OK. Replace the PCM.?
     
NO
     
     
     
Repair an open in the OP4SW wire between transmission fluid pressure switch C (4th clutch) and the PCM.?