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

General Description


Transmission fluid pressure switch C (4th clutch) is installed in the hydraulic pressure circuit to the 4th clutch. When hydraulic pressure is supplied to the 4th clutch, the switch is turned on. When hydraulic pressure is not supplied to the 4th clutch, the switch is turned off. The signal from transmission fluid pressure switch C (4th clutch) is input to the powertrain control module (PCM). The PCM detects the hydraulic pressure supply conditions at the gear change to 4th gear (3rd ? 4th) to reduce the shock that occurs at the gear change. If transmission fluid pressure switch C (4th clutch) is off while driving the vehicle with the rotation speed ratio of the input/output pulses is that of the 4th gear ratio, the PCM detects a transmission fluid pressure switch C (4th clutch) failure and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status
Execution
Continuous
Sequence
None
Duration
4 seconds or more
DTC Type
Two drive cycles, MIL on, A/T gear position indicator blinks
OBD Status
PASSED/FAILED/NOT COMPLETED (STILL TESTING)

Enable Conditions
Condition
Minimum
Maximum
Battery voltage
[BATTERY VOLTAGE]
11 V
–
No active DTCs set (prevents monitor from running)
P0122, P0123, P0222, P0223, P0705, P0716, P0717, P0718, P0721, P0722, P0723, P0746, P0747, P0751, P0752, P0756, P0757, P0761, P0762, P0776, P0777, P0796, P0797, P0842, P0843, P0847, P0848, P0872, P0877, P0878, P0962, P0963, P0966, P0967, P0970, P0971, P0973, P0974, P0976, P0977, P0979, P0980, P0989, P0990, P1658, P1659, P1683, P1684, P2101, P2118, P2122, P2123, P2127, P2128, P2135, P2138, P2176, P2714, P2720, P2721
[ ]: HDS Parameter

Malfunction Threshold
One of these conditions occurs:
The input signal from transmission fluid pressure switch C (4th clutch) [4th Pressure Switch] to the PCM is high when driving in 4th gear.
The input signal from transmission fluid pressure switch C (4th clutch) [4th Pressure Switch] to the PCM is high when driving in R.

Possible Cause
NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
Transmission fluid pressure switch C (4th clutch) OP4SW line short to power
Transmission fluid pressure switch C (4th clutch) OP4SW line open (includes connector loose connection or disconnection)
Transmission fluid pressure switch C (4th clutch) stuck off
PCM internal circuit failure

Confirmation Procedure
Operating Condition
1.
Start the engine.
2.
Drive the vehicle in 4th gear for at least 4 seconds.
Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.
With the HDS
None.

Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on, the A/T gear position indicator blinks, and a Confirmed DTC and the freeze data are stored.

Conditions for clearing the DTC
The A/T gear position indicator comes off by pressing the engine start/stop button to select the OFF mode. The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command.