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

General Description


Transmission fluid pressure switch B (3rd clutch) is installed in the hydraulic pressure circuit to the 3rd clutch. When hydraulic pressure is supplied to the 3rd clutch, the switch is turned on. When hydraulic pressure is not supplied to the 3rd clutch, the switch is turned off. The signal from transmission fluid pressure switch B (3rd clutch) is input to the powertrain control module (PCM). The PCM detects the hydraulic pressure supply conditions at the gear change to 3rd gear (2nd ? 3rd) to reduce the shock that occurs at the gear change. If transmission fluid pressure switch B (3rd clutch) is on while driving the vehicle with the rotation speed ratio of the input/output pulses is other than the 3rd gear ratio (the ratio is Neutral or 4th), the PCM detects a transmission fluid pressure switch B (3rd clutch) failure and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status
Execution
Continuous
Sequence
None
Duration
Depending on the driving conditions
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, P0848, P0872, P0873, 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 B (3rd clutch) [3rd Pressure Switch] to the PCM is low for at least 4 seconds when the shift lever is in P, R, or N.
The input signal from transmission fluid pressure switch B (3rd clutch) [3rd Pressure Switch] to the PCM is low for at least 4 seconds when driving in 6th gear.
The input signal from transmission fluid pressure switch B (3rd clutch) [3rd Pressure Switch] to the PCM is low for at least 4 seconds when the 6th gear shift is commanded or when the shift lever is in P, R, or N, after the signal is low for at least 2 seconds when driving in 1st, 2nd, 4th, or 5th gear.

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 B (3rd clutch) OP3SW line short to ground
Transmission fluid pressure switch B (3rd clutch) stuck on
PCM internal circuit failure

Confirmation Procedure
Operating Condition
1.
Start the engine.
2.
Drive the vehicle in D until the transmission shifts into 6th gear.
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.