DTC P0840: Transmission Fluid Pressure Sensor/Switch A Circuit Out of Range (DCT) (2018-19)
General Description
The odd clutch pressure sensor uses a strain gauge. The output voltage changes depending on the secondary clutch pressure. The powertrain control module (PCM) sends a 5 V reference voltage to the sensor through a pull-up resistor. When the secondary clutch pressure is low, the sensor resistance decreases and the PCM detects a low signal voltage. Conversely, when the secondary clutch pressure is high, the sensor resistance increases and the PCM detects a high signal voltage. If the odd clutch pressure sensor signal voltage is out of the specified range, the PCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type, OBD Status
| Execution | Continuous |
| Sequence | None |
| Duration | 2 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 | |
|---|---|
| No active DTCs set (prevents monitor from running) | P0842, P0843 |
Malfunction Threshold
One of these conditions occurs:
- The odd clutch pressure sensor output voltage [Oil pressure sensor 1 voltage.] is less than 0.28 V for at least 2 second.
- The odd clutch pressure sensor output voltage [Oil pressure sensor 1 voltage.] is more than 4.56 V for at least 2 second.
[ ]: HDS Parameter
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.
- Odd clutch pressure sensor failure
Confirmation Procedure
Operating Condition
Start the engine in P position/mode, and wait for at least 2 seconds.
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 and a Confirmed DTC and the freeze data are stored.
Conditions for clearing the DTC
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 or by disconnecting the 12 volt battery.