DTC P0641 (A/T)
DTC P0641: Sensor Reference Voltage 1 Circuit Malfunction
General Description
The transmission control module (TCM) is equipped with a sensor supply (5 V power source) to supply a stable 5 V to each sensor as reference voltage. The correct voltages for the sensors are loaded in the CPU of the TCM (A/D input) and when the sensor supply voltage (VCC) is a set value (high or low) for a certain time, the TCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 5 seconds or more |
| DTC Type | One drive cycle, MIL on, Shift position indicator blinks |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| 12 volt battery voltage [Battery Voltage] | 10 V | - |
[ ]: HDS Parameter
Malfunction Threshold
The sensor supply voltage (VCC) is more than 7.2 V, or less than 2 V, for at least 5 seconds.
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.
- Mainshaft speed sensor VCC line short to ground
- Transmission fluid pressure sensor B VCC line short to ground
- Transmission fluid pressure sensor D VCC line short to ground
- Two-way clutch actuator valve stroke sensor VCC line short to ground
- Mainshaft speed sensor VCC line short to power
- Transmission fluid pressure sensor B VCC line short to power
- Transmission fluid pressure sensor D VCC line short to power
- Two-way clutch actuator valve stroke sensor VCC line short to power
- Mainshaft speed sensor failure
- TCM internal circuit failure
Confirmation Procedure
Operating Condition
Turn the vehicle to the ON mode, and wait for at least 5 seconds.
With the HDS
None.
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected, the MIL comes on, the shift position indicator blinks, and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the TCM memory.
Conditions for clearing the DTC
The shift position indicator comes off by turning the vehicle to the OFF (LOCK) 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.