DTC P0721
DTC P0721: VNC/NOUT Performance
General Description
The dual speed sensor is integrated to the sensor unit in the transmission. The transmission control module (TCM) monitors the detected speed and direction of dual speed sensor (output speed), and the transmission output speed calculated from wheel speed sensor and dual speed sensor (input speed). If the one of following conditions continues for a specified duration, the TCM detects a malfunction and stores a DTC:
- The relation between detected speeds of dual speed sensor (output speed) and transmission output speed calculated from the wheel speed sensor is abnormal.
- The relation between detected speeds of dual speed sensor (output speed) and transmission output speed calculated from the dual speed sensor (input speed) is abnormal.
- The relation between vehicle running condition and speed direction detected at dual speed sensor (output speed) is abnormal.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 1 second or more |
| DTC Type | One drive cycle, MIL on, A/T gear position indicator blinks |
Enable Conditions
| Condition | ||
|---|---|---|
| Vehicle | During drive | |
Malfunction Threshold
One of these conditions is met:
- The difference between detected speeds of dual speed sensor (output speed) and transmission output speed calculated from wheel speed sensor is more than 250 rpm for at least 1 second.
- The difference between detected speeds of dual speed sensor (output speed) and transmission output speed calculated from dual speed sensor (input speed) is more than 250 rpm for at least 1 second.
- The direction of the vehicle running and speed direction detected at dual speed sensor (output speed) does not match for at least 1 second.
Possible Cause
The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
- Dual speed sensor NOUT line open (includes a loose or disconnected connector)
- Dual speed sensor VCC2 line open (includes a loose or disconnected connector)
- Dual speed sensor NOUT line short to ground
- Dual speed sensor VCC2 line short to ground
- Sensor unit failure (dual speed sensor)
- TCM internal failure
Confirmation Procedure
Operating Condition
- 1.
Start the engine.
- 2.
Drive the vehicle for a while.
- 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, the A/T gear position indicator blinks, the MIL comes on, and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the TCM memory.
Conditions for clearing the DTC
The A/T gear 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.