Expand AllThis is provided as signal input from the turbine speed sensor (NT) to the engine control computer. The turbine speed sensor (NT) signal and the vehicle speed sensor (SP2) signal are used to control engine torque and shift timing. Also, lock-up control is performed based on the engine speed signal.
| DTC No. |
|
Inspection part |
| P0715/12 |
|
|
Detail
- Set the ignition switch to ON.
- Check the voltage between the terminals off the transmission control computer.
Standard:
Terminal No.
(terminal symbol)Measuring condition Voltage [V] B1 (SP2+) ↔ B8 (GND1) Engine at idle speed 7-9
To step 3
Proceed to [2]INSPECT TRANSMISSION CONTROL COMPUTER ASSY BY ITSELF (INSPECT WAVEFORM)
- Connect an oscilloscope between terminals C1 (NT-) and B8 (GND1) of the transmission control computer ASSY.
- Inspect the waveform between the terminals of the transmission control computer ASSY.
Standard:
Item Contents Measuring terminal NT- ↔ GND1 Instrument setting 500mv/DIV, 500μs/DIV Measuring condition Engine at idle speed
The waveform cycle becomes shorter with increasing vehicle speed.
Inspect and replace the transmission control computer ASSY.
Proceed to [3]INSPECT WIRE HARNESS AND CONNECTOR (SPEED SENSOR (NT) - TRANSMISSION CONTROL COMPUTER ASSY)
- Inspect conductivity
- Disconnect the connector of the speed sensor (NT) and connectors B and C of the transmission control computer ASSY.
- Check the conductivity between the connector on the wire harness side of the transmission control computer ASSY and the connector on the wire harness side of the speed sensor (NT). (Refer to page for the terminal layout.)
Standard:
Terminal No. (terminal symbol)
(Transmission computer ↔ speed sensor)Conductivity B1 (SP2+) ↔ 1 (NIN+) Yes C1 (NT-) ↔ 2 (NIN-) Yes - Inspect insulation
- Check the insulation between the connector on the wire harness side of the transmission control computer ASSY and body earth. (Refer to page for the terminal layout.)
Standard:
Terminal No. (terminal symbol)
(Transmission computer)Conductivity B1 (SP2+) ↔ Body earth No C1 (NT-) ↔ Body earth No
Repair or replace wire harness and connector.
Replace speed sensor (NT).
- Confirm the DTC P0715/12 is inactive
- Start the engine and let it idling condition.
- Verify the DTC P0715/12 is inactive.
- DTC Clear
- Clear the DTC with Hino DX
- Confirm the same DTC is not reoccurred
- P0715/12 is reoccurF Return to first process
- Other DTC appearF Refer to concerned Trouble shooting
Complete
