Expand AllThe transmission control computer ASSY performs shifting from gear 1 to gear 6 according to the combination of solenoids SL1, SL2, SL3, S1, S2, and S3. In case of a short-circuit or a wire break of one of the solenoid valve systems, the transmission control computer ASSY switches the other solenoids ON or OFF as a failsafe function. In case of failure of all solenoid valves, the circuit becomes just a mechanical hydraulic circuit and manual shifting is performed. (In case of a wire break or a short-circuit, the transmission control computer ASSY stops energizing the failed solenoid.)
| DTC No. |
|
Inspection part |
| P0748/25 |
|
|
| P0778/26 |
|
|
| DTC No. |
|
Inspection part |
| P0748/25 |
|
|
| P0778/26 |
|
|
Detail
- Disconnect connectors A and B of the transmission wire.
- Check the resistance between the terminals.
Standard:
Terminal No. (terminal symbol) Resistance value [Ω] B5 (SL1+) ↔ B10 (SL-) 5.0-6.0 (20°C, 68°F) A6 (SL2+) ↔ A12 (SL2-) 5.0-6.0 (20°C, 68°F) - Use the SST (electrical tester) and check the insulation of the terminals.
Standard:
Terminal No. (terminal symbol) Resistance value [Ω] B5 (SL1+) ↔ Body earth 1 MΩ or more A6 (SL2+) ↔ Body earth 1 MΩ or more Inspection result
Status Step SL1 trouble To step A SL2 trouble To step B Normal To OK
(A): To step 3
(B): To step 4
Proceed to [2]INSPECT WIRE HARNESS AND CONNECTOR (TRANSMISSION WIRE - TRANSMISSION CONTROL COMPUTER ASSY)
- Connect connectors A and B of the transmission wire and disconnect connector A of the transmission control computer ASSY.
- Check the resistance between the terminals. (Refer to page for the terminal layout.)
Standard:
Terminal No. (terminal symbol) Resistance value [Ω] A9 (SL1+) ↔ A8 (SL1-) 5.0-6.0 (20°C, 68°F) A7 (SL2+) ↔ A6 (SL2-) 5.0-6.0 (20°C, 68°F)
Repair or replace wire harness and connector.
Inspect and replace the transmission control computer ASSY.
- Disconnect the connector of the transmission solenoid ASSY (SL1)
- Check the resistance between terminals 1 and 2.
Standard:
5.0-6.0Ω (20°C, 68°F)
Replace the automatic transmission ASSY.
Repair or replace the transmission wire.
- Disconnect the connector of the transmission solenoid ASSY (SL2)
- Check the resistance between terminals 1 and 2.
Standard:
5.0-6.0Ω (20°C, 68°F)
Replace the automatic transmission ASSY.
Repair or replace the transmission wire
- Confirm the DTC P0748/25 is inactive
- Start the engine and let it idling condition.
- Verify the DTC P0748/25 is inactive.
- DTC Clear
- Clear the DTC with Hino DX
- Confirm the same DTC is not reoccurred
- P0748/25 is reoccurF Return to first process
- Other DTC appearF Refer to concerned Trouble shooting
Complete
