DTC Troubleshooting

DTC Troubleshooting: P0734 (64)

DTC P0734:

Problem in 4th Clutch and 4th Clutch Hydraulic Circuit (4th Gear Incorrect Gear Ratio)

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot with the HDS, and review General Troubleshooting Information Reading and Clearing Diagnostic Trouble Codes.

1. Warm up the engine to normal operating temperature (the radiator fan comes on).

2. Make sure that the transmission is filled to the proper level, and check for fluid leaks.

3. Drain the ATF through a strainer. Inspect the strainer for metal debris or excessive clutch material.

Does the strainer have metal debris or excessive clutch material?

YES -

Replace the transmission, then go to step 11.

NO -

Replace the ATF, then go to step 4.

4. Measure the line pressure A/T Pressure Test.

Is the line pressure within the service limit?

YES -

Go to step 5.

NO -

Repair the ATF pump and the regulator valve, or replace the transmission, then go to step 11.

5. Measure the 4th clutch pressure A/T Pressure Test.

Is the 4th clutch pressure within the service limit?

YES -

Go to step 6.

NO -

Shift valve B, shift valve C, the servo control valve, and the servo valve are stuck. Inspect and repair the stuck valve, and the related hydraulic circuit, or replace the transmission, then go to step 11.

6. Turn the ignition switch to ON (II).

7. Clear the DTC with the HDS.

8. Test-drive under these conditions:

- D in 4th gear.
- Engine speed 1,000 rpm or more.
- Drive the vehicle at speeds over 7 mph (12 km/h) for at least 12 seconds.

9. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0734 indicated?

YES -

Repair the 4th clutch, or replace the transmission, then go to step 11.

NO -

Go to step 10.

10. Monitor the OBD STATUS for P0734 in the DTCs MENU with the HDS.

Does the HDS indicate PASSED?

YES -

Intermittent failure, the system is OK at this time. If any other Pending or Confirmed DTCs were indicated in step 9, go to the indicated DTC's troubleshooting.�

NO -

If the HDS indicated FAILED, repair the 4th clutch, or replace the transmission, then go to step 11. If the HDS indicates NOT COMPLETED, go to step 8.

11. Test-drive under these conditions:

- D in 4th gear.
- Engine speed 1,000 rpm or more.
- Drive the vehicle at speeds over 7 mph (12 km/h) for at least 12 seconds.

12. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0734 indicated?

YES -

Check for poor connections or loose terminals at the input shaft (mainshaft) speed sensor and the output shaft (countershaft) speed sensor and the PCM, then go to step 4.

NO -

Go to step 13.

13. Monitor the OBD STATUS for P0734 in the DTCs MENU with the HDS.

Does the HDS indicate PASSED?

YES -

Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step 12, go to the indicated DTC's troubleshooting.�

NO -

If the HDS indicates FAILED, check for poor connections or loose terminals at the input shaft (mainshaft) speed sensor and the output shaft (countershaft) speed sensor and the PCM, then go to step 4. If the HDS indicates NOT COMPLETED, go to step 11.