Automatic Transmission

DTC P0734: Problem in 4th Clutch and 4th Clutch Hydraulic Circuit (4th gear incorrect ratio)

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review General Troubleshooting Information.

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 13.

NO - Replace the ATF, then go to step 4.

4. Measure the line pressure.

Is the line pressure within service limit?

YES - Go to step 5.

NO - Repair the ATF pump and the regulator valve, or replace the transmission, then go to step 13.

5. Measure the 4th clutch pressure.

Is the 4th clutch pressure within the service limit?

YES - Go to step 6.

NO - Shift valves A, B, C, and D are stuck. Repair the shift valves and the hydraulic circuit, or replace the transmission, then go to step 11.

6. Clear the DTC with the HDS.
7. 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.

8. Turn the ignition switch to LOCK (0). Repeat the test-drive in step 7, then go to step 9.
9. Check for DTCs with the HDS.

Is DTC P0734 indicated?

YES - Repair the 4th clutch, or replace the transmission, then go to step 13.

NO - Go to step 10.

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

Does the screen indicate PASSED?

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

NO - If the screen indicated FAILED, repair the 4th clutch, or replace the transmission. If the screen indicates NOT COMPLETED, go to step 7.

11. Turn the ignition switch to ON (II).
12. Clear the DTC with the HDS.
13. Test-drive under these conditions:

^ Din 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.

14. Turn the ignition switch to LOCK (0). Repeat the test-drive in step 13, then go to step 15.
15. Check for 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 16.

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

Does the screen indicate PASSED?

YES - Troubleshooting is complete. If any other DTCs were indicated in step 15, go to the indicated DTC's troubleshooting.

NO - If the screen 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 screen indicates NOT COMPLETED, go to step 13.