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 12.

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

4. Measure the line pressure.

Is the line pressure within service limits?

YES - Go to step 5.

NO - Repair the ATF pump and the regulator valve, or replace the transmission, then go to step 12.

5. Measure the 4th clutch pressure.

Is the 4th clutch pressure within service limits?

YES - Go to step 6.

NO - Shift valve B, shift valve C, the servo control valve, and the servo valve are stuck. Repair these valves and the hydraulic circuit, or replace the transmission, then go to step 12.

6. Turn the ignition switch to ON (II).
7. Clear the DTC with the HDS.
8. Test-drive the vehicle under these conditions:

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

9. Turn the ignition switch to LOCK (0), and repeat the test-drive in step 8.
10. Check for DTCs with the HDS.

Is DTC P0734 indicated?

YES - Repair the 4th clutch, or replace the transmission, then go to step 12.

NO - Go to step 11.

11. 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 10, go to the indicated DTC's troubleshooting.

NO - lithe screen indicates FAILED, repair the 4th clutch, or replace the transmission. If the screen indicates NOT COMPLETED, go to step 8.

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

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

15. Turn the ignition switch to LOCK (0), and repeat the test-drive in step 14.
16. 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 17.

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

Does the screen indicate PASSED?

YES - If the PCM was updated, troubleshooting is complete. If any other DTCs were indicated in step 16, go to the indicated DTC's troubleshooting.

NO - If the screen indicates FAILED, check for poor connections or loose terminals between the input shaft (mainshaft) speed sensor and the output shaft (countershaft) speed sensor and the PCM. If the screen indicates NOT COMPLETED, go to step 14.