DTC Troubleshooting

DTC Troubleshooting: P0756 (71-3)

DTC P0756:

Shift Solenoid Valve B Stuck OFF

NOTE:

- Before you troubleshoot, record all freeze data and any on-board snapshot with the HDS, and review General Troubleshooting Information How to Troubleshoot the A/T System.
- If DTC P0756 is stored in the PCM, the transmission does not shift to any gear other than 2nd or 5th gear because of the fail-safe function.

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 ATF Replacement 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.�

NO -

Replace the ATF ATF Replacement, then go to step 4.

4. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

5. Clear the DTC with the HDS.

6. Start the engine.

7. With the brake pedal pressed, shift to D, and check the A/T Shift Sol VLV. B signal, the Input Shaft (Mainshaft) Speed, and the Shift Control with the HDS in the A/T Data List.

Is the Input Shaft (Mainshaft) Speed 0 rpm when A/T Shift Sol VLV. B is OFF, and about the same as the engine speed when A/T Shift Sol VLV. B is ON?

YES -

Shift to P, and go to step 10.

NO -

Shift to P, and go to step 8.

8. Clear the DTC with the HDS.

9. With the brake pedal pressed, shift to D, and check the A/T Shift Sol VLV. B signal, the Input Shaft (Mainshaft) Speed, and the Shift Control with the HDS in the A/T Data List.

Does the Input Shaft (Mainshaft) Speed remain steady when A/T Shift Sol VLV. B is OFF and when it is ON?

YES -

Faulty 1st gear one-way clutch. Replace the countershaft 1st gear or the transmission. If you are replacing the countershaft 1st gear, clean off any metal debris or excessive clutch material inside the transmission, the ATF cooler, the ATF hoses, the ATF pipes, and the hydraulic circuit. Then, replace the countershaft 1st gear and the torque converter.�

NO -

Intermittent failure, the system is OK at this time.�

10. Select Shift Solenoid Valve B in the Miscellaneous Test Menu, and check that shift solenoid valve B operates with the HDS.

Is a clicking sound heard?

YES -

Go to step 11.

NO -

Faulty shift solenoid valve B. Replace the secondary valve body (shift solenoid valve B) Secondary Valve Body Replacement.�

11. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

12. Raise the vehicle on a lift, make sure it is securely supported, and allow all four wheels to rotate freely.

13. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

14. Clear the DTC with the HDS.

15. Start the engine, disable the VSA by pressing the VSA OFF button. With the brake pedal pressed, shift to S, and upshift to 2nd gear by pressing the paddle shifter + (upshift switch).

16. Run the vehicle, and upshift to 3rd gear by pressing the paddle shifter + (upshift switch), and check the 3rd Pressure Switch signal, the 6th Pressure Switch signal, and the Shift Control with the HDS in the A/T Data List. Slow down, and stop the wheels.

In 3rd gear, was the 3rd Pressure Switch OFF and was the 6th Pressure Switch ON?

YES -

Faulty shift valve B. Replace the secondary valve body (shift valve B) Secondary Valve Body Replacement.�

NO -

Faulty shift valve C. Replace the main valve body (shift valve C) or the transmission. If you are replacing the main valve body, clean off any metal debris or excessive clutch material inside the transmission, the ATF cooler, the ATF hoses, the ATF pipes, and the hydraulic circuit. Then, replace the main valve body and the torque converter.�