DTC P0756 (6-Speed A/T)

DTC P0756  : Shift Solenoid Valve B Stuck OFF

NOTE: 

• Before you troubleshoot, review the General Troubleshooting Information - Refer to: 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.

DTC (A/T)

1. ATF check

   - 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 - Refer to: Automatic Transmission Removal and Installation (6-Speed A/T) .

   NO 

   Replace the ATF - Refer to: ATF Replacement (6-Speed A/T) , then go to step 2.

2. Determine possible failure area (shift solenoid valve B, others)

   - 1. Turn the vehicle to the ON mode.

   - 2. Clear the DTC with the HDS.

   - 3. Start the engine.

   - 4. With the brake pedal pressed, shift to D, and check the parameter (s) below with the HDS.

   Signal	Current conditions
   	Values	Unit
   A/T Shift Sol VLV. B
   Input Shaft (Mainshaft) Speed (rpm)
   Shift Control

   Is the Input Shaft (Mainshaft) Speed (rpm) 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 4.

   NO 

   Shift to P, and go to step 3.

3. Problem verification

   - 1. Clear the DTC with the HDS.

   - 2. With the brake pedal pressed, shift to D, and check the parameter (s) below with the HDS.

   Signal	Current conditions
   	Values	Unit
   A/T Shift Sol VLV. B
   Input Shaft (Mainshaft) Speed (rpm)
   Shift Control

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

   YES 

   The failure is duplicated. Faulty 1st gear one-way clutch. Replace the countershaft 1st gear (1st gear one-way clutch) or the transmission - Refer to: Automatic Transmission Removal and Installation (6-Speed A/T) . If replacing the countershaft 1st gear, clean off any metal debris or excessive clutch material inside the transmission, 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. If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot.

4. Shift solenoid valve B check

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

   Shift Solenoid Valve B

   Is a clicking sound heard?

   YES 

   Shift solenoid valve B is OK. Go to step 5.

   NO 

   Faulty shift solenoid valve B. Replace the secondary valve body (shift solenoid valve B) .

5. Shift valve B check

   - 1. Turn the vehicle to the OFF (LOCK) mode.

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

   - 3. Turn the vehicle to the ON mode.

   - 4. Clear the DTC with the HDS.

   - 5. Start the engine.

   - 6. Disable the VSA by pressing the VSA OFF button.

   NOTE: Enter the VSA maintenance mode in case of the vehicle speed above 31 mph (50 km/h).

   - 7. Run the vehicle, and shift the transmission to 2nd gear, then to 3rd gear, and check the parameter (s) below with the HDS. Slow down, and stop the wheels.

   Signal	Current conditions
   	Values	Unit
   3rd Pressure Switch
   6th Pressure Switch
   Shift Control

   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) or the transmission - Refer to: Automatic Transmission Removal and Installation (6-Speed A/T) .

   NO 

   Shift valve B is OK. Faulty shift valve C. Replace the main valve body (shift valve C) or the transmission - Refer to: Automatic Transmission Removal and Installation (6-Speed A/T) . If replacing the main valve body, clean off any metal debris or excessive clutch material inside the transmission, the ATF hoses, the ATF pipes, and the hydraulic circuit. Then, replace the main valve body and the torque converter.