Real Time AWD System Symptom Troubleshooting - Abnormal noise (AWD)

Abnormal noise 

NOTE:  If necessary, compare the noise with a known-good vehicle of the same type, if the noise is remarkably abnormal, do the following troubleshooting.

• 1. Problem verification (abnormal noise check) 1:

  - 1. Test-drive the vehicle and check for the abnormal noise.

  Did abnormal noise reappear?

  YES 

  The failure is duplicated. Go to step 2.

  NO 

  Check the following items.

  • Check the rear differential fluid level and the fluid condition - Refer to: Rear Differential Fluid Inspection and Replacement (4WD) Rear Differential Fluid Inspection and Replacement (AWD)  .
  • Check for rear differential fluid leaks.
  • Check for interference with items such as the harness.
  • Rotate either rear wheel by hand, and check that the other wheel rotates.
  • Do the OIL PRESSURE CONTROL TEST in the FUNCTIONAL TEST with the HDS - Refer to: Rear Differential Dual Pump System Function Test (4WD) Rear Differential Pressure Test (AWD)  .
  • Do the rear differential fluid pressure sensor test .
• 2. Rear differential visual check:

  - 1. Check the following items.

  • Check the rear differential fluid level and the fluid condition - Refer to: Rear Differential Fluid Inspection and Replacement (4WD) Rear Differential Fluid Inspection and Replacement (AWD)  .
  • Check for rear differential fluid leaks.
  • Check for interference with items such as the harness.

  Are the check results OK?

  YES 

  The rear differential visual is OK. Go to step 3.

  NO 

  Replace the rear differential fluid or add recommended fluid - Refer to: Rear Differential Fluid Inspection and Replacement (4WD) Rear Differential Fluid Inspection and Replacement (AWD)  .

• 3. Problem verification (rear differential companion flange rotate check):

  - 1. Release the parking brake.

  - 2. Shift the transmission to N position.

  - 3. Raise the vehicle on a lift .

  - 4. Disconnect the No. 2 propeller shaft from the rear differential companion flange.

  - 5. Rotate the companion flange by hand.

  Can the rear differential companion flange be rotated smoothly by hand?

  YES 

  Go to step 4.

  NO 

  The failure is duplicated. Replace the torque control differential (TCD) assembly or the differential carrier assembly - Refer to: Rear Differential Disassembly and Reassembly (4WD) Rear Differential Disassembly and Reassembly (AWD)  .

• 4. Rear differential operation check:

  - 1. Rotate either rear wheel by hand, and check that the other wheel rotates.

  Does the other wheel rotate?

  YES 

  The rear differential operation is OK. Go to step 5.

  NO 

  Replace the differential carrier assembly - Refer to: Rear Differential Disassembly and Reassembly (4WD) Rear Differential Disassembly and Reassembly (AWD)  .

• 5. Torque control differential (TCD) assembly check:

  - 1. Connect the No. 2 propeller shaft.

  - 2. Remove the following fuse.

  Fuse	No. B6 (7.5 A)
  Location	Under-dash fuse/relay box

  - 3. Test-drive the vehicle on the lift.

  Is the abnormal noise still present?

  YES 

  Replace the torque control differential (TCD) assembly - Refer to: Rear Differential Disassembly and Reassembly (4WD) Rear Differential Disassembly and Reassembly (AWD)  .

  NO 

  The torque control differential (TCD) assembly is OK. Go to step 6.

• 6. Rear differential solenoid valve check:

  - 1. Select the FUNCTIONAL TEST in the REAL TIME AWD with the HDS.

  - 2. Select the SOLENOID TEST in the FUNCTIONAL TEST with the HDS.

  - 3. Do LEVEL 7 of the SOLENOID TEST with the HDS.

  Solenoid Test

  - 4. Do LEVEL 1 of the SOLENOID TEST with the HDS.

  Solenoid Test

  Did the abnormal noise happen when changing from LEVEL 7 to LEVEL 1?

  YES 

  Replace the rear differential solenoid valve - Refer to: Rear Differential Disassembly and Reassembly (4WD) Rear Differential Disassembly and Reassembly (AWD)  .

  NO 

  The rear differential solenoid valve is OK. Go to step 7.

• 7. Rear differential pump motor check:

  - 1. Select the ADJUSTMENT in the REAL TIME AWD with the HDS.

  - 2. Do the AIR BLEEDING in the ADJUSTMENT with the HDS .

  Air Bleeding

  - 3. Listen for any abnormal noise coming from the rear differential pump motor.

  Did abnormal noise happen while doing air bleeding?

  YES 

  Replace the rear differential pump motor .

  NO 

  The rear differential pump motor is OK. Go to step 8.

• 8. Problem verification (abnormal noise check) 2:

  - 1. Replace the rear differential fluid - Refer to: Rear Differential Fluid Inspection and Replacement (4WD) Rear Differential Fluid Inspection and Replacement (AWD)  .

  - 2. Select the ADJUSTMENT in the REAL TIME AWD with the HDS.

  - 3. Do the AIR BLEEDING in the ADJUSTMENT with the HDS .

  Air Bleeding

  - 4. Test-drive the vehicle on the lift.

  Did abnormal noise reappear?

  YES 

  The failure is duplicated. Replace the torque control differential (TCD) assembly or the differential carrier assembly - Refer to: Rear Differential Disassembly and Reassembly (4WD) Rear Differential Disassembly and Reassembly (AWD)  .

  NO 

  Intermittent failure, the system is OK at this time.